Abstract. Paper presented at the 5th Laughter Workshop, Paris, 27-28 September 2018: While laughter intensity is an important characteristic immediately perceivable for the listeners, empirical investigations of this construct are still scarce. Here, we explore the relationship between human judgments of laughter intensity and laughter acoustics. Our results show that intensity is predicted by multiple dimensions, including duration, loudness, pitch variables, and center of gravity. Controlling for loudness confirmed the robustness of these effects and revealed significant relationships between intensity and other features, such as harmonicity and voicing. Together, the findings demonstrate that laughter intensity does not overlap with loudness. They also highlight the necessity of further research on this complex dimension.
Tuesday, April 28, 2020
Not Only Decibels: Exploring Human Judgments of Laughter Intensity
Rychlowska, Magdalena, Gary J. McKeown, Ian Sneddon, and Will Curran. 2020. “Not Only Decibels: Exploring Human Judgments of Laughter Intensity.” PsyArXiv. April 28. psyarxiv.com/x7qea
Abstract. Paper presented at the 5th Laughter Workshop, Paris, 27-28 September 2018: While laughter intensity is an important characteristic immediately perceivable for the listeners, empirical investigations of this construct are still scarce. Here, we explore the relationship between human judgments of laughter intensity and laughter acoustics. Our results show that intensity is predicted by multiple dimensions, including duration, loudness, pitch variables, and center of gravity. Controlling for loudness confirmed the robustness of these effects and revealed significant relationships between intensity and other features, such as harmonicity and voicing. Together, the findings demonstrate that laughter intensity does not overlap with loudness. They also highlight the necessity of further research on this complex dimension.
Abstract. Paper presented at the 5th Laughter Workshop, Paris, 27-28 September 2018: While laughter intensity is an important characteristic immediately perceivable for the listeners, empirical investigations of this construct are still scarce. Here, we explore the relationship between human judgments of laughter intensity and laughter acoustics. Our results show that intensity is predicted by multiple dimensions, including duration, loudness, pitch variables, and center of gravity. Controlling for loudness confirmed the robustness of these effects and revealed significant relationships between intensity and other features, such as harmonicity and voicing. Together, the findings demonstrate that laughter intensity does not overlap with loudness. They also highlight the necessity of further research on this complex dimension.
Participants who were told that another person got a better meal than they did liked their own meal less than if they were told that another person received either the same meal as they did
Food-based social comparisons influence liking and consumption. Jennifer S.Mills, Janet Polivy, Ayesha Iqbal. Appetite, April 26 2020, 104720. https://doi.org/10.1016/j.appet.2020.104720
Abstract: This study examined the effects of food-based social comparisons on hedonic ratings and consumption of a meal. Participants were randomly assigned to one of three experimental conditions in which they were led to believe that they got a worse meal, a better meal, or the same meal as another participant. They then tasted and rated their own meal. Subsequent liking and ad lib food consumption were measured. Participants who were told that another person got a better meal than they did (upward comparison) liked their meal less than if they were told that another person received either the same meal as they did or a worse meal (downward comparison). Similarly, participants who were in the upward comparison condition ate less food than if they were in the control or downward comparison conditions. Consumption was mediated by liking. The results suggest that being told that someone else is eating a meal that is higher or lower in hedonic value than one's own meal induces hedonic contrast and influences liking and consumption.
Keywords: Social comparisonFood hedonicsHedonic contrastEating behaviour
Abstract: This study examined the effects of food-based social comparisons on hedonic ratings and consumption of a meal. Participants were randomly assigned to one of three experimental conditions in which they were led to believe that they got a worse meal, a better meal, or the same meal as another participant. They then tasted and rated their own meal. Subsequent liking and ad lib food consumption were measured. Participants who were told that another person got a better meal than they did (upward comparison) liked their meal less than if they were told that another person received either the same meal as they did or a worse meal (downward comparison). Similarly, participants who were in the upward comparison condition ate less food than if they were in the control or downward comparison conditions. Consumption was mediated by liking. The results suggest that being told that someone else is eating a meal that is higher or lower in hedonic value than one's own meal induces hedonic contrast and influences liking and consumption.
Keywords: Social comparisonFood hedonicsHedonic contrastEating behaviour
Emotional empathy is more heritable than cognitive empathy; is affected by environment shared by siblings; found no find evidence for age differences in empathy heritability
The genetic and environmental origins of emotional and cognitive empathy: Review and meta-analyses of twin studies. Lior Abramson et al. Neuroscience & Biobehavioral Reviews, April 27 2020. https://doi.org/10.1016/j.neubiorev.2020.03.023
Highlights
• We meta-analyzed the twin literature of emotional and cognitive empathy.
• Emotional empathy is more heritable than cognitive empathy.
• Cognitive empathy as examined by tests is affected by environment shared by siblings.
• We did not find evidence for age differences in empathy heritability.
• We propose future directions to examine the processes behind genes-empathy relations.
Abstract: Empathy is considered a cornerstone of human social experience, and as such has been widely investigated from psychological and neuroscientific approaches. To better understand the factors influencing individual differences in empathy, we reviewed and meta-analyzed the behavioral genetic literature of emotional empathy- sharing others’ emotions (k=13), and cognitive empathy-understanding others’ emotions (k = 15), as manifested in twin studies. Results showed that emotional empathy is more heritable, 48.3% [41.3%-50.6%], than cognitive empathy, 26.9% [18.1%-35.8%]. Moreover, cognitive empathy as examined by performance tests was affected by the environment shared by family members, 11.9% [2.6%-21.0%], suggesting that emotional understanding is influenced, to some degree, by environmental factors that have similar effects on family members beyond their genetic relatedness. The effects of participants’ age and the method used to asses empathy on the etiology of empathy were also examined. These findings have implications for understanding how individual differences in empathy are formed. After discussing these implications, we suggest theoretical and methodological future research directions that could potentially elucidate the relations between genes, brain, and empathy.
Highlights
• We meta-analyzed the twin literature of emotional and cognitive empathy.
• Emotional empathy is more heritable than cognitive empathy.
• Cognitive empathy as examined by tests is affected by environment shared by siblings.
• We did not find evidence for age differences in empathy heritability.
• We propose future directions to examine the processes behind genes-empathy relations.
Abstract: Empathy is considered a cornerstone of human social experience, and as such has been widely investigated from psychological and neuroscientific approaches. To better understand the factors influencing individual differences in empathy, we reviewed and meta-analyzed the behavioral genetic literature of emotional empathy- sharing others’ emotions (k=13), and cognitive empathy-understanding others’ emotions (k = 15), as manifested in twin studies. Results showed that emotional empathy is more heritable, 48.3% [41.3%-50.6%], than cognitive empathy, 26.9% [18.1%-35.8%]. Moreover, cognitive empathy as examined by performance tests was affected by the environment shared by family members, 11.9% [2.6%-21.0%], suggesting that emotional understanding is influenced, to some degree, by environmental factors that have similar effects on family members beyond their genetic relatedness. The effects of participants’ age and the method used to asses empathy on the etiology of empathy were also examined. These findings have implications for understanding how individual differences in empathy are formed. After discussing these implications, we suggest theoretical and methodological future research directions that could potentially elucidate the relations between genes, brain, and empathy.
Why are Women More Religious than Men? Do Risk Preferences and Genetic Risk Predispositions Explain the Gender Gap?
Why are Women More Religious than Men? Do Risk Preferences and Genetic Risk Predispositions Explain the Gender Gap? YI LI ROBERT WOODBERRY HEXUAN LIU GUANG GUO. Journal for the Scientific Study of Religion, April 23 2020 https://doi.org/10.1111/jssr.12657
Abstract: Risk preference theory argues that the gender gap in religiosity is caused by greater female risk aversion. Although widely debated, risk preference theory has been inadequately tested. Our study tests the theory directly with phenotypic and genetic risk preferences in three dimensions—general, impulsive, and sensation‐seeking risk. Moreover, we examine whether the effects of different dimensions of risk preferences on the gender gap vary across different dimensions of religiosity. We find that general and impulsive risk preferences do not explain gender differences in religiosity, whereas sensation‐seeking risk preference makes the gender gap in self‐assessed religiousness and church attendance insignificant, but not belief in God, prayer, or importance of religion. Genetic risk preferences do not remove any of the gender gaps in religiosity, suggesting that the causal order is not from risk preference to religiosity. Evidence suggests that risk preferences are not a strong predictor for gender differences in religiosity.
Abstract: Risk preference theory argues that the gender gap in religiosity is caused by greater female risk aversion. Although widely debated, risk preference theory has been inadequately tested. Our study tests the theory directly with phenotypic and genetic risk preferences in three dimensions—general, impulsive, and sensation‐seeking risk. Moreover, we examine whether the effects of different dimensions of risk preferences on the gender gap vary across different dimensions of religiosity. We find that general and impulsive risk preferences do not explain gender differences in religiosity, whereas sensation‐seeking risk preference makes the gender gap in self‐assessed religiousness and church attendance insignificant, but not belief in God, prayer, or importance of religion. Genetic risk preferences do not remove any of the gender gaps in religiosity, suggesting that the causal order is not from risk preference to religiosity. Evidence suggests that risk preferences are not a strong predictor for gender differences in religiosity.
Casual sex is increasingly socially acceptable, but negative stereotypes about women remain; in this paper, both men & women stereotype women (but not men) who have casual sex as having low self-esteem
Krems, Jaimie, Ahra Ko, Jordan W. Moon, and Michael E. W. Varnum, PhD. 2020. “Lay Beliefs About Gender and Sexual Behavior: First Evidence for a Pervasive, Robust (but Seemingly Unfounded) Stereotype.” PsyArXiv. April 27. psyarxiv.com/rc2d3
Abstract: Although casual sex is increasingly socially acceptable, negative stereotypes toward women pursuing casual sex appear to remain pervasive. Specifically, a common trope in media (e.g., television, film) is that such women have low self-esteem. Despite robust work on prejudice against women who engage in casual sex, little empirical work investigates the lay theories individuals hold about such women. Across six experiments with US participants (N = 1,469), we find that both men and women stereotype women (but not men) who have casual sex as having low self-esteem. This stereotype is held explicitly and semi-implicitly, not driven by individual differences in religiosity, conservatism, or sexism, is mediated by inferences that women having casual sex are unsatisfied with their mating strategy, yet persists when these women are explicitly described as choosing to have casual sex. Finally, it appears unfounded; across experiments, these same participants’ sexual behavior is uncorrelated with their own self-esteem.
Abstract: Although casual sex is increasingly socially acceptable, negative stereotypes toward women pursuing casual sex appear to remain pervasive. Specifically, a common trope in media (e.g., television, film) is that such women have low self-esteem. Despite robust work on prejudice against women who engage in casual sex, little empirical work investigates the lay theories individuals hold about such women. Across six experiments with US participants (N = 1,469), we find that both men and women stereotype women (but not men) who have casual sex as having low self-esteem. This stereotype is held explicitly and semi-implicitly, not driven by individual differences in religiosity, conservatism, or sexism, is mediated by inferences that women having casual sex are unsatisfied with their mating strategy, yet persists when these women are explicitly described as choosing to have casual sex. Finally, it appears unfounded; across experiments, these same participants’ sexual behavior is uncorrelated with their own self-esteem.
Those who acted to benefit others were seen as egalitarian and less selfish, although expressing pride strongly overturned these judgments
McLatchie, Neil, and Jared Piazza. 2020. “The Challenge of Expressing Pride in Moral Achievements: The Advantage of Joy and Vicarious Pride.” PsyArXiv. April 27. psyarxiv.com/9f8pb
Abstract: Recent findings suggest bodily expressions of pride communicate a person is self-interested and meritocratic. Across two studies (combined N=721), we investigated whether these implications retain when pride is expressed with regards to moral achievements where the activity has benefited others. In Study 1, achievers that attained self-benefiting, competence-based achievements were judged to be self-interested and meritocratic, and expressing pride somewhat enhanced these evaluations. By contrast, those who acted to benefit others were seen as egalitarian and less selfish, although expressing pride strongly overturned these judgments. Study 2 replicated these findings and found that expressions of joy following a moral achievement, and pride expressed by a companion, enhanced the do-gooder’s perceived status without reducing attributions of egalitarianism. Our findings highlight the costs of displaying moral pride, but point to joy and vicarious pride as promising alternative routes for circumventing these costs. Datasets and analysis scripts are available at: https://osf.io/ra3gy/?view_only=5329461bfda84c0bb8c34df967d98398.
Abstract: Recent findings suggest bodily expressions of pride communicate a person is self-interested and meritocratic. Across two studies (combined N=721), we investigated whether these implications retain when pride is expressed with regards to moral achievements where the activity has benefited others. In Study 1, achievers that attained self-benefiting, competence-based achievements were judged to be self-interested and meritocratic, and expressing pride somewhat enhanced these evaluations. By contrast, those who acted to benefit others were seen as egalitarian and less selfish, although expressing pride strongly overturned these judgments. Study 2 replicated these findings and found that expressions of joy following a moral achievement, and pride expressed by a companion, enhanced the do-gooder’s perceived status without reducing attributions of egalitarianism. Our findings highlight the costs of displaying moral pride, but point to joy and vicarious pride as promising alternative routes for circumventing these costs. Datasets and analysis scripts are available at: https://osf.io/ra3gy/?view_only=5329461bfda84c0bb8c34df967d98398.
Monday, April 27, 2020
Sweet taste experience improves prosocial intentions and attractiveness ratings
Sweet taste experience improves prosocial intentions and attractiveness ratings. Michael Schaefer, Anne Reinhardt, Eileen Garbow & Deborah Dressler. Psychological Research (2020). https://rd.springer.com/article/10.1007/s00426-020-01336-x
Abstract: Taste-related terms such as bitter or sweet are often used to describe people’s behavior. For example, sweetness metaphors are often used when giving nicknames for romantic partners or when characterizing a friendly person. Previous studies have suggested that sweet taste may be linked to prosocial behavior. Examining a total of 517 participants, we here demonstrate that experiencing sweet taste also seems to have an impact on subsequent attractiveness ratings of faces. Participants were asked to rate pictures of young people and of art. Before this task, they were primed either with sweet candies or with salty snacks. Results revealed that sweet taste increased subsequent attractiveness ratings of faces. In addition, results confirmed earlier findings that sweet taste affected prosocial behavior. Our results suggest that sweetness seems to be more than a mere linguistic metaphor; it influences prosocial behavior as well as attractiveness ratings of faces. We discuss the results with recent findings of physical-to-psychological links to certain figures in speech.
Abstract: Taste-related terms such as bitter or sweet are often used to describe people’s behavior. For example, sweetness metaphors are often used when giving nicknames for romantic partners or when characterizing a friendly person. Previous studies have suggested that sweet taste may be linked to prosocial behavior. Examining a total of 517 participants, we here demonstrate that experiencing sweet taste also seems to have an impact on subsequent attractiveness ratings of faces. Participants were asked to rate pictures of young people and of art. Before this task, they were primed either with sweet candies or with salty snacks. Results revealed that sweet taste increased subsequent attractiveness ratings of faces. In addition, results confirmed earlier findings that sweet taste affected prosocial behavior. Our results suggest that sweetness seems to be more than a mere linguistic metaphor; it influences prosocial behavior as well as attractiveness ratings of faces. We discuss the results with recent findings of physical-to-psychological links to certain figures in speech.
Social class predicts visual perspective taking: Higher-class individuals made more errors than lower-class individuals in a task which requires participants to assume the visual perspective of another person
Social Class Predicts Emotion Perception and Perspective-Taking Performance in Adults. Pia Dietze, Eric D. Knowles. Personality and Social Psychology Bulletin, April 27, 2020. https://doi.org/10.1177/0146167220914116
Abstract: “Theory of Mind” (ToM; people’s ability to infer and use information about others’ mental states) varies across cultures. In four studies (N = 881), including two preregistered replications, we show that social class predicts performance on ToM tasks. In Studies 1A and 1B, we provide new evidence for a relationship between social class and emotion perception: Higher-class individuals performed more poorly than their lower-class counterparts on the Reading the Mind in the Eyes Test, which has participants infer the emotional states of targets from images of their eyes. In Studies 2A and 2B, we provide the first evidence that social class predicts visual perspective taking: Higher-class individuals made more errors than lower-class individuals in the Director Task, which requires participants to assume the visual perspective of another person. Potential mechanisms linking social class to performance in different ToM domains, as well as implications for deficiency-centered perspectives on low social class, are discussed.
Keywords: social class, culture, theory of mind, Director Task, Reading the Mind in the Eyes Test
Abstract: “Theory of Mind” (ToM; people’s ability to infer and use information about others’ mental states) varies across cultures. In four studies (N = 881), including two preregistered replications, we show that social class predicts performance on ToM tasks. In Studies 1A and 1B, we provide new evidence for a relationship between social class and emotion perception: Higher-class individuals performed more poorly than their lower-class counterparts on the Reading the Mind in the Eyes Test, which has participants infer the emotional states of targets from images of their eyes. In Studies 2A and 2B, we provide the first evidence that social class predicts visual perspective taking: Higher-class individuals made more errors than lower-class individuals in the Director Task, which requires participants to assume the visual perspective of another person. Potential mechanisms linking social class to performance in different ToM domains, as well as implications for deficiency-centered perspectives on low social class, are discussed.
Keywords: social class, culture, theory of mind, Director Task, Reading the Mind in the Eyes Test
We overestimate the effectiveness of a completely inefficacious drug; diseases that resolve spontaneously boost overestimations; overestimations remain even when participants consider all evidence available
Diseases that resolve spontaneously can increase the belief that ineffective treatments work. Fernando Blanco, Helena Matute. Social Science & Medicine. April 25 2020, 113012. https://doi.org/10.1016/j.socscimed.2020.113012
Highlights
• Participants overestimate the effectiveness of a completely inefficacious drug.
• Diseases that resolve spontaneously boost overestimations of effectiveness.
•Overestimations remain even when participants consider all evidence available.
Abstract
Rationale: Self-limited diseases resolve spontaneously without treatment or intervention. From the patient's viewpoint, this means experiencing an improvement of the symptoms with increasing probability over time. Previous studies suggest that the observation of this pattern could foster illusory beliefs of effectiveness, even if the treatment is completely ineffective. Therefore, self-limited diseases could provide an opportunity for pseudotherapies to appear as if they were effective.
Objective: In three computer-based experiments, we investigate how the beliefs of effectiveness of a pseudotherapy form and change when the disease disappears gradually regardless of the intervention.
Methods: Participants played the role of patients suffering from a fictitious disease, who were being treated with a fictitious medicine. The medicine was completely ineffective, because symptom occurrence was uncorrelated to medicine intake. However, in one of the groups the trials were arranged so that symptoms were less likely to appear at the end of the session, mimicking the experience of a self-limited disease. Except for this difference, both groups received similar information concerning treatment effectiveness.
Results: In Experiments 1 and 2, when the disease disappeared progressively during the session, the completely ineffective medicine was judged as more effective than when the same information was presented in a random fashion. Experiment 3 extended this finding to a new situation in which symptom improvement was also observed before the treatment started.
Conclusions: We conclude that self-limited diseases can produce strong overestimations of effectiveness for treatments that actually produce no effect. This has practical implications for preventative and primary health services. The data and materials that support these experiments are freely available at the Open Science Framework (https://bit.ly/2FMPrMi)
Keywords: Cognitive biasTreatment effectivenessPseudotherapyPatients' beliefsCausality bias
Highlights
• Participants overestimate the effectiveness of a completely inefficacious drug.
• Diseases that resolve spontaneously boost overestimations of effectiveness.
•Overestimations remain even when participants consider all evidence available.
Abstract
Rationale: Self-limited diseases resolve spontaneously without treatment or intervention. From the patient's viewpoint, this means experiencing an improvement of the symptoms with increasing probability over time. Previous studies suggest that the observation of this pattern could foster illusory beliefs of effectiveness, even if the treatment is completely ineffective. Therefore, self-limited diseases could provide an opportunity for pseudotherapies to appear as if they were effective.
Objective: In three computer-based experiments, we investigate how the beliefs of effectiveness of a pseudotherapy form and change when the disease disappears gradually regardless of the intervention.
Methods: Participants played the role of patients suffering from a fictitious disease, who were being treated with a fictitious medicine. The medicine was completely ineffective, because symptom occurrence was uncorrelated to medicine intake. However, in one of the groups the trials were arranged so that symptoms were less likely to appear at the end of the session, mimicking the experience of a self-limited disease. Except for this difference, both groups received similar information concerning treatment effectiveness.
Results: In Experiments 1 and 2, when the disease disappeared progressively during the session, the completely ineffective medicine was judged as more effective than when the same information was presented in a random fashion. Experiment 3 extended this finding to a new situation in which symptom improvement was also observed before the treatment started.
Conclusions: We conclude that self-limited diseases can produce strong overestimations of effectiveness for treatments that actually produce no effect. This has practical implications for preventative and primary health services. The data and materials that support these experiments are freely available at the Open Science Framework (https://bit.ly/2FMPrMi)
Keywords: Cognitive biasTreatment effectivenessPseudotherapyPatients' beliefsCausality bias
5.3. General discussion
Pseudotherapies are drugs or other types of treatment that produce no beneficial effect on the likelihood of improving from a disease, such that the contingency between using the pseudotherapy and observing an improvement is null, once potential placebo effects are discounted (Hellmuth et al., 2019). Nevertheless, certain situations can induce illusory beliefs of effectiveness, even for pseudotherapies that are completely ineffective. In particular, diseases with high likelihood of spontaneous remission, P(O), can result in strong overestimations of effectiveness (Matute et al., 2019). Yet in most experiments the P(O) is set to a fixed level during the whole session (Blanco et al., 2014; Chow et al., 2019), with only a few studies investigating the effect of changing the P(O) levels as the session proceeds. In this context, self-limited diseases are of interest because, given their natural evolution, they usually produce a pattern of steady increasing probability of remission. According to previous research, an increasing pattern of P(O) could in principle promote strong illusions of effectiveness in a null contingency setting (Ejova et al., 2013; Matute, 1995), though sometimes the opposite result (e.g., accurate estimations of non-effectiveness) has been reported (Langer and Roth, 1975). Additionally, none of these previous studies investigated the effect of increasing patterns of P(O) in a medical context. Testing the effect of increasing P(O) using a medical context is important, because this pattern, which is common in self-limited diseases, could represent one of the gaps through which pseudotherapies infiltrate our societies. Given that self-limited diseases are common, if they do favor the use of pseudotherapy by promoting the illusory belief in their effectiveness, then many people could turn to these pseudotherapies uncritically whenever they suffer a more serious health problem.
Our three behavioral experiments align in documenting evidence for the overestimation of effectiveness in self-limited diseases. In this regard, they coincide with results reported in non-medical scenarios (Ejova et al., 2013; Matute, 1995), and contradict a classic study (Langer and Roth, 1975). Nevertheless, we note that Langer and Roth's study tapped on a chance situation (coin toss) in which no improvement should be expected with time or practice, which could help to interpret the discrepancy. Additionally, in Ejova et al.'s study, the interpretation of the situation as chance-based was measured and controlled for in the analysis.
In our experiments, trial-by-trial judgments increased gradually with the P(O) in the self-limited group (see Fig. 4, Fig. 6). As a result, the participants in this group ended their training session with a strong belief of effectiveness. This contrasts with participants in the control group, who showed a significantly smaller illusion of effectiveness. A possible interpretation is that people assume that patterns of gradual improvement are the typically expected ones when a treatment is actually working. That is, people rarely attribute these gradually improving patterns to the natural course of a self-limited disease, and instead they look for a potential explanation, which in this case is the treatment.
Experiment 2 replicated the results of Experiment 1 (Fig. 4), differing only on the type of response scale used (unidirectional, instead of bidirectional). Although contingency can take on either positive or negative values, it is not obvious how to interpret a negative value in this particular context — a treatment for a disease. Consequently, most previous studies used a unidirectional scale (from 0, ineffective, to 100, perfectly effective). Here we obtain the same results irrespective of the scale. This speaks of the robustness of the general result: regardless of the type of response scale, the tendency to overestimate the effectiveness was higher in the group that mirrored the self-limited disease, compared with the control group.
In Experiment 3, we modeled a self-limited disease in a different way: in addition to the null contingency between taking the treatment and observing a remission of the symptoms, we showed the symptom-occurrence baseline before the treatment starts. This should allow participants to fairly compare the P(O) before and after the treatment, even under the assumption that trials are dependent on each other — that taking the drug on one day can help to improve health days later. Even with this information available, participants overestimated the effectiveness of the pseudomedicine when the pattern of P(O) was increasing, as compared to the control group (Fig. 6). Thus, a different design, resting on different assumptions than those in Experiments 1 and 2, still produced similar results.
Experiment 3 presents an interesting question, as it is designed to work under the assumption of non-independence between trials. Most contingency learning experiments describe trials that can be naturally interpreted as mutually independent: for example, it is common to present a sequence of trials arranged in random order, each one corresponding to a different individual patient (Blanco et al., 2014; Blanco and Matute, 2019). Thus, it is unlikely that participants assume that treating one patient could affect subsequent patients. This was probably the case in Ejova et al.'s (2013) experiments, and it certainly was in the case of Matute (1995) and Langer and Roth (1975) studies. Under the assumption of trial independence, it is easy to reproduce the overestimation of effectiveness when a disease has a high probability of spontaneous remission (Blanco et al., 2014; Blanco and Matute, 2019). However, in our current procedure, it is possible to interpret the training as a time-series with dependencies between trials: if the patient takes the medicine today, the effects can be seen some days later. As we have argued, assuming that trials can be mutually dependent in this fashion has important consequences, the main one being that contingency, computed as the difference between P(O|C) and P(O|∼C), stops being a useful index. This is a possibility that has been largely overlooked in most research in human contingency learning, with few exceptions (Bramley et al., 2015). In Experiment 3, we replicated the overestimation of effectiveness in these conditions, which extends the results of Ejova et al. (2013) to a new scenario. Future studies could deepen further in the implications of assuming dependency between observations.
Additionally, we collected information about the perceived effectiveness in two moments: on each trial (trial-by-trial judgments) and after the whole session (global judgment). It is well known that trial-by-trial judgments typically show recency effects: they are heavily affected by the information presented in the current or immediately previous trials (Matute et al., 2002). In global judgments, we asked participants to take into account all the information they had seen from the beginning of the session, a strategy that often results in the participants being able to integrate the information from the different phases (Matute et al., 2002). It would be useful to know whether people can be capable of integrating all the information and overcome their biases just by asking them to do so. Thus, we expected that global judgments in the self-limited group would not be so strongly influenced by the last part of the training session, which featured a very high P(O). This should probably reduce the illusion and blur the differences between the groups, given that they received exactly the same frequencies of trials when considering the overall session. However, global judgments in our experiments showed a familiar overestimation trend, with the self-limited group reporting stronger beliefs of effectiveness than the control group, although the effect was less pronounced than in trial-by-trial judgments (in Experiment 1, the difference between groups in the global judgments was just marginal). Therefore, this result is in line with previous studies showing that participants can better integrate all the information seen during the training at the end of the session if requested to do so, while trial-by-trial judgments are strongly affected by the most recent piece of information (Matute et al., 2002). Yet, note that the effect of increasing the P(O) during the training session survives despite the explicit instruction to try to avoid being too biased by the last part of the session. Consequently, the result highlights the view that self-limited diseases can potentially produce strong and resistant beliefs of effectiveness.
There were additional judgments in our task. First, through the Alternative Cause judgments, participants could report whether they felt that outcome occurrences (e.g., symptom remissions) could be attributed to causes other than the pseudomedicine. In Experiments 1 and 2, the results do not indicate any significant difference between groups. People do not tend to attribute health improvement instances to any unspecified alternative cause, irrespective of the group (average answers around 6 out of 10 points). In Experiment 3, in contrast, we found that participants in the self-limited group tended to judge that symptom remissions were due to the treatment more often than participants in the control group, which is in line with the predictions.
Second, our participants estimated the two conditional probabilities, P(O|C) and P(O|∼C) — probability of symptom remission when taking the medicine versus when not taking the medicine. In Experiments 1 and 2, P(O|C) was systematically more overestimated than P(O|∼C). The latter result is compatible with the presence of an illusion of causality, or overestimation of the effectiveness of the drug (Blanco and Matute, 2019), that exists in all groups, since participants seem to judge that improvements are generally more likely when one takes the medicine than when one does not. In fact, the difference between these two probability estimations (which is analogous to computing an estimated contingency) correlates significantly with effectiveness ratings in all six groups across the three experiments. In addition, in Experiment 3 not only this tendency to overestimate P(O|C) was found, but it was significantly stronger in the self-limited group, where effectiveness was judged higher, which also reinforces the idea that people in this group developed strong beliefs of effectiveness.
We can only speculate as to why the additional judgments (global judgment, Alternative Cause judgment, conditional probability judgments) seem to have captured stronger effects in Experiment 3 than in Experiments 1 and 2. One of the most evident reasons is that, by separating the outcome base-rate training in one phase, instead of presenting it in intermixed trials, Experiment 3 made it much easier to grasp the base-rate to which compare the P(O) once the treatment starts. Another, somewhat more trivial, reason is that we started and ended the training using more extreme values of P(O), namely 0 and 1, which might create the impression that the medicine works at the end of the session.
When interpreting Experiment 3, one should be aware that the design does not perfectly control all potential extraneous variables. Of special relevance is the difference in the P(O) during Phase 2 between the two groups: that is, the probability of symptom remission is overall higher in this phase for participants in the self-limited group, P(O) = 0.83, compared to participants in the control group, P(O) = 0.50. This difference could contribute to the effect, as we know from previous literature that higher P(O) levels typically produce higher judgments, such as with outcome-density bias (Chow et al., 2019; Musca et al., 2010). Future studies could try to address this problem by including additional controls. For instance, it would be possible to add a stable, high P(O) control condition, in which symptom remissions appear as often as in the last part of the self-limited group. We note, however, that such control would still not be perfect, as it is impossible to fix all relevant parameters (outcome probability, contingency, number of trials, etc.) while one of the groups remains stable and the other increases in P(O).
These experiments can also help us shed some light on the mechanisms underlying the overestimation of causality more generally. Traditionally, these illusory beliefs have been explained by invoking differential “cell-weighting” processes (Kao and Wasserman, 1993). That is, of the four cells in the contingency matrix of Fig. 1, it is possible that people pay more attention to those events that are more salient — typically, cells a, or medicine-remission events — or give them more importance when forming the belief. This proposal could explain both the present experiments as well as other instances of overestimation of effectiveness: even if the number of type a trials (medicine-remission) is the same as type c trials (no medicine-remission), people would weigh the former more heavily, thus strengthening the belief of effectiveness beyond the provided data. Concerning this possibility, we collected conditional probability judgments in addition to effectiveness judgments, and through the three experiments, these conditional probability estimations seem to show a tendency to overestimate the probability of remission conditional on the medicine, compared to when no medicine was taken, such that P(O|C) > P(O|∼C), especially in those individuals who developed stronger beliefs of effectiveness. This could be interpreted as an increased attention/importance given to medicine-present trials, which is in line with previous experiments investigating cell-weighting mechanisms (Kao and Wasserman, 1993).
5.4. Limitations
One obvious shortcoming of our procedure is the limited ecological validity, given that the situation is artificial, and participants must imagine how they would think in real life contexts. On the other hand, it seems difficult to experimentally study these processes of change in the beliefs of effectiveness with real treatments and outcomes. We believe that it would not be feasible for practical and ethical reasons, so our computer-based approach remains a valid candidate.
Another limitation of this research is that only two conditions were compared in each experiment: an increasing pattern of P(O) versus a stable pattern of P(O). Thus, we are not examining the potential role of consistency, but we are always comparing one group in which the outcome changes with another group in which it does not change. A more systematic approach would have included additional conditions: decreasing pattern of P(O), U-shaped pattern, etc. Some of these conditions are studied in previous experiments (Ejova et al., 2013; Matute, 1995), but, as they do not correspond well to any meaningful real situation in actual medicine usage, we decided to keep our experiments as simple as possible, by just comparing self-limited diseases with stable diseases. Future studies could put to test additional conditions.
In addition, this research rests on the assumption that the formation of effectiveness beliefs during the experimental session is due to basic processes (e.g., contingency learning) that are general-purpose, and work in similar ways for all people. Thus, we have not considered the potential impact of individual differences based on educational level, age, or attitudes, for example. This could be an interesting field of study for future research, as some studies have suggested that prior beliefs and attitudes can in fact modulate the formation of causal knowledge, leading to overestimations of causality similar to those reported here (Blanco et al., 2018). Moreover, it would be highly interesting to investigate whether unsupported beliefs of effectiveness actually translate into differences in treatment use, and whether this effect is further modulated by individual factors that could help us identify particularly vulnerable individuals or situations.
Homophobia among adolescents & adults in Switzerland & Germany; Males, youths with a migration background & religious respondents have significantly stronger prejudices; upbringing has small influence
Dirk Baier, Maria Kamenowski, Verbreitung und Einflussfaktoren von Homophobie unter Jugendlichen und Erwachsenen. Befragungsbefunde aus der Schweiz und Deutschland (Spread and influence of homophobia among adolescents and adults. Survey findings from Switzerland and Germany). RPsych Rechtspsychologie, Volume 6 (2020), Issue 1, pp 5-35. https://doi.org/10.5771/2365-1083-2020-1-5
Automatic translation:
Abstract: Homophobia, i. e. the devaluation of non-heterosexual people, exists both in Switzerland and in Germany. On the one hand, the article examines the question of how prevalent homophobic attitudes are among the youth and adult population. On the other hand, factors influencing these attitudes are analysed across age groups and countries. Three samples are used for the analyses. The results show that between 10.3 % and 29.9 % of respondents agree with homophobic attitudes, depending on the item of measuring instruments used; same-sex marriages in particular are rejected by respondents. In addition, it can be concluded that male respondents, youths with a migration background and religious respondents (regardless of their religious affiliation) have significantly stronger prejudices against homosexuals.
Automatic translation:
Abstract: Homophobia, i. e. the devaluation of non-heterosexual people, exists both in Switzerland and in Germany. On the one hand, the article examines the question of how prevalent homophobic attitudes are among the youth and adult population. On the other hand, factors influencing these attitudes are analysed across age groups and countries. Three samples are used for the analyses. The results show that between 10.3 % and 29.9 % of respondents agree with homophobic attitudes, depending on the item of measuring instruments used; same-sex marriages in particular are rejected by respondents. In addition, it can be concluded that male respondents, youths with a migration background and religious respondents (regardless of their religious affiliation) have significantly stronger prejudices against homosexuals.
Sunday, April 26, 2020
Heritability of Bullying and Victimization in Children and Adolescents: Moderation by the KiVa Antibullying Program
Heritability of Bullying and Victimization in Children and Adolescents: Moderation by the KiVa Antibullying Program. Ada Johansson et al. Journal of Clinical Child & Adolescent Psychology,
Mar 16 2020. https://doi.org/10.1080/15374416.2020.1731820
ABSTRACT
Objective: Bullying affects approximately a quarter of schoolchildren and is associated with numerous adverse outcomes. Although distinct risk factors for bullying and victimization have been identified, few studies have investigated the genetic and environmental underpinnings of bullying and victimization. The aims of this study were twofold: first, to examine the contributions of genetic and environmental factors to bullying and victimization, and second, to analyze whether the KiVa antibullying program moderated the magnitude of these contributions by comparing estimates derived from the KiVa versus control groups.
Method: The sample comprised students from schools that participated in the evaluation of the KiVa antibullying program in Finland during 2007–2009. Bullying and victimization were measured using peer nominations by classmates. The sample for the twin analyses comprised of 447 twins (107 monozygotic and 340 dizygotic twins) aged 7–15.
Results: Genetic contributions accounted for 62% and 77% of the variance in bullying and in victimization at pre-intervention, respectively. There was a post-intervention difference in the overall role of genetic and environmental contributions between the intervention and the control group for bullying and victimization, with non-shared environmental effects playing a lesser role (and genes a larger role) in the intervention than in the control group context.
Conclusions: This study replicates previous findings on the genetic underpinnings of both bullying and victimization, and indicates that a school-based antibullying program reduces the role of non-shared environmental factors in bullying and victimization. The results indicate that prevention and intervention efforts need to target both environmental and (heritable) individual level factors to maximize effectiveness.
Mar 16 2020. https://doi.org/10.1080/15374416.2020.1731820
ABSTRACT
Objective: Bullying affects approximately a quarter of schoolchildren and is associated with numerous adverse outcomes. Although distinct risk factors for bullying and victimization have been identified, few studies have investigated the genetic and environmental underpinnings of bullying and victimization. The aims of this study were twofold: first, to examine the contributions of genetic and environmental factors to bullying and victimization, and second, to analyze whether the KiVa antibullying program moderated the magnitude of these contributions by comparing estimates derived from the KiVa versus control groups.
Method: The sample comprised students from schools that participated in the evaluation of the KiVa antibullying program in Finland during 2007–2009. Bullying and victimization were measured using peer nominations by classmates. The sample for the twin analyses comprised of 447 twins (107 monozygotic and 340 dizygotic twins) aged 7–15.
Results: Genetic contributions accounted for 62% and 77% of the variance in bullying and in victimization at pre-intervention, respectively. There was a post-intervention difference in the overall role of genetic and environmental contributions between the intervention and the control group for bullying and victimization, with non-shared environmental effects playing a lesser role (and genes a larger role) in the intervention than in the control group context.
Conclusions: This study replicates previous findings on the genetic underpinnings of both bullying and victimization, and indicates that a school-based antibullying program reduces the role of non-shared environmental factors in bullying and victimization. The results indicate that prevention and intervention efforts need to target both environmental and (heritable) individual level factors to maximize effectiveness.
Discussion
The present study aimed at examining the magnitude of genetic and environmental contributions to bullying and victimization, in a Finnish sample aged 7–15. In addition, the aim was to test whether the KiVa antibullying program would moderate these contributions. As expected, we found significant and substantial genetic contribution for both bullying and victimization in general, as well as a moderation through the antibullying intervention program of the ratio between genetic and non-shared environmental factors.
Broad sense heritability (H2) for bullying was estimated at 62% (A = 23%, D = 39%) for pre-intervention, with non-shared environmental factors accounting for the rest of the variance. The dominance component has not been reported previously, however, twin analyses have limited statistical power to distinguish between additive and non-additive genetic effects, and estimates of the broad sense heritability are more stable (Eaves, 1972). In that sense, the broad sense heritability is very similar to the previous findings by Ball et al. (2008; 61% heritability for bullying), Veldkamp et al. (2019; ~70%), and Dunbar (2018; 55%), even though different informants were used (i.e. combined parents’ and teachers’ ratings in Ball et al., 2008, and teachers’ ratings in Veldkamp et al., 2019). The present study is the first one to have estimated the heritability of bullying using peer nominations. The heritability estimates for bullying are in line with those found for antisocial behavior and aggression more generally (Brendgen et al., 2008; Burt, 2009; Polderman et al., 2015; Porsch et al., 2016).
Broad sense heritability for pre-intervention victimization scores was quite substantial at 77% (A = 50%, D = 27%), with non-shared environmental influences accounting for the rest of the variance. Again, this estimate is in the range of several previous studies (73% for Ball et al., 2008; 71–77% for Bowes et al., 2013; 70% for Connolly & Beaver, 2016; 67% for Törn et al., 2015; ~65% for Veldkamp et al., 2019). Other studies have reported lower heritability estimates: Brendgen et al. (2008) estimated the heritability of victimization to 0% in one study, and 26% in a later study (Brendgen et al., 2011), and Shakoor et al. (2015), Silberg et al. (2016), and Dunbar (2018) reported heritabilities of 35%, 45% and 48%, respectively. However, these variations could be accounted for by a variety of reasons. For instance, both Eastman et al. (2018) and Veldkamp et al. (2019) found that heritability estimates vary depending on the type of victimization; they found higher heritabilities for physical (42% and 70%, respectively) versus social/relational (0% and 55%) and property-related victimization (0%, only in Eastman et al., 2018). In addition, the twin studies also seem to differ, for example, with regards to informants used and age of participants. The use of single informants may give rise to unstable or low estimates (due to larger measurement error), especially for self-ratings in younger children. When multiple informants were used in a latent model of peer victimization and rejection, a significant and substantial contribution of genes was seen for twins from Kindergarten to grade 4 (H2 = 73–94%; Boivin et al., 2013a), which is in line with our results. Eastman et al. (2018) compared the genetic and environmental estimates derived from children (ages 9–14), versus adolescents (ages 15–20), and found differences in the magnitude and structure of genetic influences. The genetic contribution to victimization indicate that heritable characteristics in the child could evoke a negative reaction from peers and thus play a role in the likelihood of being bullied by others, a form of evocative rGE (Boivin et al., 2013a). Such characteristics could include reactive-impulsive aggression (Boivin et al., 2013b), but also depression, ADHD, risk taking, high BMI or low intelligence, as Schoeler et al. (2019) recently showed, through a polygenic risk score approach, that genetic risks for these characteristics were related to victimization. These modest associations need replications, as well as confirming evidence that they work through the mediating role of the putative child characteristics. Further evidence for the rGE hypothesis is also found in twin studies indicating partial overlap between the genes influencing victimization and those for social anxiety (Silberg et al., 2016), as well as depression/anxiety (Connolly & Beaver, 2016).
Significant genetic contributions to victimization and bullying were also found post-intervention, after pre-intervention levels were accounted for. This was true for both the intervention and the control group. Since pre-intervention levels were regressed out from the post-intervention levels, direct comparisons between heritability estimates between the time-points cannot be made. Crucial to the objective of the present study were the findings regarding the moderating role of the KiVa intervention. Moderation by the KiVa program would be indicated if the post-intervention estimates differed between the control and the intervention group after controlling for pre-intervention levels. This was true for both bullying and victimization. For both phenotypes, the general ADE pattern of estimates differed across groups (intervention vs control), essentially reflected by lower E-estimates in the intervention (bullying 42%, victimization 28%) compared to the control group (bullying 64%, victimization 63%), and thus leaving more room for genes to account for the remaining variance. The significantly smaller E-estimates in the intervention group could reflect a possible leveling out of environmental risk due to the KiVa intervention (e.g. through changing the behavior of bystanders and making bullying behavior less acceptable in the school setting), leaving a higher role to genetically influenced individual characteristics in that context. This pattern of findings is in line with the push hypothesis (Raine, 2002), which posits that genes will play a larger role in an environment freer of environmental risk factors. Evidence for such GxE findings have been found, for example, with respect to the moderating role of socioeconomic status on the genetic and environmental etiology of antisocial behavior (Tuvblad, Grann, & Lichtenstein, 2006) and the role of early adversity in physiological stress (Ouellet-Morin et al., 2008).
These results indicate the conditional nature of these environmental and genetic sources of individual differences, but they also point to the importance of providing contexts, through policies (e.g. early education) or intervention (i.e. KiVa), to create a more equitable social and learning environment for all children. When these interventions are successful in leveling out the environmental playing field, they may paradoxically identify individual factors, here genetic factors in the child, as more important for various outcomes. In doing so, they provide useful information in that they point to where the effort for change should be oriented. Specifically, even though the KiVa intervention is amongst the most effective antibullying interventions (Gaffney, Farrington, & Ttofi, 2019), it fails to stop all bullying. Our results indicate that genes play a significant role in accounting for post-intervention variance in bullying and victimization, and that the efficacy of the KiVa program might be enhanced by incorporating components targeting individual heritable characteristics. Previous research indicates that heritable individual characteristics that could evoke victimization from peers include mental health problems such as depression and anxiety (Connolly & Beaver, 2016; Schoeler et al., 2019; Silberg et al., 2016), ADHD, high BMI and low intelligence (Schoeler et al., 2019). Schoeler et al. (2019) suggested that one way to target such individual heritable characteristics with regards to victimization, could be to include components trying to reduce the stigma of mental health problems or other vulnerabilities such as high BMI, or to offer more support to children displaying internalizing or externalizing symptoms. Intervention components could either be universal (targeted at the entire school) such as in components aiming to change the environment to be less discriminatory (e.g., toward people with mental health problems, neuropsychological difficulties, or high BMI), or individual (e.g. support and/or interventions for students at risk). In addition, one should also keep in mind that interventions not specifically aimed at reducing bullying victimization or perpetration, but rather aimed at reducing characteristics that increase the risk for victimization or perpetration could, in turn, also reduce bullying.
With respect to bullying perpetration, less is known about the specific underlying heritable characteristics, but such could include, for example, callous-unemotional traits and/or conduct problems (Viding, Simmonds, Petrides, & Frederickson, 2009; Zych, Ttofi, & Farrington, 2019). It is important to identify at-risk children early, and intervene not only in the school context but also by means of parenting programs (Waller, Hyde, Klump, & Burt, 2018). Further research is needed to identify specific heritable characteristics related to both the risk of victimization and bullying, especially victimization and bullying that persists after intervention efforts. However, as we know that standard interventions are not helpful in all cases (see also Kaufman, Kretschmer, Huitsing, & Veenstra, 2018), school personnel should always follow up after taking action to stop bullying, check whether their intervention was helpful, and to take further action when needed.
A strength of this study is that bullying and victimization were measured with proportion scores derived from peer nominations. In addition to there being multiple reporters, classmates can be considered to be more up to date on what is happening in the school setting (Boivin et al., 2013a; Stassen Berger, 2007), than for instance teachers or parents. Another clear strength of our study is the RCT-design, which effectively controls for potential confounds such as those that might arise from unaccounted rGE. The participating schools can be considered representative of Finnish schools at the time of data collection. In addition, twins did not differ from non-twin individuals on bullying or victimization, suggesting that the results are generalizable to non-twin individuals.
A limitation is the relatively small sample size, especially with regards to the post-intervention comparison between the intervention and the control group. The pre-intervention estimates are likely more robust, as these used data from all twins. We decided to do separate analyses for the pre- and post-intervention data for two reasons. First, even though a multi-group approach is warranted for the post-intervention data, it was preferable to analyze the pre-intervention data in a single group for increased statistical power. Second, an extension of the Cholesky decomposition to a multivariate case (i.e. analyzing both pre- and post-intervention) is problematic in multi-group approaches (Neale, Røysamb, & Jacobson, 2006). A multivariate approach would, however, allow a comparison of the variance components between the time-points, and therefore, replication efforts with larger sample sizes finding a solution to the multivariate approach would be welcome. A possible limitation of the twin method is whether the equal environments assumption holds. It has, however, been tested in a number of studies and appears to be valid (e.g. Derks, Dolan, & Boomsma, 2006; Kendler, Neale, Kessler, Heath, & Eaves, 1993).
Concert, dance, theater, museums, libraries: The Humanities Make Our Lives Richer, Happier, and More Meaningful
Westgate, Erin C. 2020. “Art, Music, and Literature: Do the Humanities Make Our Lives Richer, Happier, and More Meaningful?.” PsyArXiv. April 25. doi:10.31234/osf.io/gsnzm
Abstract: For many, there is little more rewarding than the feeling of curling up with a good book, wandering a famous art gallery, or listening to a favorite musician perform live in front of an audience. But do the arts, music, and literature actually make our lives happier, richer, and more meaningful? We suggest they do. In this chapter, we review empirical evidence for the psychological benefits of the humanities, including art, music, and literature, and find that across a wide variety of samples, exposure and engagement is consistently linked to greater well-being. In particular, we suggest that the humanities may increase well-being directly by providing people with enjoyable, rich, and meaningful experiences, as well as indirectly by fostering skills and abilities that contribute to psychological well-being in the long-term. These approaches map onto two mechanisms: 1) direct affective benefits that create enjoyable, rich, and interesting experiences, and 2) indirect cognitive benefits, including social abilities and motivations that promote subjective well-being via interpersonal connection and self- and emotion-regulation. Art, music, and literature may not only provide temporary nourishment for a good life, but teach people lasting skills they can capitalize on to increase long-term well-being.
Abstract: For many, there is little more rewarding than the feeling of curling up with a good book, wandering a famous art gallery, or listening to a favorite musician perform live in front of an audience. But do the arts, music, and literature actually make our lives happier, richer, and more meaningful? We suggest they do. In this chapter, we review empirical evidence for the psychological benefits of the humanities, including art, music, and literature, and find that across a wide variety of samples, exposure and engagement is consistently linked to greater well-being. In particular, we suggest that the humanities may increase well-being directly by providing people with enjoyable, rich, and meaningful experiences, as well as indirectly by fostering skills and abilities that contribute to psychological well-being in the long-term. These approaches map onto two mechanisms: 1) direct affective benefits that create enjoyable, rich, and interesting experiences, and 2) indirect cognitive benefits, including social abilities and motivations that promote subjective well-being via interpersonal connection and self- and emotion-regulation. Art, music, and literature may not only provide temporary nourishment for a good life, but teach people lasting skills they can capitalize on to increase long-term well-being.
Facial width-to-height ratio was reliably negatively associated to how dominant, trustworthy, sociable, emotionally stable, responsible, confident, attractive, & intelligent appeared a woman
Durkee, Patrick, and Jessica D. Ayers. 2020. “Is Facial Width-to-height Ratio Reliably Associated with Social Inferences? A Large Cross-national Examination.” PsyArXiv. April 25. doi:10.31234/osf.io/tpngz
Abstract: Previous research suggests that facial width-to-height ratio (fWHR) may be associated with behavioral tendencies and social judgments. Mounting evidence against behavioral links, however, has led some researchers to invoke evolutionary mismatch to explain fWHR-based inferences. To examine whether such an explanation is needed, we leveraged a large cross-national dataset containing ratings of 120 faces on 13 fundamental social traits by raters across 11 world regions (N = 11,481). In the results of our preregistered analyses, we found mixed evidence for fWHR-based social judgments. Men’s fWHR was not reliably linked to raters’ judgments for any of the 13 trait inferences. In contrast, women’s fWHR was reliably negatively associated with raters’ judgments of how dominant, trustworthy, sociable, emotionally stable, responsible, confident, attractive, and intelligent women appeared, and positively associated with how weird women appeared. Because these findings do not follow from assumptions and theory guiding fWHR research, the underlying theoretical framework may need revising.
Abstract: Previous research suggests that facial width-to-height ratio (fWHR) may be associated with behavioral tendencies and social judgments. Mounting evidence against behavioral links, however, has led some researchers to invoke evolutionary mismatch to explain fWHR-based inferences. To examine whether such an explanation is needed, we leveraged a large cross-national dataset containing ratings of 120 faces on 13 fundamental social traits by raters across 11 world regions (N = 11,481). In the results of our preregistered analyses, we found mixed evidence for fWHR-based social judgments. Men’s fWHR was not reliably linked to raters’ judgments for any of the 13 trait inferences. In contrast, women’s fWHR was reliably negatively associated with raters’ judgments of how dominant, trustworthy, sociable, emotionally stable, responsible, confident, attractive, and intelligent women appeared, and positively associated with how weird women appeared. Because these findings do not follow from assumptions and theory guiding fWHR research, the underlying theoretical framework may need revising.
Saturday, April 25, 2020
The Genetic Inactivation of the Vomero-Nasal Organ in Primates Allows the Evolution of Same-Sex Sexual Behavior But Does Not Explain Homosexual Orientation in Humans
Camperio Ciani, A.S. The Genetic Inactivation of the Vomero-Nasal Organ in Primates Allows the Evolution of Same-Sex Sexual Behavior But Does Not Explain Homosexual Orientation in Humans. Arch Sex Behav, April 24 2020. https://doi.org/10.1007/s10508-020-01708-9
A variety of mammals, including primates, communicate
through pheromones, which are volatile chemical signals
produced by glands and detected through the vomero-nasal
organ (VNO). This manner of communication is effective
and fundamental for eliciting innate responses to locate
sexual partners and inducing sexual behavior. Pfau, Jordan,
and Breedlove, (2019) hypothesized that progressive
degeneration of a single-gene coding for pheromones receptors
in the VNO of mammals may have triggered a cascade
of functional and behavioral consequences that facilitated
the development of new modes of sexual communication,
including same-sex sexual behavior in primates and humans.
This hypothesis is compelling, testable, and heuristic.
In their Target Article, Pfau et al. (2019) suggest that, during
primate evolution, inactivation of the transient receptor
potential cation channel 2 (TRPC2) gene caused a shift from
strictly pheromonal-driven sexual behavior toward a more
flexible sexual response that allowed for occasional samesex
sexual behavior. In other words, a more flexible sexual
response to different and varied stimuli might have allowed
the use of sex, including same-sex sexual activity, in both
sexes, in contexts beyond reproduction such as dominance
displays, reconciliation, and appeasement (de Waal, 1989).
The main evidence in support of Pfau et al.’s (2019)
hypothesis comes from knock-out (KO) TRPC2 mice. Pfau
et al. found that this experimental strain of KO mice exhibits
delay development and altered intraspecific interactions such
as sex discrimination and male–male aggression (Leypold
et al., 2002; Stowers, Holy, Meister, Dulac, & Koentges,
2002). Most importantly, compared to wild mice strains,
adult male and female KO TRPC2 mice were observed to
engage in unprecedented levels of same-sex sexual behavior
including mounting and pelvic thrusting.
Comparing KO TRPC2 mice and Old World monkeys,
Pfau et al. (2019) furnish evidence that catarrhine primates,
which lack a VNO, also have a nonfunctional TRPC2 gene.
They argued that like KO TRPC2 mice, catarrhine primates
exhibit reduced aggressions and delayed development. Based
on these comparisons, they proposed that this TRPC2 single-
gene inactivation might explain not only the cause of
same-sex sexual behavior in nonhuman primates, but also the
cause of sexual orientation in humans. Further, they proposed
that the inactivation of the TRPC2 gene promoted a series
of behavioral and social transformation that are common in
domesticated animals and self-domesticated humans (Hare,
2017; Hare, Wobber, & Wrangham, 2012).
The primate data do not fit Pfau et al’s (2019) hypothesis
perfectly, however, and as the authors admit, there are some
prosimians (e.g., brown lemurs, Lemur fulvus, and sifakas,
Propitecus verreuxi; Bagemihl, 1999), as well as some New
World monkeys (e.g., common marmoset, Callitrix jacchus,
and Geoffroy’s tamarin, Saguinus geoffroyi) that have intact
TRPC2 genes and show same-sex sexual behavior (e.g.,
Manson, Perry, & Parish, 1997; Rothe, 1975). Conversely,
there are a number of Old World monkeys such as gibbons
and olive colobus (Procolobus verus) that lack a functional
TRPC2 gene, but have never been shown, in field observations,
to exhibit same-sex sexual behavior in either sexes.
However, these are minor exceptions, and in general Pfau
et al.’s hypothesis is supported by the primate data.
Pfau et al.’s (2019) hypothesis could also be tested in
other mammals known to have same-sex sexual behavior.
For example, dogs (Canis spp.) are known to have same-sex
sexual behavior both in females (Beach, Rogers, & LeBoeuf,
1968) and in males (Dagg, 1984), and at the same time they
are macrosmatic with a keen olfaction. Other possible animal
models include domesticated cattle and wild bison, since
same-sex sexual behavior has been extensively reported for
both (Jezierski, Koziorowski, Goszczyński, & Sieradzka,
1989; Lott, 1983). What about their vomero-nasal receptor
activity? Contrary to my expectation, dogs and cattle have a
markedly degenerated VNO, and most of the genes coding for
receptors in the VNO have completely degenerated and are
inactive, while their keen olfaction is due only to the primary
olfactory epithelium (Young & Trask, 2007). This evidence
from domestic mammals is, thus, consistent with the hypothesis
that a relation exists between vomero-nasal pheromone
receptor activity and same-sex sexual behavior. However,
there is evidence suggesting that in cattle the TRPC2 gene
is present and active contrary to Old World monkeys (Grus,
Shi, Zhang, & Zhang, 2005).
Research on the genes implicated in pheromone detection
and the evolution of the VNO of mammals (Moriya-Ito,
Hayakawa, Suzuki, Hagino-Yamagishi, & Nikaido, 2018)
suggests that there are a multitude of genes classified in two
super-families, which are expressed in the VNO, and some
of them in the main olfactory epithelium as well. Both the
vomero-nasal receptor genes type-1 (V1Rs) with single exon
and type-2 (V2Rs) with multiple exons are seven-transmembrane
G protein-coupled receptors (Nei, Niimura, & Nozawa,
2008). Both vomero-nasal receptor families have closely
related homologs in the vertebrate taste system: V1Rs are
closely related to T2R bitter taste receptors (Chandrashekar
et al., 2000), and V2Rs are closely related to T1R sweet and
umami taste receptors (Hoon et al., 1999).
Grus et al. (2005) found that these genes originated in
fishes, are extremely variable among mammals, and evolved
through duplication, deletion, and inactivation. Vomeronasal
receptor coding genes belong to the super-family of
genes with the highest numerical variability across species.
The proportion of intact V1Rs relates to multiple aspects of
VNO anatomy, including its relative size (Garrett & Steiper,
2014). The large variation of V1Rs in mammals may be an
adaptation to a broad range of environments, and the comparison
of V1Rs repertoires is critical for inferring the importance
of the VNO to each species (Garrett & Steiper, 2014).
Moriya-ito et al. (2018) reconstructed the phylogeny of
V1R genes in primates, almost all code for receptor proteins
that are present in the VNO. Moriya-ito et al. suggested
that, in general, V1Rs underwent positive selection, grew in
number, and are expressed in the VNO of prosimians. This
correlates with the socioecology of many prosimians, which
are nocturnal, solitary, and communicate extensively with
pheromones, including for mating (Dixson, 1995). It has been
also found that in Old and New World primates V1Rs show
a generalized trend toward degeneration (Grus et al., 2005;
Yoder & Larsen, 2014) and this regressive selection happened
not only in primates, but also in whales and bats (Grus
et al., 2005). Yoder and Larsen (2014) showed a reduction in
the number of intact V1Rs in anthropoids for which the VNO
was reduced or vestigial (Smith et al., 2002, 2011), which
suggested a correlation between the progressive inactivation
of V1Rs and reduction of the VNO. Young and Trask (2007)
also found that V2Rs families have completely degenerated in
humans, chimpanzees, macaques, cattle, and dogs. Each now
possesses 9–20 pseudogenes, but no intact V2Rs.
Rather than hypothesizing a single-gene inactivation as in
Pfau et al.’s (2019) Target Article, is it possible that general
regression of vomero-nasal functions is causally associated
with release from strict sexual response to pheromones and,
by extension, an increase in same-sex sexual behavior? It is
noteworthy that visual sexual signals, like the genital skin
swellings, are very widespread among Old World monkeys
and apes, but not in prosimians and New World monkeys
(Dixson, 1983). It has been proposed that sexual swelling
might visually signal receptivity in widely dispersed social
animals like chimpanzee, macaques, and baboons, but could
also be interpreted as evidence of the substitution of pheromone
signals with visual ones.
Now we come to my main concern with the argument forwarded
by Pfau et al. (2019): TRPC2 inactivation seems like
just one of the many genes involved in pheromone communication
in the VNO, which underwent regression partly in
New Word monkeys and completely in Old World monkeys,
as in other diurnal mammals. Why, then, suggest a specific
gene, TRPC2, as the driver of the whole behavioral transformation?
Instead, why not hypothesize that these behavioral
transformations resulted from the combined inactivation
and degeneration of a variety of genes involved in pheromone
detection and in the development and function of the
VNO. It could be argued, alternatively to Pfau et al.’s Target
Article, that the general regression of these genes allowed
the progressive shift from chemical communication toward
visual communication, including same-sex sexual behavior
as seems to have happen in New and Old World primates,
but also in sea mammals, bats, cattle, and dogs (Young &
Trask, 2007) .
The only evidence reported in Pfau et al.’s (2019) Target
Article against this more general hypothesis is that in
Gαi2 KO mice inactivation of this g-protein disrupts aggression,
but sexual behavior is not affected (Norlin, Gussing,
& Berghard, 2003). Disruption of Gαo, another g-protein
crucial for VNO function, also reduces aggression without
impacting sexual behavior (Chamero et al., 2011). Norlin
et al. (2003) reported unaltered sexual partner preference
in their Gαi2 KO mice, but Chamero et al. (2011) do not
report on any sexual behavior, so we do not know whether
any sexual changes occurred in their Gαo KO mice. Apart
from these cases, were KO mice ever produced for all other
V1Rs and V2Rs that are expressed in the VNO of mammals?
What modification in sexuality might such mice show?
Awaiting further evidence, my interpretation, at present, is
that circumstantial data best fit the more general hypothesis
for a global reduction of gene activity coding in the VNO.
We can imagine that, whenever chemical reception and communication
receded in favor of the visual communication,
selection pressures change. This might have begun when
ancestral primates invaded a diurnal niche, increased in social
complexity, developed trichromatic vision, and adopted the
use body signals (e.g., genital swelling), thereby eliciting
the evolution of sexual, rather than chemical, communication
signals (Moriya-Ito et al., 2018). Diurnal vision might
have enhanced brain size and reduced splanchno-cranial size
(Camperio Ciani, 1989), thus reinforcing reduction in VNO
size. Once sexual behavior was released from the limitation
of chemical activation, then sexuality could become much
more flexible and could be used by ancestral primates for
social communication in a variety of contexts. In extant primates,
same-sex sexual behavior might be used to modulate
aggression, reconcile conflicts, reinforce dominance rank,
and reduce social tension, thereby enriching social complexity.
The extreme example is the complex use of sexuality by
our closest relative the bonobo (Pan paniscus), in which sex
is used in the largest variety of social contexts, compared to
all other primates (Manson et al., 1997).
If my interpretation of the evidence is correct, no single
gene, such as TRPC2, but rather a whole set of genes (V1Rs,
and possibly V2Rs) lost importance. All those genes were
implicated, in one way or another, with pheromones detection
and communication in the VNO. When the VNO becomes
less important for sociosexual communication, its associated
genes become less useful and they experience more relaxed
selection pressure. The loss of selection pressure allows
for mutations to arise, such as stop codons, and generates
inactive pseudogenes (Moriya-ito et al., 2018). A relevant
exception pertains to those genes that shift function from
pheromones detection to oxygen detection. These genes are
maintained under stabilizing selective pressure, thus preserving
their functionality (Niimura, Matsui, & Touhara, 2014).
In sum, I would like to see stronger evidence that the loss of
a functional TRPC2 gene played an exclusive role in evolution
of same-sex sexuality, as opposed to a general evolutionary
transformation in mammals—not just primates—of
many vomero-nasal receptor genes, toward amplification or
degeneration.
A final critique of the Target Article, but one that is no less
relevant, is that Pfau et al.’s (2019) hypothesis does not apply
to human homosexuality. Most Old World primates have been
observed to engage in same-sex sexual behavior. Very occasionally
this involves some homosexual partner preference
(Vasey, 2002), but never exclusive homosexual orientation
as in humans. In humans, same-sex-sexual behavior lost its
social communication function almost completely to become
a sexual orientation.
I am skeptical that the olfactory and pheromonal processes
posited by Pfau et al. (2019) caused a homosexual “orientation”
in humans. The evolutionary dilemma of human
homosexual orientation has little to do with same-sex sexual
behavior, which is only one ingredient of the phenotype.
Homosexuality in humans is characterized by a novel and
specific phenotype: an individual exclusively attracted sexually
and romantically to same-sex individuals. This is the
evolutionary dilemma, exclusive same-sex sexual attraction,
which inhibits reproduction and reduces fertility. How could
such a phenotype evolve and how could it be maintained in
the population at a constant, albeit low, frequency? If this
phenotype has a genetic basis, then it should become extinct
rapidly, which we know does not happen (Camperio Ciani,
Battaglia, & Zanzotto, 2015). What are the fitness advantages
of exclusive same-sex sexual behavior in our species? Occasional
same-sex sexual behavior does not exclude heterosexual
sex and reproduction. On the contrary, it might provide a
selective benefit to individuals, in reducing aggressiveness
by using sexual pleasure to facilitate appeasement, but even if
this is true, it is generally not the case in humans. In animals,
same-sex sexual behavior enriches communication, sociality,
and ultimately benefits individuals, so there is no evolutionary
dilemma here. This is the ultimate reason that same-sex
sexual behavior evolved in many social organisms (Bagemihl,
1999). That said, these social uses of same-sex sexual behavior
do not produce exclusive homosexuality.
Pfau et al., in the Target Article, contend that the absence
of reports on possible homosexual orientation in primates,
including bonobos, might be ascribed to the possibility that
researchers not have detected it yet. They suggest that the
absence of evidence is not evidence of absence, but in this
case, it is improbable. Vasey (2002) reported facultative
(i.e., nonexclusive) homosexual preference for a few animals,
including the domestic rams and few other ungulates,
as well as female Japanese macaque (Macaca fuscata). These
females occasionally show a preference for same-sex sexual
partners over opposite-sex alternatives, but nevertheless they
mate heterosexually and they all reproduce, according to my
direct experience (Camperio Ciani, 1997; Corradino, 1990).
Moreover, most primatologist will acknowledge that primates
are difficult to locate in the wild, especially forest dwelling
ones; however, once located, sexual behavior becomes overt
(both visually and vocally) and very conspicuous in most
species, if not all. Sexual interactions in wild primates are
much easier to observe than in our species. Infinite hours of
observation, including in the wild, focusing on sexual behavior
in males and females have been undertaken by ethologists.
With such a large sample, it would have been easy to
locate individuals that engage in exclusive same-sex sexual
behavior, but no one has. I have been observing several species
of macaques in North Africa and South-East Asia and
commonly observe same-sex behavior among both females
and males, but never once have I observed a single-subject
mating exclusively with same-sex partners (Camperio Ciani
1986; Camperio Ciani, Mouna, & Arhou, 2000; Camperio
Ciani et al., 2005). There is only one species in which some
males exhibit a homosexual orientation, but this is in sheep,
not in primates, and is restricted to domesticated, that have
been artificially selected. Domestic rams can thus furnish
information on the neurophysiology and endocrinology of
homosexuality, but they cannot furnish information about
how natural selection might have produced such a phenotype
(Roselli, Larkin, Schrunk, & Stormshak, 2004).
Pfau et al. (2019) suggested that if homosexual individuals
occur in small groups, as might be the case for many
primates, there might be no possibility of finding a homosexual
partner with the same orientation. This, they suggest,
might help account for the lack of observations of exclusive
same-sex sexual partner preference in primates. This speculation
is untenable. First, many primates, including baboons,
macaques, and vervets, live in large multi-male multi-female
groups. If occasional same-sex behavior is already present
within a species—as is the case for many primates—an exclusively
homosexual individual, should one exist, could find
several same-sex partners with whom they could engage in
sex, even if those partners were not exclusively homosexual
themselves. This in fact happens also in our own species,
where exclusive homosexual individuals can find occasional
partners who are heterosexual (Whitam, 1992).
In conclusion, the hypothesis that the decline of pheromonal
communication allowed for the evolution of social
complexity, including same-sex sexuality, is compelling. In
my view, the idea that a single gene, and not a whole set of
genes, promoted this shift needs further testing. Regardless,
Pfau et al.’s (2019) hypothesis while heuristic for the evolution
of same-sex sexuality in nonhuman primates, fall short
of explaining the evolution of an exclusively homosexual
phenotype as seen in humans.
A variety of mammals, including primates, communicate
through pheromones, which are volatile chemical signals
produced by glands and detected through the vomero-nasal
organ (VNO). This manner of communication is effective
and fundamental for eliciting innate responses to locate
sexual partners and inducing sexual behavior. Pfau, Jordan,
and Breedlove, (2019) hypothesized that progressive
degeneration of a single-gene coding for pheromones receptors
in the VNO of mammals may have triggered a cascade
of functional and behavioral consequences that facilitated
the development of new modes of sexual communication,
including same-sex sexual behavior in primates and humans.
This hypothesis is compelling, testable, and heuristic.
In their Target Article, Pfau et al. (2019) suggest that, during
primate evolution, inactivation of the transient receptor
potential cation channel 2 (TRPC2) gene caused a shift from
strictly pheromonal-driven sexual behavior toward a more
flexible sexual response that allowed for occasional samesex
sexual behavior. In other words, a more flexible sexual
response to different and varied stimuli might have allowed
the use of sex, including same-sex sexual activity, in both
sexes, in contexts beyond reproduction such as dominance
displays, reconciliation, and appeasement (de Waal, 1989).
The main evidence in support of Pfau et al.’s (2019)
hypothesis comes from knock-out (KO) TRPC2 mice. Pfau
et al. found that this experimental strain of KO mice exhibits
delay development and altered intraspecific interactions such
as sex discrimination and male–male aggression (Leypold
et al., 2002; Stowers, Holy, Meister, Dulac, & Koentges,
2002). Most importantly, compared to wild mice strains,
adult male and female KO TRPC2 mice were observed to
engage in unprecedented levels of same-sex sexual behavior
including mounting and pelvic thrusting.
Comparing KO TRPC2 mice and Old World monkeys,
Pfau et al. (2019) furnish evidence that catarrhine primates,
which lack a VNO, also have a nonfunctional TRPC2 gene.
They argued that like KO TRPC2 mice, catarrhine primates
exhibit reduced aggressions and delayed development. Based
on these comparisons, they proposed that this TRPC2 single-
gene inactivation might explain not only the cause of
same-sex sexual behavior in nonhuman primates, but also the
cause of sexual orientation in humans. Further, they proposed
that the inactivation of the TRPC2 gene promoted a series
of behavioral and social transformation that are common in
domesticated animals and self-domesticated humans (Hare,
2017; Hare, Wobber, & Wrangham, 2012).
The primate data do not fit Pfau et al’s (2019) hypothesis
perfectly, however, and as the authors admit, there are some
prosimians (e.g., brown lemurs, Lemur fulvus, and sifakas,
Propitecus verreuxi; Bagemihl, 1999), as well as some New
World monkeys (e.g., common marmoset, Callitrix jacchus,
and Geoffroy’s tamarin, Saguinus geoffroyi) that have intact
TRPC2 genes and show same-sex sexual behavior (e.g.,
Manson, Perry, & Parish, 1997; Rothe, 1975). Conversely,
there are a number of Old World monkeys such as gibbons
and olive colobus (Procolobus verus) that lack a functional
TRPC2 gene, but have never been shown, in field observations,
to exhibit same-sex sexual behavior in either sexes.
However, these are minor exceptions, and in general Pfau
et al.’s hypothesis is supported by the primate data.
Pfau et al.’s (2019) hypothesis could also be tested in
other mammals known to have same-sex sexual behavior.
For example, dogs (Canis spp.) are known to have same-sex
sexual behavior both in females (Beach, Rogers, & LeBoeuf,
1968) and in males (Dagg, 1984), and at the same time they
are macrosmatic with a keen olfaction. Other possible animal
models include domesticated cattle and wild bison, since
same-sex sexual behavior has been extensively reported for
both (Jezierski, Koziorowski, Goszczyński, & Sieradzka,
1989; Lott, 1983). What about their vomero-nasal receptor
activity? Contrary to my expectation, dogs and cattle have a
markedly degenerated VNO, and most of the genes coding for
receptors in the VNO have completely degenerated and are
inactive, while their keen olfaction is due only to the primary
olfactory epithelium (Young & Trask, 2007). This evidence
from domestic mammals is, thus, consistent with the hypothesis
that a relation exists between vomero-nasal pheromone
receptor activity and same-sex sexual behavior. However,
there is evidence suggesting that in cattle the TRPC2 gene
is present and active contrary to Old World monkeys (Grus,
Shi, Zhang, & Zhang, 2005).
Research on the genes implicated in pheromone detection
and the evolution of the VNO of mammals (Moriya-Ito,
Hayakawa, Suzuki, Hagino-Yamagishi, & Nikaido, 2018)
suggests that there are a multitude of genes classified in two
super-families, which are expressed in the VNO, and some
of them in the main olfactory epithelium as well. Both the
vomero-nasal receptor genes type-1 (V1Rs) with single exon
and type-2 (V2Rs) with multiple exons are seven-transmembrane
G protein-coupled receptors (Nei, Niimura, & Nozawa,
2008). Both vomero-nasal receptor families have closely
related homologs in the vertebrate taste system: V1Rs are
closely related to T2R bitter taste receptors (Chandrashekar
et al., 2000), and V2Rs are closely related to T1R sweet and
umami taste receptors (Hoon et al., 1999).
Grus et al. (2005) found that these genes originated in
fishes, are extremely variable among mammals, and evolved
through duplication, deletion, and inactivation. Vomeronasal
receptor coding genes belong to the super-family of
genes with the highest numerical variability across species.
The proportion of intact V1Rs relates to multiple aspects of
VNO anatomy, including its relative size (Garrett & Steiper,
2014). The large variation of V1Rs in mammals may be an
adaptation to a broad range of environments, and the comparison
of V1Rs repertoires is critical for inferring the importance
of the VNO to each species (Garrett & Steiper, 2014).
Moriya-ito et al. (2018) reconstructed the phylogeny of
V1R genes in primates, almost all code for receptor proteins
that are present in the VNO. Moriya-ito et al. suggested
that, in general, V1Rs underwent positive selection, grew in
number, and are expressed in the VNO of prosimians. This
correlates with the socioecology of many prosimians, which
are nocturnal, solitary, and communicate extensively with
pheromones, including for mating (Dixson, 1995). It has been
also found that in Old and New World primates V1Rs show
a generalized trend toward degeneration (Grus et al., 2005;
Yoder & Larsen, 2014) and this regressive selection happened
not only in primates, but also in whales and bats (Grus
et al., 2005). Yoder and Larsen (2014) showed a reduction in
the number of intact V1Rs in anthropoids for which the VNO
was reduced or vestigial (Smith et al., 2002, 2011), which
suggested a correlation between the progressive inactivation
of V1Rs and reduction of the VNO. Young and Trask (2007)
also found that V2Rs families have completely degenerated in
humans, chimpanzees, macaques, cattle, and dogs. Each now
possesses 9–20 pseudogenes, but no intact V2Rs.
Rather than hypothesizing a single-gene inactivation as in
Pfau et al.’s (2019) Target Article, is it possible that general
regression of vomero-nasal functions is causally associated
with release from strict sexual response to pheromones and,
by extension, an increase in same-sex sexual behavior? It is
noteworthy that visual sexual signals, like the genital skin
swellings, are very widespread among Old World monkeys
and apes, but not in prosimians and New World monkeys
(Dixson, 1983). It has been proposed that sexual swelling
might visually signal receptivity in widely dispersed social
animals like chimpanzee, macaques, and baboons, but could
also be interpreted as evidence of the substitution of pheromone
signals with visual ones.
Now we come to my main concern with the argument forwarded
by Pfau et al. (2019): TRPC2 inactivation seems like
just one of the many genes involved in pheromone communication
in the VNO, which underwent regression partly in
New Word monkeys and completely in Old World monkeys,
as in other diurnal mammals. Why, then, suggest a specific
gene, TRPC2, as the driver of the whole behavioral transformation?
Instead, why not hypothesize that these behavioral
transformations resulted from the combined inactivation
and degeneration of a variety of genes involved in pheromone
detection and in the development and function of the
VNO. It could be argued, alternatively to Pfau et al.’s Target
Article, that the general regression of these genes allowed
the progressive shift from chemical communication toward
visual communication, including same-sex sexual behavior
as seems to have happen in New and Old World primates,
but also in sea mammals, bats, cattle, and dogs (Young &
Trask, 2007) .
The only evidence reported in Pfau et al.’s (2019) Target
Article against this more general hypothesis is that in
Gαi2 KO mice inactivation of this g-protein disrupts aggression,
but sexual behavior is not affected (Norlin, Gussing,
& Berghard, 2003). Disruption of Gαo, another g-protein
crucial for VNO function, also reduces aggression without
impacting sexual behavior (Chamero et al., 2011). Norlin
et al. (2003) reported unaltered sexual partner preference
in their Gαi2 KO mice, but Chamero et al. (2011) do not
report on any sexual behavior, so we do not know whether
any sexual changes occurred in their Gαo KO mice. Apart
from these cases, were KO mice ever produced for all other
V1Rs and V2Rs that are expressed in the VNO of mammals?
What modification in sexuality might such mice show?
Awaiting further evidence, my interpretation, at present, is
that circumstantial data best fit the more general hypothesis
for a global reduction of gene activity coding in the VNO.
We can imagine that, whenever chemical reception and communication
receded in favor of the visual communication,
selection pressures change. This might have begun when
ancestral primates invaded a diurnal niche, increased in social
complexity, developed trichromatic vision, and adopted the
use body signals (e.g., genital swelling), thereby eliciting
the evolution of sexual, rather than chemical, communication
signals (Moriya-Ito et al., 2018). Diurnal vision might
have enhanced brain size and reduced splanchno-cranial size
(Camperio Ciani, 1989), thus reinforcing reduction in VNO
size. Once sexual behavior was released from the limitation
of chemical activation, then sexuality could become much
more flexible and could be used by ancestral primates for
social communication in a variety of contexts. In extant primates,
same-sex sexual behavior might be used to modulate
aggression, reconcile conflicts, reinforce dominance rank,
and reduce social tension, thereby enriching social complexity.
The extreme example is the complex use of sexuality by
our closest relative the bonobo (Pan paniscus), in which sex
is used in the largest variety of social contexts, compared to
all other primates (Manson et al., 1997).
If my interpretation of the evidence is correct, no single
gene, such as TRPC2, but rather a whole set of genes (V1Rs,
and possibly V2Rs) lost importance. All those genes were
implicated, in one way or another, with pheromones detection
and communication in the VNO. When the VNO becomes
less important for sociosexual communication, its associated
genes become less useful and they experience more relaxed
selection pressure. The loss of selection pressure allows
for mutations to arise, such as stop codons, and generates
inactive pseudogenes (Moriya-ito et al., 2018). A relevant
exception pertains to those genes that shift function from
pheromones detection to oxygen detection. These genes are
maintained under stabilizing selective pressure, thus preserving
their functionality (Niimura, Matsui, & Touhara, 2014).
In sum, I would like to see stronger evidence that the loss of
a functional TRPC2 gene played an exclusive role in evolution
of same-sex sexuality, as opposed to a general evolutionary
transformation in mammals—not just primates—of
many vomero-nasal receptor genes, toward amplification or
degeneration.
A final critique of the Target Article, but one that is no less
relevant, is that Pfau et al.’s (2019) hypothesis does not apply
to human homosexuality. Most Old World primates have been
observed to engage in same-sex sexual behavior. Very occasionally
this involves some homosexual partner preference
(Vasey, 2002), but never exclusive homosexual orientation
as in humans. In humans, same-sex-sexual behavior lost its
social communication function almost completely to become
a sexual orientation.
I am skeptical that the olfactory and pheromonal processes
posited by Pfau et al. (2019) caused a homosexual “orientation”
in humans. The evolutionary dilemma of human
homosexual orientation has little to do with same-sex sexual
behavior, which is only one ingredient of the phenotype.
Homosexuality in humans is characterized by a novel and
specific phenotype: an individual exclusively attracted sexually
and romantically to same-sex individuals. This is the
evolutionary dilemma, exclusive same-sex sexual attraction,
which inhibits reproduction and reduces fertility. How could
such a phenotype evolve and how could it be maintained in
the population at a constant, albeit low, frequency? If this
phenotype has a genetic basis, then it should become extinct
rapidly, which we know does not happen (Camperio Ciani,
Battaglia, & Zanzotto, 2015). What are the fitness advantages
of exclusive same-sex sexual behavior in our species? Occasional
same-sex sexual behavior does not exclude heterosexual
sex and reproduction. On the contrary, it might provide a
selective benefit to individuals, in reducing aggressiveness
by using sexual pleasure to facilitate appeasement, but even if
this is true, it is generally not the case in humans. In animals,
same-sex sexual behavior enriches communication, sociality,
and ultimately benefits individuals, so there is no evolutionary
dilemma here. This is the ultimate reason that same-sex
sexual behavior evolved in many social organisms (Bagemihl,
1999). That said, these social uses of same-sex sexual behavior
do not produce exclusive homosexuality.
Pfau et al., in the Target Article, contend that the absence
of reports on possible homosexual orientation in primates,
including bonobos, might be ascribed to the possibility that
researchers not have detected it yet. They suggest that the
absence of evidence is not evidence of absence, but in this
case, it is improbable. Vasey (2002) reported facultative
(i.e., nonexclusive) homosexual preference for a few animals,
including the domestic rams and few other ungulates,
as well as female Japanese macaque (Macaca fuscata). These
females occasionally show a preference for same-sex sexual
partners over opposite-sex alternatives, but nevertheless they
mate heterosexually and they all reproduce, according to my
direct experience (Camperio Ciani, 1997; Corradino, 1990).
Moreover, most primatologist will acknowledge that primates
are difficult to locate in the wild, especially forest dwelling
ones; however, once located, sexual behavior becomes overt
(both visually and vocally) and very conspicuous in most
species, if not all. Sexual interactions in wild primates are
much easier to observe than in our species. Infinite hours of
observation, including in the wild, focusing on sexual behavior
in males and females have been undertaken by ethologists.
With such a large sample, it would have been easy to
locate individuals that engage in exclusive same-sex sexual
behavior, but no one has. I have been observing several species
of macaques in North Africa and South-East Asia and
commonly observe same-sex behavior among both females
and males, but never once have I observed a single-subject
mating exclusively with same-sex partners (Camperio Ciani
1986; Camperio Ciani, Mouna, & Arhou, 2000; Camperio
Ciani et al., 2005). There is only one species in which some
males exhibit a homosexual orientation, but this is in sheep,
not in primates, and is restricted to domesticated, that have
been artificially selected. Domestic rams can thus furnish
information on the neurophysiology and endocrinology of
homosexuality, but they cannot furnish information about
how natural selection might have produced such a phenotype
(Roselli, Larkin, Schrunk, & Stormshak, 2004).
Pfau et al. (2019) suggested that if homosexual individuals
occur in small groups, as might be the case for many
primates, there might be no possibility of finding a homosexual
partner with the same orientation. This, they suggest,
might help account for the lack of observations of exclusive
same-sex sexual partner preference in primates. This speculation
is untenable. First, many primates, including baboons,
macaques, and vervets, live in large multi-male multi-female
groups. If occasional same-sex behavior is already present
within a species—as is the case for many primates—an exclusively
homosexual individual, should one exist, could find
several same-sex partners with whom they could engage in
sex, even if those partners were not exclusively homosexual
themselves. This in fact happens also in our own species,
where exclusive homosexual individuals can find occasional
partners who are heterosexual (Whitam, 1992).
In conclusion, the hypothesis that the decline of pheromonal
communication allowed for the evolution of social
complexity, including same-sex sexuality, is compelling. In
my view, the idea that a single gene, and not a whole set of
genes, promoted this shift needs further testing. Regardless,
Pfau et al.’s (2019) hypothesis while heuristic for the evolution
of same-sex sexuality in nonhuman primates, fall short
of explaining the evolution of an exclusively homosexual
phenotype as seen in humans.
Trump Depression: Liberals report being more depressed when asked directly about the effects of the 2016 election; however, more indirect measures show a short-lived or non-existent effect
Simchon, Almog, Sharath Guntuku, Rotem Simhon, Lyle H. Ungar, Ran Hassin, and michael gilead. 2020. “Political Depression? A Big-data, Multi-method Investigation of Americans’ Emotional Response to the Trump Presidency.” PsyArXiv. April 21. doi:10.1037/xge0000767
Abstract: Can a political loss in a participatory democracy lead to psychopathology? While some studies provide support for pathological levels of election-related distress in Liberal Americans, it has also been suggested that the public and professional discourse has increasingly over-generalized concepts of trauma and psychopathology. Here, we examine this debate in the context of the 2016 US presidential election, and investigate whether Liberal (vs. Conservative) Americans exhibited increased levels of depression in response to the Trump presidency. We observe that Liberals report being more depressed when asked directly about the effects of the election; however, more indirect measures show a short-lived or non-existent effect. We examined self-report measures of clinical depression with and without a reference to the election (Studies 1A & 1B), analyzed Twitter discourse and measured users’ levels of depression using a machine-learning-based model (Study 2), conducted time-series analysis of depression-related search behavior on Google (Study 3), examined the proportion of antidepressants consumption in Medicaid (Study 4), and analyzed daily survey data of hundreds of thousands of Americans (Study 5)—and saw that at the aggregate level, empirical data reject the accounts of “Trump Depression”. We discuss possible interpretations for the discrepancies between the direct and indirect measures. The current investigation demonstrates how big-data sources can provide an unprecedented view of the psychological consequences of political events, and sheds light on the complex relation between the political and the personal spheres.
Abstract: Can a political loss in a participatory democracy lead to psychopathology? While some studies provide support for pathological levels of election-related distress in Liberal Americans, it has also been suggested that the public and professional discourse has increasingly over-generalized concepts of trauma and psychopathology. Here, we examine this debate in the context of the 2016 US presidential election, and investigate whether Liberal (vs. Conservative) Americans exhibited increased levels of depression in response to the Trump presidency. We observe that Liberals report being more depressed when asked directly about the effects of the election; however, more indirect measures show a short-lived or non-existent effect. We examined self-report measures of clinical depression with and without a reference to the election (Studies 1A & 1B), analyzed Twitter discourse and measured users’ levels of depression using a machine-learning-based model (Study 2), conducted time-series analysis of depression-related search behavior on Google (Study 3), examined the proportion of antidepressants consumption in Medicaid (Study 4), and analyzed daily survey data of hundreds of thousands of Americans (Study 5)—and saw that at the aggregate level, empirical data reject the accounts of “Trump Depression”. We discuss possible interpretations for the discrepancies between the direct and indirect measures. The current investigation demonstrates how big-data sources can provide an unprecedented view of the psychological consequences of political events, and sheds light on the complex relation between the political and the personal spheres.
Exposure to research on the genetic and biological etiology of political attitudes influences warmth toward partisan outgroups and preferences over political compromise
Severson, Alexander. 2020. “Homo Politicus Was Born This Way: How Understanding the Biology of Political Belief Promotes Depolarization.” SocArXiv. April 25. doi:10.31235/osf.io/7qgcr
Abstract: Most individuals perceive ideological beliefs as being freely chosen. Recent research in genopolitics and neuroscience, however, suggests that this conviction is partially unwarranted given that biological and genetic factors explain more variance in political attitudes than choice and environmental factors. Thus, it is worth exploring whether exposure to this research on the biological and genetic basis of political attitudes might influence levels of affective polarization because such exposure might reduce the perceived moral culpability of partisan outgroups for the endorsement of oppositional beliefs. In this paper, I employ an online survey experiment on Amazon Mechanical Turk (N = 487) to assess whether exposure to research on the genetic and biological etiology of political attitudes influences warmth toward partisan outgroups and preferences over political compromise. I present evidence that nontrivial numbers of participants in the treatment group reject the underlying science and do not update their genetic trait attributions for political attitudes. However, I also find that when the treatment is successful at increasing biological and genetic trait attributions, exposure to this research depolarizes strong-identifying partisans. Moreover, as partisans increasingly endorse biological and genetic trait attributions for political attitudes, they increasingly hold favorable attitudes toward political outgroups. These patterns suggest a potentially profitable inroad for political polarization interventions going forward.
Abstract: Most individuals perceive ideological beliefs as being freely chosen. Recent research in genopolitics and neuroscience, however, suggests that this conviction is partially unwarranted given that biological and genetic factors explain more variance in political attitudes than choice and environmental factors. Thus, it is worth exploring whether exposure to this research on the biological and genetic basis of political attitudes might influence levels of affective polarization because such exposure might reduce the perceived moral culpability of partisan outgroups for the endorsement of oppositional beliefs. In this paper, I employ an online survey experiment on Amazon Mechanical Turk (N = 487) to assess whether exposure to research on the genetic and biological etiology of political attitudes influences warmth toward partisan outgroups and preferences over political compromise. I present evidence that nontrivial numbers of participants in the treatment group reject the underlying science and do not update their genetic trait attributions for political attitudes. However, I also find that when the treatment is successful at increasing biological and genetic trait attributions, exposure to this research depolarizes strong-identifying partisans. Moreover, as partisans increasingly endorse biological and genetic trait attributions for political attitudes, they increasingly hold favorable attitudes toward political outgroups. These patterns suggest a potentially profitable inroad for political polarization interventions going forward.
People who are intellectually humble display less hostility towards conflicting viewpoints, which should induce less polarization, but can polarize strongly against what is perceived as arrogant, close minded individuals
Nadelhoffer, Thomas, Gus Skorburg, Rose Graves, Mark R. Leary, and Walter Sinnott-Armstrong. 2020. “Partisanship, Humility, and Polarization.” OSF Preprints. April 19. doi:10.31219/osf.io/e8yj6
Abstract: Much of the literature from political psychology has focused on the negative traits that are positively associated with affective polarization—e.g., animus, arrogance, distrust, hostility, and outrage. Not as much attention has been focused on the positive traits that might be negatively associated with polarization. For instance, given that people who are intellectually humble display greater openness and less hostility towards conflicting viewpoints (Krumrei-Mancuso & Rouse, 2016; Hopkin et al., 2014; Porter & Schumann, 2018), one might reasonably expect them to be less polarized. We ran two studies designed to explore the relationship between various forms of humility and polarization. Our chief finding is that people who value humility are prone to what we are calling epistemic polarization—that is, judging the epistemic traits of contrapartisans negatively—which in turn plays a role in polarization more generally. Not only are contrapartisans deemed to have the wrong moral and political beliefs, they are also viewed as less humble and more arrogant, close-minded, and irrational. This makes matters even worse when it comes to the growing partisan divide. In light of our findings, we believe that the novel concept of epistemic polarization that we introduce is a promising target for further investigation.
Abstract: Much of the literature from political psychology has focused on the negative traits that are positively associated with affective polarization—e.g., animus, arrogance, distrust, hostility, and outrage. Not as much attention has been focused on the positive traits that might be negatively associated with polarization. For instance, given that people who are intellectually humble display greater openness and less hostility towards conflicting viewpoints (Krumrei-Mancuso & Rouse, 2016; Hopkin et al., 2014; Porter & Schumann, 2018), one might reasonably expect them to be less polarized. We ran two studies designed to explore the relationship between various forms of humility and polarization. Our chief finding is that people who value humility are prone to what we are calling epistemic polarization—that is, judging the epistemic traits of contrapartisans negatively—which in turn plays a role in polarization more generally. Not only are contrapartisans deemed to have the wrong moral and political beliefs, they are also viewed as less humble and more arrogant, close-minded, and irrational. This makes matters even worse when it comes to the growing partisan divide. In light of our findings, we believe that the novel concept of epistemic polarization that we introduce is a promising target for further investigation.
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