Physical Strength Partly Explains Sex Differences in Trait Anxiety in Young Americans

Physical Strength Partly Explains Sex Differences in Trait Anxiety in Young Americans. Nicholas Kerry, Damian R. Murray. Psychological Science, April 2, 2021. https://doi.org/10.1177/0956797620971298

Abstract: Among the most consistent sex differences to emerge from personality research is that women score higher than men on the Big Five personality trait Neuroticism. However, there are few functionally coherent explanations for this sex difference. The current studies tested whether this sex difference is due, in part, to variation in physical capital. Two preregistered studies (total N = 878 U.S. students) found that sex differences in the anxiety facet of Neuroticism were mediated by variation in physical strength and self-perceived formidability. Study 1 (N = 374) did not find a predicted mediation effect for overall Neuroticism but found a mediation effect for anxiety (the facet of Neuroticism most strongly associated with grip strength). Study 2 (N = 504) predicted and replicated this mediation effect. Further, sex differences in anxiety were serially mediated by grip strength and self-perceived formidability. These findings add to a nascent literature suggesting that differences in physical attributes may partially explain sex differences in personality.

Keywords: anxiety, Neuroticism, personality, sex differences, physical strength, formidability, open data, open materials, preregistered

General Discussion

In two studies, grip strength negatively predicted anxiety, and sex differences in anxiety were serially mediated by grip strength and self-perceived formidability. These findings suggest that some sex-based variation in personality may be partly attributable to variation in physical attributes.

These results suggest the testable hypothesis that other psychological and behavioral sex differences could be partly explained by differences in physical attributes. For example, there is evidence that social dominance and aggression—both of which tend to be higher in men—also covary intrasexually with physical strength (Farrington, 1989; Gallup et al., 2007; Price et al., 2011). Future research might investigate whether these and other psychological sex differences can be partly explained by differences in strength or stature.

Important limitations of this work should be noted. First, within-sex associations between strength and anxiety were small and somewhat inconsistent, and sex still accounted for some variance in anxiety beyond that explained by physical strength. Imperfect measurement of the key variables may have contributed to the small effects observed (see the Supplemental Material). Another possible explanation for the small within-sex effects is that the measures of strength and formidability employed here acted as a proxy for another variable, such as health or attractiveness (which both covary with grip strength; see Gallup & Fink, 2018). Although we cannot rule out this explanation, analyses reported in the Supplemental Material found relationships to be robust when controlling for several potential confounds, including body mass index, age, and a measure of self-perceived attractiveness. Similarly, though, these effects could be explained by a common underlying physiological factor, such as developmental testosterone levels (testosterone levels correlate negatively with anxiety in both sexes; see McHenry et al., 2014). Finally, a key limitation relating to the causal interpretation of these findings is that the mediational models presented here use cross-sectional data and cannot alone demonstrate causality. Thus, although the data here are consistent with the hypothesis that lower physical strength leads to higher anxiety, we cannot rule out alternative causal explanations.

Further, several additional questions remain unanswered. Is the association between strength and anxiety best explained by developmental calibration (i.e., people adapting behaviors to their strengths and weaknesses), genetic pleiotropy (i.e., genes associated with physical formidability also being associated with lower dispositional anxiety; see Lukaszewski & Roney, 2011), or facultative epigenetic processes whereby methylation of genes associated with strength also has consequences for anxiety? And, importantly, will these relationships generalize to other cultures, and would effects be larger for cultures and populations in which formidability is a more functional part of social life? Although these and other questions must be addressed in future research, the studies presented here support the hypothesis that sex differences in anxiety can be partly explained by differences in physical strength and self-perceived formidability. These findings suggest that further work on sex differences in personality may benefit from an increased focus on the role of physical attributes.

Some navigation abilities decline in midlife and differ by sex, but others (path integration) do not decline

Age-Related Changes in Spatial Navigation Are Evident by Midlife and Differ by Sex. Shuying Yu et al. Psychological Science, April 5, 2021. https://doi.org/10.1177/0956797620979185

Abstract: Accumulating evidence suggests that distinct aspects of successful navigation—path integration, spatial-knowledge acquisition, and navigation strategies—change with advanced age. Yet few studies have established whether navigation deficits emerge early in the aging process (prior to age 65) or whether early age-related deficits vary by sex. Here, we probed healthy young adults (ages 18–28) and midlife adults (ages 43–61) on three essential aspects of navigation. We found, first, that path-integration ability shows negligible effects of sex or age. Second, robust sex differences in spatial-knowledge acquisition are observed not only in young adulthood but also, although with diminished effect, at midlife. Third, by midlife, men and women show decreased ability to acquire spatial knowledge and increased reliance on taking habitual paths. Together, our findings indicate that age-related changes in navigation ability and strategy are evident as early as midlife and that path-integration ability is spared, to some extent, in the transition from youth to middle age.

Keywords: cognitive aging, virtual reality, path integration, wayfinding

Check also Gender differences in spatial navigation: Characterizing wayfinding behaviors. Ascher K. Munion et al. Psychonomic Bulletin & Review, August 20 2019. https://www.bipartisanalliance.com/2019/08/gender-differences-in-spatial.html

And: A meta-analysis of sex differences in human navigation skills. Alina Nazareth et al. Psychonomic Bulletin & Review, July 3 2019. https://www.bipartisanalliance.com/2019/07/a-meta-analysis-of-sex-differences-in.html

Discussion

The present study tested the effects of age and sex on three core aspects of spatial navigation in young and midlife adults: path integration, spatial-knowledge acquisition, and navigational strategy. Building on previous chronological-aging studies (Driscoll et al., 2005; Zhong & Moffat, 2016), we found that some age-related differences in spatial navigation are evident by midlife. Although path-integration ability was largely preserved with age in the loop-closure task, pronounced age-related differences were observed in the ability to acquire spatial knowledge in the maze-learning task and in the selection of a navigational strategy in the dual-solution paradigm. No major sex difference was observed for path integration, but sex differences were found for acquiring spatial knowledge and navigation strategy. Overall, sex differences present in young adults tended to be reduced with age.

Previous findings indicate poor path integration in adults 65 years or older (Adamo et al., 2012; Coughlan, Coutrot, et al., 2018; Harris & Wolbers, 2012), but we saw no such change in midlife adults, suggesting that age-related changes arise later in the aging process. In previous studies, older adults had access to a single cue (vision or proprioception), whereas our task provided participants with multiple cues. Future studies should examine whether reduced performance is evident in midlife when performance is constrained to a single cue. Although there was a sex difference in degrees traveled, with women tending to overshoot and men tending to undershoot, this difference did not affect the overall position error. The tendency to overshoot could be a cautionary measure by women to ensure they reach the start (e.g., Gagnon et al., 2016). In sum, we found little evidence for sex or aging effects in path integration.

Sex differences were evident in measures of spatial-knowledge acquisition from both unrestricted free exploration (maze-learning task) and route-based learning (dual-solution paradigm). In the maze-learning task, midlife adults did not explore as much as younger adults. After accounting for differing numbers of exploration moves, we found that sex differences remained robust in young adults and diminished in midlife adults. Floor effects were present in the maze-learning task for midlife adults, making sex differences less detectible. It is possible that age-related changes in the brain hinder the ability for midlife adults to create a comprehensive cognitive map, which in turn makes sex differences in performance harder to detect. In the dual-solution paradigm, wayfinding success indicates how well participants learned the environment from a route. Despite equal exposure to the route, midlife adults were less successful than younger adults, consistent with previous studies on learning from routes (Harris & Wolbers, 2014; Wiener et al., 2013; Zhong & Moffat, 2016). Together, these findings suggest that spatial learning is impaired as early as midlife. These data are consistent with findings from an earlier study demonstrating age-related performance decrements in a virtual Morris water-maze task by midlife (Driscoll et al., 2005).

Navigation strategies in the dual-solution paradigm indicated that young men took more shortcuts than young women, a finding that echoes previous results by Boone et al. (2018, 2019). Our study provides the first evidence that age-related differences in navigation strategies are evident by midlife, with midlife adults using fewer shortcuts than younger adults. This result is consistent with reports that older adults use more habitual routes when navigating (Harris et al., 2012; Lester et al., 2017; Wiener et al., 2013) and suggests that strategies have already shifted by midlife. In addition, we found that the sex difference observed in young adults did not persist in midlife adults. Further, the heat maps indicated that although young men were more likely to take shortcuts through the middle of the maze, all other groups relied on the learned route to navigate within the maze. Thus, the major change with age was a reduction of place-based strategies in men.

Several limitations should be considered when interpreting these findings. First, it is possible that older adults have less experience with using computer gaming controls (such as those used in the dual-solution paradigm) compared with younger adults, and this could contribute to navigation inefficiency in the desktop virtual environments. However, age-related differences also existed for the maze-learning task, which requires the use of only a single button press at each intersection. This indicates that poorer performance for midlife adults is unlikely to be due to computer experience alone and is likely to be related to age-related changes in participants’ brains that deterred successful acquisition of spatial information from the environment. A direct assessment of participants’ gaming experience and experience in virtual environments was not acquired, so this issue cannot be fully resolved.

Second, the midlife period is characterized by significant neuroendocrine changes in women. Our sample included midlife women, spanning the spectrum from late premenopausal to early postmenopausal. Although the study was not powered to assess performance by reproductive stage or endocrine status in the current sample, this will be a major focus of our future research. Further, young adult women were tested independently of menstrual-cycle stage. Given accumulating evidence that menstrual-cycle stage and sex-hormone concentrations impact spatial cognition (Courvoisier et al., 2013; Hussain et al., 2016) and aspects of navigation (Korol et al., 2004), future studies should clarify the extent to which these relationships hold across measures of path integration, wayfinding, and navigation strategy.

Finally, the largest age effects were observed in men, with a steep decline in wayfinding success (maze-learning task) and a shift toward taking habitual routes (dual-solution paradigm). It is possible that these unexpected effects have a neuroendocrine basis. Testosterone production in men begins to diminish when they are in their early 30s and gradually declines throughout the adult life span (Feldman et al., 2002). Testosterone loss influences cognitive and brain function in aging men, including visual and verbal memory and spatial cognition (Moffat, 2005). Driscoll and colleagues (2005) found that the male spatial advantage in a virtual Morris water-maze task is related to circulating testosterone. Thus, the role of testosterone should be considered as a factor in future studies of navigation and aging.

In sum, we examined signatures of early aging in three navigational tasks, opening up new avenues for understanding healthy aging. The differing patterns of age and sex across our three navigational tasks suggest that different aspects of navigation could tap into separate brain systems. Although path integration has typically been used as an early marker for dementia (Coughlan, Laczó, et al., 2018; Kunz et al., 2015), our findings suggest that spatial-knowledge acquisition and strategy use are more sensitive to the earliest stages of the aging process. Understanding the trajectories of healthy aging—and how they differ for men and women—will help pave the way for developing behavioral and neural markers for dementia.

Incidence of suicide decreased among Swedish men aged 50–59 after July 2013 when patent rights to sildenafil (i.e., Viagra) ceased, prices fell, and its use increased dramatically

Sildenafil and suicide in Sweden. Ralph Catalano, Sidra Goldman-Mellor, Tim A. Bruckner & Terry Hartig. European Journal of Epidemiology, Apr 1 2021. https://link.springer.com/article/10.1007/s10654-021-00738-4

Abstract: Much theory asserts that sexual intimacy sustains mental health. Experimental tests of such theory remain rare and have not provided compelling evidence because ethical, practical, and cultural constraints bias samples and results. An epidemiologic approach would, therefore, seem indicated given the rigor the discipline brings to quasi-experimental research. For reasons that remain unclear, however, epidemiologist have largely ignored such theory despite the plausibility of the processes implicated, which engender, for example, happiness, feelings of belonging and self-worth, and protection against depression. We use an intent-to-treat design, implemented via interrupted time-series methods, to test the hypothesis that the monthly incidence of suicide, a societally important distal measure of mental health in a population, decreased among Swedish men aged 50–59 after July 2013 when patent rights to sildenafil (i.e., Viagra) ceased, prices fell, and its use increased dramatically. The test uses 102 pre, and 18 post, price-drop months. 65 fewer suicides than expected occurred among men aged 50–59 over test months following the lowering of sildenafil prices. Our findings could not arise from shared trends or seasonality, biased samples, or reverse causation. Our results would appear by chance fewer than once in 10,000 experiments. Our findings align with theory indicating that sexual intimacy reinforces mental health. Using suicide as our distal measure of mental health further implies that public health programming intended to address the drivers of self-destructive behavior should reduce barriers to intimacy in the middle-aged populations.

Discussion

Our findings support the intuition and theory that sexual intimacy involving male erection protects against suicide among older men. Our methods ensure that this association could not arise from shared trends or seasonality, biased samples, or reverse causation. We further note that our finding would appear by chance fewer than once in 10 000 experiments (i.e., point estimate of − 4.66 with a standard error of 0.94) and that they align with theory indicating that sexual intimacy reinforces mental health.

Only replication can determine whether the association we found in Sweden describes other societies in which changes in patent rights affected the availability of sildenafil. We, however, know of no reason to suspect that the association would appear only in this cohort of Swedish men.

Although using suicide as an outcome connects our theory to an objective and important phenomenon, it likely leads to an underestimate of the association between low-priced sildenafil and mental health because suicide remains an extreme manifestation of diminished well-being. We could not, moreover, test for any unintended adverse health consequences (e.g., changes in sexually transmitted diseases).

Our methods do not estimate the efficacy of sildenafil in reducing an individual’s suicide risk. We assume that the rapid increase in the use of sildenafil among Swedish men in late 2013 arose in large part due to the availability of low-priced generic sildenafil. We, however, could not access monthly information on price, volume of prescriptions, or age of patients receiving these prescriptions. An important extension of our study would involve such data as well as longitudinal information on men’s mental health and likely mediating processes before and after July 2013. Such data would allow individual-level tests of whether and how the novel use of sildenafil improved mental health among men in their 50′s.

We speculate that the difference between expected and observed suicides declined below statistically detectable levels, although did not disappear, in 2015 for at least two reasons. The first assumes that lowering the price of sildenafil in 2013 likely reduced erectile dysfunction among men regardless of age. When men younger than 50 in 2013 eventually aged past 50, the sequelae of erectile dysfunction, including an increased risk of suicide, appeared lower among them than among men 50 to 59 when the price of sildenafil dropped.

Second, counterfactuals in tests that, like ours, use autocorrelation to arrive at expected values eventually “adjust” for interruptions with persistent effects. The effects, in other words, become statistically expected. Our test, for example, found autocorrelation such that an unexpected value at month t influences expectations for month t + 6. Our counterfactuals for 2015, therefore, reflected not only the pre-generic price months but also the lower-than-expected values observed in 2013 and 2014. We note, however, that the alternative approach of using forecasts in 2013 and 2014 to estimate expected values farther in the future would provide no more certainty than our approach because detection intervals in such models expand relatively quickly.

We did not hypothesize a detectable decline in suicide among women aged 50 to 59 because underlying causal processes, such as the etiology of depression [33], may differ between women and men. The failure to find an association, however, requires comment if for no other reason than sexual intimacy also relates to the mental health of women [7, 8]. Although the comparatively low incidence of suicide among women makes detecting differences over time less certain, we note that the null finding could arise from differences between men and women in the purpose and meaning of male erection as a component of intimacy at this stage of life [7]. For example, having and maintaining an erection may contribute directly to a man’s confidence and self-esteem [5], while insofar as this contributes to such self-perceptions among a female partner it would do so indirectly, as through a sense of desirability [34], with the respective effects possibly changing differentially with age across the genders [35]. The present data, however, do not enable us to do more than speculate on such possibilities. We can only acknowledge the complexity of the individual and contextual determinants of suicide rates and the need for further attention to the role that sexual intimacy plays in suicide, as encouraged by our strong epidemiologic findings.

Our results appear consistent with the general argument that many people enjoy sexual intimacy as a fundamental component of relationships that confer wellbeing and good mental health. Means to overcome erectile dysfunction could, therefore, promote restoration of a relational resource diminished by an inability to share desired forms of intimacy. These means likely include not only pharmaceutical treatment, but also individual or couple’s counselling, behavioral therapy [36], or even public policies (e.g., vacation legislation) that allow people more time for sexual intimacy. Insofar as salutary relationships remain important not only for the partners but also for the people around them and for the organizations to which they contribute, interventions such as greater access to sildenafil likely produce benefits to society.

We attribute positive outcomes more (e.g., economic growth) and negative outcomes less (like rising inequality) to our own political party than to an opposing party

It’s their fault: Partisan attribution bias and its association with voting intentions. Ethan Zell, Christopher A. Stockus, Michael J. Bernstein. Group Processes & Intergroup Relations, April 1, 2021. https://doi.org/10.1177/1368430221990084

Abstract: This research examined how people explain major outcomes of political consequence (e.g., economic growth, rising inequality). We argue that people attribute positive outcomes more and negative outcomes less to their own political party than to an opposing party. We conducted two studies, one before the 2016 U.S. presidential election (N = 244) and another before the 2020 election (N = 249 registered voters), that examined attributions across a wide array of outcomes. As predicted, a robust partisan attribution bias emerged in both studies. Although the bias was largely equivalent among Democrats and Republicans, it was magnified among those with more extreme political ideology. Further, the bias predicted unique variance in voting intentions and significantly mediated the link between political ideology and voting. In sum, these data suggest that partisan allegiances systemically bias attributions in a group-favoring direction. We discuss implications of these findings for emerging research on political social cognition.

Keywords: attribution, bias, motivation, politics, voting

Contrary to expectations, the suicide rate in the U.S. decreased in 2020, possibly due to a "we are all in the same boat" effect and an increased appreciation for life

Why Did U.S. Suicides Decrease in 2020? Kathryn Gordon. Psychology Today, Apr 5 2021. https://www.psychologytoday.com/intl/blog/out-the-ivory-tower/202104/why-did-us-suicides-decrease-in-2020

Preliminary 2020 data for U.S. mortality causes were published last week*. A startling statistic revealed an estimated 17.7% increase in deaths from 2019 to 2020. Approximately 344, 323 (10.3%) of those lives were lost directly due to COVID-19. While deaths related to heart disease, unintentional injury, diabetes, stroke, and Alzheimer's disease reportedly increased from 2019 to 2020, the number of suicides seemed to decrease by 5.6%. The decline in suicides may feel counterintuitive in the context of the rising U.S. suicide rates in recent years (with the exception of a decrease from 2018 to 2019) and the significant social, economic, and political stresses faced by many people in 2020. 

* The Leading Causes of Death in the US for 2020. Farida B. Ahmad, Robert N. Anderson. JAMA, Mar 31 2021. https://jamanetwork.com/journals/jama/fullarticle/2778234

 

“Time Slows Down Whenever You Are Around” for Women but Not for Men

“Time Slows Down Whenever You Are Around” for Women but Not for Men. Joana Arantes et al. Front. Psychol., April 6 2021 | https://doi.org/10.3389/fpsyg.2021.641729

Abstract: What happens when we unexpectedly see an attractive potential partner? Previous studies in laboratory settings suggest that the visualization of attractive and unattractive photographs influences the perception of time. The major aim of this research is to study time perception and attraction in a realistic social scenario, by investigating if changes in subjective time measured during a speed dating are associated with attraction. The duration of the dates was variable and participants had to estimate the time that passed. Among other measures, participants also rated the potential partners in terms of their physical attractiveness before and after the dates and reported if they would like to exchange contact with them. Results showed that, in a real speed dating situation, when there is a perception of the partner as being physically more attractive, women tend to overestimate the duration of that meeting, whereas men tend to underestimate its duration. Such changes may reflect evolutionary adaptations which make the human cognitive system more responsive in situations related to reproductive fitness.

Discussion

The main objective of this research was to study time perception and attraction in a realistic social scenario by investigating if changes in subjective time measured during a speed dating session were related with attraction. The duration of the dates was variable and participants had to estimate the time that passed. Participants were asked to rate potential partners in terms of their physical attractiveness before and after the dates and to report if they wanted to exchange contacts with them. Our data suggest, consistently with our hypotheses, that the estimated time of the dates were associated with the physical attractiveness of the potential partners perceived by participants.

More specifically, our results showed that the more females rated a potential partner as physically attractive, the longer they perceived the duration of the date. That goes along with the popular idea that “time slows down whenever you are around” (Swift, 2010). This may be due to a bigger allocation of women’s cognitive resources to process more information of the meeting (Loftus et al., 1987) and of the potential partner they are interested in. More specifically, even though physical attractiveness is important in a potential partner, for women there are other characteristics that may have a higher value, such as good economic prospects (Buss and Barnes, 1986; Bech-Sørensen and Pollet, 2016). Therefore, searching for cues of positive traits in a potential mate requires the use of cognitive resources. Besides that, research has shown that when women perceive the partner as attractive, they tend to be more motivated to make a good impression on the partner and pay more attention to the things they say that might influence this impression (Dong and Wyer, 2014). According to Ornstein’s storage size model (Ornstein, 1969; Sasaki and Yamada, 2017), when people store more information in memory, they tend to perceive the duration of that interval of time as being longer. Furthermore, women may consider the experience with a partner who they consider physically attractive as positive in an emotional way. This result is also consistent with that study of Kellaris and Kent (1992) in which time did seems to slow downs when participants were exposed to positively valenced music, compared to participants exposed to negatively valenced music. The authors suggested that when people receive positive emotional information they tend to invest more cognitive resources in listening to music. Therefore, they tend to perceive the received stimulus information as larger and remember the event as being longer. Besides that, a study conducted by Zhang et al. (2017) showed a reliable sex differences in temporal distortion with an emotional stimulus. Women, compared to men, tended to overestimate the durations of emotional words.

However, for men, our results showed that time does not seems to slow down whenever someone attractive is around. In fact, the more males rated a female participant as physically attractive, the shorter they perceived the duration of the speed date. This seems to be consistent with the idea that “time flies when you are having fun.” Research has shown that men’s preferences for potential mates are based mostly in physical attractiveness (Lippa, 2007; Todd et al., 2007; Eastwick et al., 2011). Therefore, when they have a meeting with a potential partner that they perceive as being physically attractive, they do not need to spend much cognitive resources searching for other cues, feeling automatically motivated to be with her. Consequently, they will tend to estimate the time that passed as being shorter. This result also suggests that time perception in males during the dates may be affected by motivation because, according to previous literature, positive approach motivation causes the perception of time to be shorter (Glabe and Poole, 2012). Besides that, the subjective perception of the passage of time seems to be an important component to evaluate the experience of boredom (Danckert and Allman, 2005). So, when males are interested and motivated in the date with a physical attractive potential partner, they tend to estimate the date duration as shorter and, on the other hand, this time underestimation reinforces the perception of an interesting date (Sackett et al., 2010). Underestimation of the duration of the date may prolong approach-motivated behavior (Glabe and Poole, 2012) and this increases the probability of a successful mating. On time, Einstein said “Put your hand on a hot stove for a minute and it seems like an hour. Sit with a pretty girl for an hour, and it seems like a minute.”

According to Trivers’ (1972) theory, the relative parental investment of the sexes in their offspring is the key variable controlling the operation of sexual selection. Sexual intercourse for a male is a small investment, but for a female can produce a 9-month investment, at least. For a female, this investment requires more choosiness in the partner choice. Besides that, prior research showed that females tend to be more selective (Kurzban and Weeden, 2005) and more discriminating (Todd et al., 2007) than males. Therefore, it is expected that females allocate more attention to capturing a greater number of characteristics of the potential partner in addition to physical attractiveness, such as intelligence, personality, earning prospects and other signs suggesting he could be good partner in the future. This process seems to imply an exhaustive evaluation in the first meeting which requires the allocation of a lot of cognitive resources. On the other hand, men are attracted by fewer characteristics of the partner compared to females (Luo and Zhang, 2009). So, males do not use so much energy and resources in cognitive processing of information and focus more energy in having fun with the partners they perceived as being more attractive. Such changes may reflect evolutionary adaptations which make the human cognitive system more responsive in situations related to reproductive fitness.

Williams (2012) suggested that sex differences in timing might be due to the effects of circulating estrogen in adult females versus testosterone in adult males. Besides that, gonadal hormones had been found to influence sexual motivation (Wallen, 2001). In men, testosterone increases interest in a woman, engagement in self-presentation, smiling and making eye contact (Roney et al., 2006; Meij et al., 2011; Thornhill et al., 2013). Meij et al. (2011) suggested that during encounters with the opposite sex, testosterone may promote the display of affiliative behaviors that increase a man’s mating prospects and during social contact with a potential partner testosterone is linked to the initiation of courtship behaviors. On the other hand, in women, estradiol seems to be a significant positive predictor of sexual desire (Puts et al., 2013; Roney and Simmons, 2013).

Estradiol is one of the natural estrogens and has been shown to increase striatal dopamine release, that may modify temporal perception and timing performance in a manner similar to indirect dopamine agonists such as amphetamine and cocaine (Pleil et al., 2011). Estrogen as a dopamine agonist facilitates striatal dopaminergic activity (Sandstrom, 2007), stimulating the dopaminergic transmission and, consequently, producing an overestimation of time intervals (Cheng et al., 2006). Pleil et al. (2011) investigated sex differences in the rapid and acute effects of estradiol on time perception in adult male and female rats. According to the authors, their results are consistent to the idea that there are multiple mechanisms of estrogen’s action in the striatum that modulate dopaminergic activity and are differentially organized by gonadal steroids during early brain development. Additionally, Becker (1999) found that striatal dopaminergic release is affected by estrogen only in females. The striatum is one of the components of the basal ganglia that have been suggested to be a fundamental component of the neural basis of timing (Ivry and Spencer, 2004) and multiple studies, specifically with patients with dopamine system disorders as Parkinson (Leranth et al., 2000; Michel et al., 2002), and schizophrenia (Seeman and Lang, 1990; Riecher-Rössler and Häifner, 1993; Michel et al., 2002) and others, found an interaction between gonadal steroid hormones such as estrogen in basal ganglia mechanisms (Hartesveldt and Joyce, 1986). Therefore, because of the fact that estrogen is a predictor of sexual desire and sexual motivation, this may increase their circulation in women during a speed date with physically attractive partners and, subsequently, increase dopamine release in striatum. Besides that, some studies found that women, on average, have higher presynaptic dopamine synthesis capacity (Laakso et al., 2002) and lower D2 receptor affinity (Pohjalainen et al., 1998) that suggests an increased endogenous dopamine in women’s striatum, comparing to men. So, neural sex differences in dopaminergic circuits in the striatum could explain this sex difference on the influence of physical attractiveness in time perception. It is thus possible that sexual hormones on males have an opposite effect in striatum (Myers et al., 2003).

Our results may diverge from Dong and Wyer (2014) study because sex differences in their study could be masked by lack of cues in the interaction that could influence attraction mechanisms. Specifically, the reduction of non-verbal information may influence the response of females more than males because, according to a vast literature (Mehrabian, 1972; Mehrabian and Ksionzky, 1972; Zahn, 1973, 1975), females are more sensitive to non-verbal information and males to a verbal information.

Our study also demonstrates that for the decision of exchanging or not contact with the partner, physical attractiveness seems to be an important factor for both sexes because when participants perceived the partners as physically attractive, they tended to exchange contacts with them. In addition, consistent with our second hypothesis, the physical attractiveness of the potential partner perceived by the participant changes according to the interest in exchanging contact with him/her. In other words, interest or not in the meeting with a potential partner and the desire or not to keep in contact in the future influences their perceived physical attractiveness. Particularly, when participants are interested in a potential partner at the end of the date, they perceive their physical attractiveness as being higher compared to the initial evaluation (i.e., before the date). When participants are not attracted to partners at the end of the date, expressing the desire not to exchange contacts with them, they not change their evaluation of the potential partner’s physical attractiveness. These results suggest that there may be an effect of other characteristics of the potential partner in the evaluation of physical attractiveness. This is supported by some laboratory studies that have shown that the evaluated attractiveness of opposite-sex people is influenced by their personality. For example, Lewandowski et al. (2007) found that when a person was presented with positive personality information about the person shown in a photograph, participants rated that person as more physically attractive and when photographs were paired with negative personality information the person depicted was rated as less physically attractive. These results are also consistent with Kniffin and Wilson’s (2004) naturalistic studies that showed that non-physical characteristics such as familiarity, liking, respect, talent, and effort have a great influence on physical attraction judgments.

Limitations and Future Research

First, previous studies found that preferences in mate selection are influenced by the type of desired relationship, short or long-term. Thus, in future research it seems relevant to question participants in the speed dating event about whether they would like to have a short or long-term relationship with the partners they show an interest in exchanging contacts with. Second, this research shows that in a realistic scenario where two people meet each other, changes occur in time perception and it seems plausible to us that other implicit cognitive processes are affected in this context. However, there are no studies about other implicit measures in speed dating events, such as memory or attention, and future research should focus on this theme. Third, in terms of time perception and attractiveness, our data were correlational, so do not provide evidence for a causal influence of physical attractiveness on timing. Our results suggest that the two variables are associated but it would be interesting to understand if there is a causal relation between them. Third, there were 32 (18.50%) exchanges of contact details but only three intimate relationships were formed and lasted at least 6 months. It would be interest to investigate in future studies which variables have contributed to the development of an intimate relationship after the speed-dating. Fifth, participants were relatively young people, which may represent a limitation of the present study. Research has shown that men tend to prefer females at the age at which fertility peaks in order to increase their reproductive success (Conroy-Beam and Buss, 2019). In future research, it seems important to understand if the results of this study are applicable to older ages, in particular in postmenopausal women. If time perception in dating situations is an adaptive mechanism for mating, this bias should no longer occur in post-reproductive, menopausal women (Cyrus et al., 2011). Finally, our results based on stepwise multiple regression analyses showed that the attraction felt toward the partner was the strongest and unique predictor of both men’s and women’s perceptions of date duration. These results support the idea that when individuals are exposed to opposite-sex persons to whom they feel an attraction, their timing system is affected – women tend to overestimate, whereas men tend to underestimate the passage of time. However, it is still important to notice the weak explanatory power of the models, which indicates that there are other contributing factors to time perception that need to be explored in future research.

Sex differences in brain in response to midlife stress linked to fetal stress exposures

Impact of prenatal maternal cytokine exposure on sex differences in brain circuitry regulating stress in offspring 45 years later. Jill M. Goldstein et al. Proceedings of the National Academy of Sciences, April 13, 2021 118 (15) e2014464118. https://doi.org/10.1073/pnas.2014464118

Significance: Clinical research and animal models have demonstrated a significant connection between maternal stress during pregnancy and sensitivity to stress in offspring, leading to increased susceptibility to neuropsychiatric disorders later in life. In a unique prenatal cohort that was followed for over four decades, we tested associations between pro- and anti-inflammatory markers in maternal prenatal sera and sex differences in neural responses to negative stress in the offspring in early midlife using functional MRI. Men and women exposed in utero to abnormal levels of pro-inflammatory cytokines and to an imbalance of pro- to anti-inflammatory influences showed dysregulation of stress response circuitry 45 y later, with sex-dependent effects.

Abstract: Stress is associated with numerous chronic diseases, beginning in fetal development with in utero exposures (prenatal stress) impacting offspring’s risk for disorders later in life. In previous studies, we demonstrated adverse maternal in utero immune activity on sex differences in offspring neurodevelopment at age seven and adult risk for major depression and psychoses. Here, we hypothesized that in utero exposure to maternal proinflammatory cytokines has sex-dependent effects on specific brain circuitry regulating stress and immune function in the offspring that are retained across the lifespan. Using a unique prenatal cohort, we tested this hypothesis in 80 adult offspring, equally divided by sex, followed from in utero development to midlife. Functional MRI results showed that exposure to proinflammatory cytokines in utero was significantly associated with sex differences in brain activity and connectivity during response to negative stressful stimuli 45 y later. Lower maternal TNF-α levels were significantly associated with higher hypothalamic activity in both sexes and higher functional connectivity between hypothalamus and anterior cingulate only in men. Higher prenatal levels of IL-6 were significantly associated with higher hippocampal activity in women alone. When examined in relation to the anti-inflammatory effects of IL-10, the ratio TNF-α:IL-10 was associated with sex-dependent effects on hippocampal activity and functional connectivity with the hypothalamus. Collectively, results suggested that adverse levels of maternal in utero proinflammatory cytokines and the balance of pro- to anti-inflammatory cytokines impact brain development of offspring in a sexually dimorphic manner that persists across the lifespan.

Keywords: prenatal immune programmingprenatal stressstress circuitrysexfunctional brain imaging

Press release: Sex differences in brain in response to midlife stress linked to fetal stress exposures --- Exposure to inflammatory substances in the womb due to prenatal stress differentially affects stress circuitry function in male and female offspring, which is retained into midlife. https://www.eurekalert.org/pub_releases/2021-04/mgh-sdi040121.php

Naïve, unenculturated chimpanzees fail to make and use flaked stone tools

Naïve, unenculturated chimpanzees fail to make and use flaked stone tools. E Bandini et al. European Human Behaviour and Evolution Association, 15th Conference, Mar 2021. https://ehbea2021.com/

Abstract

Objective: Despite extensive research on early hominin lithic technology, the mechanisms underlying flake manufacture and use are still debated. To draw phylogenetic inferences on the potential cognitive processes underlying these abilities in early hominins, we examined whether our closest living relatives, chimpanzees (Pan troglodytes), could learn to make and use flakes.

Methods: We provided naïve unenculturated chimpanzees from two independent populations (n=11) with baited puzzle boxes that could only be accessed with cutting tools, stone cores, and hammerstones to test for their ability to spontaneously make and use flakes.

Results: Despite the fact that the chimpanzees demonstrated an understanding of the requirements of the task and were sufficiently motivated, none of the chimpanzees made or used flakes in any of the experimental conditions.

Conclusions: These results differ from previous ape flaking experiments, which found flake manufacture and use in bonobos and one orangutan. However, these earlier studies tested only enculturated apes and provided them with demonstrations. The contrast between these earlier positive findings and our negative findings (despite using a much larger sample size) suggests that enculturation and/or human demonstrations may be necessary for chimpanzees to acquire these abilities. The data obtained here is consistent with the hypothesis that flake manufacture and use might have evolved in the hominin lineage after the split between Homo and Pan 7 million years ago, a  scenario further supported by the apparent absence of flaked stone tools in the archaeological record after this split.

Intent-based morality in Colombian and Spanish children: Punishment & retribution

Intent-based morality in Colombian and Spanish children. RL Arini et al. European Human Behaviour and Evolution Association, 15th Conference, Mar 2021. https://ehbea2021.com/

Abstract

Objective: The majority of the developmental literature about the role of outcomes and intentions in moral evaluations has been conducted on English-speaking children and focused on harm and property transgressions. We aimed at investigating this phenomenon in 5- to 11-year-olds from collectivistic Colombia and individualistic Spain (N=123) employing moral scenarios involving disloyalty and unfairness.

Methods: We developed a computer game showing internet players violate moral norms; children took the role of referees and had the opportunity to judge and punish the players for their behaviour.

Results: Regarding judgements of transgression severity, Colombian children judged failed intentional transgressions more severely than accidental transgressions in case of disloyalty, but not yet in case of unfairness. Regarding punishment severity, Spanish children began to punish failed intentional transgressions of both moral domains more severely than accidents around 8 years of age. While punishment severity decreased with increasing age for both unfairness and disloyalty in Spanish children, in Colombian children the downward pattern was observed only for unfairness. Additionally, children anticipated punishment to feel worse than how it actually felt during and after punishment allocation.

Conclusions: According to cultural group selection, it makes evolutionary sense that children’s sensitivity to intentionality develops earlier within the moral domains (loyalty) privileged by their own (collectivistic) cultures. Moreover, selective concerns for one moral domain (loyalty) over another (fairness) may become more pronounced with development because of culture-directed learning processes. The lack of hedonic punishment expectations suggests that retribution is unlikely to be the primary driver of children’s third-party punishment.

Even though inaccurate beliefs lead to costly mistakes, people interpret favorable feedback to be more informative; author casts a new light on the origins of overconfidence & the mechanisms that perpetuate it in the face of feedback

Belief-Based Utility and Signal Interpretation. Marta Kozakiewicz. February 23, 2021. https://marta-kozakiewicz.github.io/assets/kozakiewicz_jmp.pdf

Rolf Degen's take: https://twitter.com/DegenRolf/status/1378975549058646018

Abstract: People tend to overestimate their abilities and chances of success, even though inaccurate beliefs lead to costly mistakes. How can these beliefs persist in an environment with frequent feedback? I propose a new test of the hypothesis that people interpret favorable feedback to be more informative. Using experimental data, I provide the first causal evidence that the utility from beliefs affects one’s perception of signal informativeness. To establish causality, I adopt a matching estimator approach and construct a counterfactual outcome of a subject who observes the same signal, but the signal is not affecting his belief-based utility. I find a strong and significant effect: subjects interpret favorable signals to be more informative due to changes in belief-based utility. The results cast a new light on the origins of overconfidence and illuminate mechanisms that perpetuate it in the face of feedback.

Keywords: overconfidence, belief formation, learning, experiment

JEL classification: C91, D83

Claims About The Hidden Cost of Religiosity and the Gender Wage Gap

The Hidden Cost of Prayer: Religiosity and the Gender Wage Gap. Traci Sitzmann and Elizabeth M. Campbell. Academy of Management Journal, Oct 27 2020. https://doi.org/10.5465/amj.2019.1254

Abstract: Religion is a preeminent social institution that meaningfully shapes cultures. Prevailing theory suggests that it is primarily a benevolent force in business, and differences across world religions preclude examining effects that thread across religions. We develop a theoretical account that fundamentally challenges these assumptions by explaining how and why religiosity—regardless of which religion is prominent—differentiates based on gender, widening the gender wage gap. Guided by an integrated review of the religion literature, we specify three dimensions of gender differentiation—social domains, sexuality, and agency—that explain why religiosity widens the gender wage gap. A series of studies tested our theoretical model. Two studies showcased the predictive power of religiosity on the gender wage gap across 140 countries worldwide and the 50 United States via gender-differentiated social domains, sexuality, and agency, explaining 37% of the variance in the wage gap. U.S. longitudinal data indicated the gender wage gap is narrowing significantly faster in secular states. Moreover, experiments allowed for causal inference, revealing that gender-egalitarian interventions blocked the effect of religiosity on the gender wage gap. Finally, theoretical and empirical evidence converge to suggest that religiosity’s effect on the gender wage gap applies across the major world religions.

Do EITC expansions pay for themselves? Effects on tax revenue and government transfers

Do EITC expansions pay for themselves? Effects on tax revenue and government transfers. Jacob E. Bastian, Maggie R. Jones. Journal of Public Economics, Volume 196, April 2021, 104355. https://doi.org/10.1016/j.jpubeco.2020.104355

Highlights

• The EITC increases the labor supply of mothers, which leads to increases in payroll and sales taxes paid.

• The EITC decreases dependence on government transfer spending.

• Evaluated over a one-year period, the net EITC cost is only 17 percent of the $70 billion annual budgetary cost.

• Evaluated over a longer-time horizon, the net EITC cost is lower and perhaps zero.

• The 2009 EITC expansion continued to increase maternal labor supply and earnings.

Abstract: This paper calculates the EITC’s net cost by estimating effects, both direct and through recipients’ behavioral changes, on tax revenue and government transfer spending. We show that the EITC increases labor supply and income, thereby increasing the taxes households pay and reducing the government transfer payments they receive. Using linked IRS–CPS data and several EITC policy changes, and focusing on married and unmarried women, we find that the EITC’s net cost is only 17 percent of the ($70 billion) budgetary cost over a one-year period. Although the EITC is one of the U.S.’s largest and most important public assistance programs, the EITC is actually one of the U.S.’s least expensive anti-poverty programs.

Keywords: Earned income tax creditTaxesPublic assistanceGovernment transfersWomen’s labor supplyFiscal policy

The ‘Big Gods Hypothesis’ offered a solution to the origins of religion & of complex societies by proposing that beliefs in moralizing supernatural punishment culturally evolved to facilitate cooperation among strangers

Whitehouse, Harvey, Pieter François, Daniel Hoyer, Kevin C. Feeney, Enrico Cioni, Rosalind Purcell, Robert M. Ross, et al. 2021. “Big Gods Did Not Drive the Rise of Big Societies Throughout World History.” OSF Preprints. April 3. doi:10.31219/osf.io/mbnvg

Abstract: The origins of religion and of complex societies represent evolutionary puzzles. The ‘Big Gods Hypothesis’ offers a solution to both puzzles by proposing that beliefs in moralizing supernatural punishment culturally evolved to facilitate cooperation among strangers in large-scale societies. Although previous research has suggested an association between the presence of Big Gods and big societies, the relationship between the two is disputed, and attempts to establish causality have been hampered by limitations in the availability of detailed global longitudinal data. To address these issues, we analyze data in the Seshat Global History Databank that coded 309 past societies for variables capturing beliefs in moralizing supernatural punishment and social complexity. The longitudinal (time-resolved) nature of Seshat data enables us to test evolutionary hypotheses about processes generating social change and distinguish between competing causal scenarios. We find that beliefs in moralizing supernatural punishment only appear after the largest increases in social complexity and that a formal analysis designed to test for causal relationships failed to detect a statistically significant effect of moralizing supernatural punishment on social complexity.

Anxiety sensitivity, female sex, and smoking are risk factors for physical inactivity; high levels of anxiety sensitivity were related to more time spent walking for females but not males

Understanding sex differences in physical activity behavior: The role of anxiety sensitivity. Gloria J. Gomez et al. Mental Health and Physical Activity, March 29 2021, 100392. https://doi.org/10.1016/j.mhpa.2021.100392

Highlights

• Anxiety sensitivity, female sex, and smoking are risk factors for physical inactivity.

• Higher anxiety sensitivity levels were related to lower total physical activity levels in males.

• Females' total physical activity levels were not dependent on anxiety sensitivity levels.

•High levels of anxiety sensitivity were related to more time spent walking for females but not males.

Abstract

Problem: There is a well-evidenced sex-disparity in physical activity (PA), such that females are significantly less active than males. Anxiety sensitivity, the fear of anxiety-related bodily sensations, is a cognitive-affective vulnerability associated with increased negative affect during PA and lower levels of PA. The current study examined anxiety sensitivity as a potential sex-specific, psychological factor related to sex differences in past-week PA behavior in daily cigarette smokers.

Method: Participants (n=527; 53.3% female) completed an anonymous online survey on emotion and health. Anxiety sensitivity was assessed with the Anxiety Sensitivity Index-3. Past-week, self-reported PA minutes were measured across four intensities (e.g. walking, moderate, vigorous, and total PA) using the International Physical Activity Questionnaire-Short. Four zero-inflated negative binomial regression models were constructed to test the main and interactive effects of sex and anxiety sensitivity on PA outcomes.

Results: Females reported significantly fewer past-week PA minutes relative to males across all domains. At higher levels of anxiety sensitivity, males reported significantly fewer total PA minutes; whereas, total PA levels in females were not dependent on anxiety sensitivity level. Additionally, females with elevated anxiety sensitivity reported significantly more past-week walking minutes relative to females with low anxiety sensitivity, whereas the opposite pattern was observed in males.

Conclusion: This is the first study to our knowledge to examine sex-differences in anxiety sensitivity and PA, at varying PA intensities, among smokers. These data have the potential to inform sex-specific models of anxiety, PA, and smoking.

Keywords: ExercisePhysical activityAnxiety sensitivitysex differencesSmokers