Find higher fertility among men with higher cognitive ability among Swedish men using taxation & conscription registers; low income & low cognitive ability independently predict low fertility & high childlessness

Do income and marriage mediate the relationship between cognitive ability and fertility? Data from Swedish taxation and conscriptions registers for men born 1951–1967. Martin Kolk, Kieron Barclay. Intelligence, Volume 84, January–February 2021, 101514. https://doi.org/10.1016/j.intell.2020.101514

Highlights

• We find higher fertility among men with higher cognitive ability among Swedish men using population-level taxation and conscription registers

• Low income and low cognitive ability independently predict low fertility and high childlessness

• Strong evidence of lower access to marriage and reproduction among low status men in contemporary Sweden

Abstract: Recent evidence suggests a positive association between fertility and cognitive ability among Swedish men. In this study we use data on 18 birth cohorts of Swedish men to examine whether and how the relationship between cognitive ability and patterns of childbearing are mediated by income, education and marriage histories. We examine whether the expected positive associations between cognitive ability and life course income can explain this positive association. We also explore the role of marriage for understanding the positive gradient between cognitive ability and fertility. To address these questions we use Swedish population administrative data that holds information on fertility histories, detailed taxation records, and data from conscription registers. We also identify siblings in order to adjust for confounding by shared family background factors. Our results show that while cognitive ability, education, income, marriage, and fertility, are all positively associated with each other, income only explains a part of the observed positive gradient between fertility and cognitive ability. We find that much of the association between cognitive ability and fertility can be explained by marriage, but that a positive association exists among both ever-married and never-married men. Both low income and low cognitive ability are strong predictors of childlessness and low fertility in our population. The results from the full population persist in the sub-sample of brothers.

Keywords: FertilityChildlessnessCognitive abilityIncomeSweden

6. Discussion

In our paper, we show that while income is strongly associated with cognitive ability, men with below average cognitive ability have fewer children, even after adjusting for income. We also find that these differences are magnified for childlessness, and are also very strong for entry into marriage. Consistent with previous research, we find that income and fertility are very strongly associated (Chudnovskaya, 2019; Kolk, 2019), but that the relationship between cognitive ability and fertility persists net of the mediation of income. This is particularly true at lower income levels. Men with low cognitive ability who are above the median in cumulative income between age 18 and 45 have approximately the same number of children as men who score highly on cognitive ability. However, men with low cognitive ability are much less likely to find themselves in the top half of the cumulative income distribution. Among ever-married individuals, the association between cognitive ability and fertility is strongly attenuated, and only really suggests lower fertility among men with the lowest scores on cognitive ability. When comparing full biological brothers with each other, we find a strong positive fertility and cognitive ability gradient even after adjusting for income. Overall, our results indicate that the primary reason that we observe low fertility among men with lower cognitive ability is because of their failure to attract a partner for stable unions for childbearing. In addition to confirming previous findings on cognitive ability and fertility in Sweden (Kolk & Barclay, 2019), the findings of this study provide evidence for the importance of partnership formation for fertility, as well as showing that the intelligence-fertility association persists even after taking cumulative income into account.

Another intriguing empirical pattern that we have observed is that, although men with high cognitive ability have more children overall, men of average cognitive ability had more children than men with high cognitive ability scores among those who never married. These never-married men with high cognitive ability are too few to affect the population-level intelligence-fertility gradient, but may indicate a sub-population that either voluntarily abstains from childbearing and marriage, or in other ways have life trajectories that are associated with high education and income but not traditional patterns of family formation. In our full population analyses, when adjusting for cumulative income, we find that the men with the highest cognitive ability scores have slightly lower fertility and higher childlessness than men with median cognitive ability scores. After adjusting for income we observe slightly lower fertility among high IQ never-married men (left-panels of Fig. 6, Fig. 7), as well as slightly lower fertility among men with high cognitive ability (see Fig. 1). However, our finding that higher cognitive ability men have higher childlessness and lower fertility than men with similar incomes but average cognitive ability is not replicated in sibling comparison models.

In our sibling comparison models we consistently observe lower fertility among men in the bottom half of the cognitive ability distribution. The difference between our population level models and the sibling models is intriguing. Although the results from our population level models are key to understanding how cognitive ability may be distributed in the following generation (though without data on women we cannot speculate about this), the sibling comparison models effectively adjust for all factors shared in the family of origin. It is certainly possible that the results in the full population are confounded by factors that are jointly associated with both cognitive ability as well as fertility outcomes, for example negative experiences in early adulthood such as health shocks or substance abuse.

We believe that our study highlights the importance of examining and interpreting gross associations between cognitive ability and fertility by taking account of the associations between cognitive ability and mediating dimensions of social status and partnership formation. The sociological and demographic literature suggests great variation across the West in the associations between income and fertility, and education and fertility. The findings from our Swedish data may not generalize to other countries. In other high-income countries, the interrelationships between education, income, marriage, and fertility, differ in important ways from Sweden, and our results may to some extent be contingent on the aggregate positive relationships between status and marriage and family formation in Sweden. Nevertheless, we think that the fertility disadvantage of very low cognitive ability men is likely widespread across OECD contexts and that using datasets where such individuals are fully included is important if researchers are to be able to make population-level inferences. Future research on cognitive ability and fertility is therefore advised to pay careful attention to contemporary research in family sociology, demography, and economics on the overall relationship between status and fertility in the focal society. Importantly, the associations between income and fertility and education and fertility typically differ by gender. Unfortunately, we cannot examine any gender differences in the intelligence-fertility gradient in Sweden as we have male-only conscription data.

Our findings also contribute towards the increasing evidence for social polarization of childbearing in many Western countries. We find that the proportion childless and the proportion that never-marry is very substantial among men with lower cognitive ability. We find large separate effects where both low income and low cognitive ability are each strongly associated with a higher probability of childlessness and low completed fertility. When a man has both low income and low cognitive ability, fertility is even lower. This corresponds to the findings from a growing literature that shows that men with low income, low levels of education, worse health, and low cognitive ability, are much less likely to find a childbearing partner in Scandinavia (Barclay & Kolk, 2020; Jalovaara et al., 2019; Jalovaara & Fasang, 2020; Kolk, 2019). Fertility in Scandinavia has traditionally been characterized by relatively small social differences between groups. Our findings of differences by cognitive ability in probabilities of childlessness and ever-marriage of 20 to 30 percentage points clearly show that partnership and childbearing are increasingly less likely for many men with low cognitive ability in contemporary Sweden.

Global trends in the prevalence and incidence of depression: There is a predominant increasing trend in its prevalence over time

Global trends in the prevalence and incidence of depression: a systematic review and meta-analysis. Darío Moreno-Agostino et al. Journal of Affective Disorders, Volume 281, 15 February 2021, Pages 235-243. https://doi.org/10.1016/j.jad.2020.12.035

 

Highlights

• There is a predominant increasing trend in depression prevalence over time

• The increase is not attributable to methodological changes within or across studies

• Studies on depression incidence change with similar designs over time are needed

Abstract

Background: There is mixed evidence regarding the change in the prevalence of depression in the general population over time. This study aimed to synthesise the evidence on studies that use equivalent approaches in equivalent populations across different time points.

Methods: A systematic review was conducted to identify studies focused on the change over time in depression incidence and prevalence in the general population. A random-effects meta-analysis was performed to obtain a pooled effect for the change in the prevalence estimates between the first and last time points considered. Subgroup and meta-regression analyses were used to ascertain differences in the effect sizes by gender, age group, prevalence type, elapsed time between cross-sections, and depression operationalisation.

Results: 19 studies provided information on the change in depression prevalence over time, whereas none provided such information regarding incidence. The pooled odds ratio (OR) and confidence interval (CI) were estimated by using 17 studies: OR=1.35 (95% CI: 1.14, 1.61). Similar pooled effects were obtained for females and males, separately. The high heterogeneity across studies was not explained by any of the design variables considered. No evidence for publication bias was found.

Limitations: The review included published articles up to August 2018, and the information of studies with more than two time points was summarised in a single estimate of change.

Conclusions: There is a predominant increasing trend in the likelihood of experiencing depression over time that seems not to be explainable by study design differences or publication bias alone.

Keywords: depressionmeta-analysismood disorders

People tend to like interpersonal behaviors that are similar to their own and become bothered by behaviors that are the opposite of their own, consistently across different levels of relationship closeness

An Interpersonal Approach to Social Preference: Examining Patterns and Influences of Liking and Being Bothered by Interpersonal Behaviors of Others. Tianwei V. Du, Katherine M. Thomas and Donald R. Lynam. Journal of Personality Disorders, December 2020. https://guilfordjournals.com/doi/abs/10.1521/pedi_2020_34_496

Abstract: Personality disorders are rooted in maladaptive interpersonal behaviors. Previously, researchers have assessed interpersonal behaviors using self-ratings of one's own behaviors and third-person ratings of dyadic interactions. Few studies have examined individuals’ perceptions of others’ interpersonal behaviors. Using a sample of 470 undergraduate students, the authors examined patterns of interpersonal perception as well as influences of these patterns on psychological functioning. Findings showed that people tend to like interpersonal behaviors that are similar to their own and become bothered by behaviors that are the opposite of their own. Such a pattern is particularly characteristic on the warmth dimension and is consistent across different levels of closeness of the relationship. The authors also found small but significant effects of interpersonal perception on personality and general psychological functioning, above and beyond effects of individuals’ own interpersonal traits. Such findings highlight the importance of including perceptions of others in investigating interpersonal dynamics when understanding personality disorders.

Teams of mostly women performed better than teams of mostly men, when negative relationships existed among team members

When Can Negativity Mean Success? Gender Composition, Negative Relationships and Team Performance. Bret Bradley, Sarah Henry, Benjamin Blake. Small Group Research, December 11, 2020. https://doi.org/10.1177/1046496420959446

Rolf Degen's take: https://twitter.com/DegenRolf/status/1338744287836647424

Abstract: Teams are often plagued by internal discord, such as negative relationships, which can impede successful team performance. While most teams eventually encounter negative relationships, we have limited knowledge on how teams manage this negativity. In this article, we expand scholarship on teams by exploring an inherent team characteristic, gender composition, to assess its role in how teams cope with negative relationships. On the one hand, social role theory suggests that teams comprised of more women will perform better in the presence of negative relationships. On the other hand, theories and evidence on personality and individual differences suggest that teams comprised of more men will perform better in the presence of negative relationships. We studied 151 student project teams, and found that teams of mostly women performed better than teams of mostly men, when negative relationships existed among team members. We discuss the implications of these findings for research and practice.

Keywords: gender composition, negative relationships, team performance, social role theory

Social information is immensely valuable, but lots of it is wasted (we fail to give such information its optimal weight); egocentric discounting is a pervasive effect, but we have single unifying explanation for it

Morin, Olivier, Pierre O. Jacquet, Krist Vaesen, and Alberto Acerbi. 2020. “Social Information Use and Social Information Waste.” SocArXiv. December 10. doi:10.1098/rstb.2020.0052

Abstract: Social information is immensely valuable. Yet we waste it. The information we get from observing other humans and from communicating with them is a cheap and reliable informational resource. It is considered the backbone of human cultural evolution. Theories and models focused on the evolution of social learning show the great adaptive benefits of evolving cognitive tools to process it. In spite of this, human adults in the experimental literature use social information quite inefficiently: they do not take it sufficiently into account. A comprehensive review of the literature on five experimental tasks documented 45 studies showing social information waste, and 4 studies showing social information being over-used. These studies cover “egocentric discounting” phenomena as studied by social psychology, but also include experimental social learning studies. Social information waste means that human adults fail to give social information its optimal weight. Both proximal explanations and accounts derived from evolutionary theory leave crucial aspects of the phenomenon unaccounted for: egocentric discounting is a pervasive effect that no single unifying explanation fully captures. Cultural evolutionary theory’s insistence on the power and benefits of social influence is to be balanced against this phenomenon.

The Role of Subjective and Objective Social Status in the Generation of Envy: Those who were the most respected in the eyes of others were envied more than the richest ones

The Role of Subjective and Objective Social Status in the Generation of Envy. Henrietta Bolló, Dzsenifer Roxána Háger, Manuel Galvan and Gábor Orosz. Front. Psychol., December 15 2020. https://doi.org/10.3389/fpsyg.2020.513495

Abstract: Envy is a negative emotion experienced in response to another person’s higher status. However, little is known about the composition of its most important element: status. The present research investigates the two main forms of social status (objective and subjective) in the generation of envy. In Study 1, participants recounted real-life situations when they felt envious; in Study 2 we examined whether the effect was the same in a controlled situation. We consistently found that those who were the most respected in the eyes of others were envied more than the richest ones. Furthermore, perceived deservingness of the superior other’s success differentiated between benign and malicious envy. Although previous studies focused on material comparisons when investigating envy, our results indicate that envy is rather a subjective social status related emotion. Not material, but social advantage of the superior other causes the most painful envy and future studies should put more emphasis on this type of social comparison in envy research.

General Discussion

According to the social-functional approach to envy, the goal of envy is to lessen the social status gap between the self and a superior other (Van de Ven et al., 2009; Lange and Crusius, 2015a,b). Previous research on envy was more focused on material inequalities (Carter and Gilovich, 2010; Fiske, 2011; Lin and Utz, 2015; Lin et al., 2018); the present research aimed to investigate the subjective facet of social status as well, taking into account the role of deservingness. Our findings suggest that SSS intensifies feelings of envy more than OSS and that deservingness helps differentiate between benign and malicious envy. A potential explanation for the prominent role of SSS in envy is that social factors are more related to our identity and cause more frustration, which can result in envy (Salovey and Rodin, 1984; DeSteno and Salovey, 1996; Lin et al., 2018). It has to be noted that previous studies (Salovey and Rodin, 1984; DeSteno and Salovey, 1996) confirmed this relationship in the case of jealousy, although recent research gave empirical evidence for the role of self-relevance in the case of envy as well (Lin et al., 2018). Although envy and jealousy have some overlap regarding hostility, lowered self-esteem, and sadness, they are two distinct emotions (Parrott and Smith, 1993). Envy is more focused on inferiority and therefore can be characterized by self-diminishment and resentment, while jealousy is more focused on the threat of loss of another’s fidelity and can be characterized by anxiety, distrust, and anger (Parrott and Smith, 1993).

There are two contradicting theories regarding the role of material things in envy. Some scholars suggest that, as material possessions are easily comparable, individuals compare themselves more frequently in this domain, and that consequently envy is experienced more in relation to material possessions (Carter and Gilovich, 2010). In contrast, others suggest that envy is most intense when social comparison is important for a person’s identity (Salovey and Rodin, 1984; Bolló et al., 2018).

Furthermore, although previous studies indicated that individuals tend to exaggerate the importance of OSS in hypothetical situations (Bolló et al., 2018), this study did not confirm this finding. In Study 2 respondents were asked to evaluate their feelings in a hypothetical situation, but SSS still played a more prominent role. However, in Study 2 respondents were asked to imagine that they were in the role of the envier, while in previous studies they were either the envied one (Lin et al., 2018) or the comparison affected their own status (Bolló et al., 2018). The findings of this study therefore suggest that there is a discrepancy between what individuals believe others are envious of and what they themselves are envious of, which can be a direction for future research.

Furthermore, the present research study replicated previous findings about the role of deservingness in envy (Parrott and Smith, 1993; Lange and Crusius, 2015b; Crusius and Lange, 2017; Crusius et al., 2017). Benign envy was more likely to be expressed when the superior other’s outcome was deserved and malicious envy was more likely when it was seen to be (Study 1) or characterized as (Study 2) undeserved. In the present research we applied the value theory of deservingness by Feather (1992). By definition, deservingness refers to whether the outcome is contingent with the situation: if there is a fit between the situation and the outcome it is deserved, otherwise it is undeserved (Feather, 1999). Based on Feather (1992), in Study 2 we characterized deserved advantage by positively valued behaviors (hard work in the case of OSS and being dependable in the case of SSS) and undeserved advantage by a negatively valued behavior (“cozying up” to others) and both were followed by the same positive outcome. In the present study, attributing the superior other’s success as undeserved (negatively valued behavior followed by a positive outcome) promoted malicious envy, while attributing the other’s advantage as deserved (positively valued behavior followed by a positive outcome) promoted benign envy. According to attribution theory (Hareli and Weiner, 2002), balanced structures (Heider, 1958) carry the possibility of controllability (namely that hard work pays off) and individuals will have the motivation to work hard and become as successful as the superior other.

In summary, the findings indicate that SSS and OSS play different roles in the generation of envy. SSS is more relevant in upward social comparisons leading to benign and malicious envy, and material possessions do not motivate people to move up the social hierarchy to the same extent.

Limitations and Future Studies

Although this study has important implications in relation to envy, there are a number of limitations which should be taken into account. Firstly, females were over-represented in the sample, which may lead to biased results. Previous studies suggest that women are more likely to avoid socially comparative situations that men (Niederle and Vesterlund, 2007; Rand, 2017), which can have an effect on envy.

Secondly, both studies were cross-sectional and no behavioral measures were used. Future studies should apply longitudinal or experimental design with behavioral measures.

Thirdly, Study 2 was a situation evaluation task with an imaginary scenario, so participants’ reactions in this imaginary situation may differ from their reactions in a real-life scenario. Although applying a vignette method in Study 2 can lead to interesting and informative contributions, there are limitations, especially for examining potentially less desirable emotions like envy (Van Dijk et al., 2006). For example, in the undeserved conditions of Study 2 participants might draw negative evaluations of not only the outcome but also the person themselves and it might also affect their answer about envy, added to “deservedness,” as Crusius and Lange (2014) pointed out previously that malicious envy biases attention toward the envied person rather than the advantage of this person. In future studies, this bias can be treated with manipulating not only the deservingness of the outcome but also the characteristics of the person, and then investigating their interactions.

However, vignette studies have long been used in experimental emotion research, offering the possibility to systematically control for other factors by providing identical information to respondents, thereby increasing their internal validity (Powell et al., 2008). In addition, there is empirical evidence that vignette studies can be highly generalizable to real life behavior, while overcoming the ethical, practical, and scientific limitations associated with alternative methods (Evans et al., 2015). Furthermore, respondents were assured about their anonymity and were encouraged to answer honestly. In sum, despite the limitations of online hypothetical methods, they are widely used in envy research (for example, Parrott and Smith, 1993; Lange and Crusius, 2015b; Poelker et al., 2019) and there is also empirical evidence that people do not seem more reluctant to report envy than other negative social emotions (Hareli and Weiner, 2002).

There are several potential directions for future studies, but the most important is that more emphasis should be placed on social factors instead of material inequalities in envy research. SSS is a broad conception but investigating its elements, such as respect or influence, could be a fruitful area. Furthermore, future studies should investigate possible mediating variables between envy and social status. Some possible mediators may be status maintenance strategies, prestige, and dominance. Previous research indicates that prestige is related to SSS (Bolló et al., 2018) and benign envy (Crusius and Lange, 2017).

Losing Elections' Effects on Political and Social Attitudes and Subjective Well-being: Most effects are bigger for those with strong partisan attachments, some are bigger for men

Toshkov, Dimiter, and Honorata Mazepus. 2020. “Winning and Losing Democratic Elections: Effects on Political and Social Attitudes and Subjective Well-being.” OSF Preprints. December 14. doi:10.31219/osf.io/j9dty

Abstract: In democracies, losing free and fair elections is a normal part of politics, and the consent of losers is needed for the survival of democratic government itself. But being on the losing side of the electoral contest can trigger important changes in the political and social attitudes, and even in the life outlook and subjective well-being of citizens. Based on individual-level survey data from 25 European countries and two time periods (2012 and 2018), we show that there is a significant gap between people who have voted for the parties in government and the losers of democratic elections when it comes to a wide set of political attitudes, including political trust, perceived efficacy and importance of government responsiveness and perceptions about how politics and government work. We also find that the gap between winners and losers extends to social trust, country attachment, feeling happy, healthy, safe, and optimistic, life satisfaction and perceived place in society. Most of these effects are greater in new democracies and for citizens with strong partisan attachments, some are bigger for men, and many are mediated by satisfaction with the government. Losing elections is hard for politics, but it could also be hard for the soul.

For people with an unrestricted sociosexual orientation (i.e., interested in a short-term, sexual relationship), however, self-control was related to lower selectivity...

The role of self-control and sociosexual orientation in partner selection: A speed-dating study. Tila M. Pronk et al. Journal of Social and Personal Relationships, December 9, 2020. https://doi.org/10.1177/0265407520977675

Abstract: Self-control is a crucial factor in maintaining an established romantic relationship, but its role in relationship formation is understudied. The current study tested whether trait self-control is related to a more selective approach toward romantic partners. Over 4 years, we organized 11 speed-date events at which a total of 342 single, heterosexual participants met potential partners. Our results indicated that there was no main effect of self-control on selectivity. However, there was an interaction between self-control and sociosexual orientation (SOI) in predicting selectivity. Specifically, self-control was positively related to selectivity for people with a restricted SOI (i.e., interested in a long-term, stable relationship). For people with an unrestricted SOI (i.e., interested in a short-term, sexual relationship), however, self-control was related to lower selectivity. Our findings point to the flexibility of self-control in facilitating goal progress, stimulating people to refrain from—or act on—their impulses, depending on their own personal mating goals.

Keywords: Human mate selection, interpersonal attraction, mating strategies, romantic relationships, self-control, sociosexual orientation, speed-dating

 

I thought this was already debunked, but these authors say that higher-class individuals made more errors than lower-class individuals in the Director Task (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

Is Touch in Romantic Relationships Universally Beneficial for Psychological Well-Being? The Role of Attachment Avoidance

Is Touch in Romantic Relationships Universally Beneficial for Psychological Well-Being? The Role of Attachment Avoidance. Anik Debrot et al. Personality and Social Psychology Bulletin, December 7, 2020. https://doi.org/10.1177/0146167220977709

Abstract: Affectionate touch is crucial for well-being. However, attachment avoidance is associated with negative attitudes toward touch. We tested two preregistered hypotheses about how attachment avoidance influences the association between touch in romantic couples and psychological well-being. We examined whether greater attachment avoidance is associated with a reduced link between touch and well-being, and/or whether reduced touch mediates the relationship between attachment avoidance and lower well-being. Across three studies, including two dyadic ones, we measured retrospective self-reports (Studies 1 and 2), laboratory observations (Study 2), and daily experiences (Study 3) of touch. Touch and well-being were positively associated, and attachment avoidance was associated with lower well-being and less frequent touch. Touch was associated with greater well-being regardless of level of attachment avoidance, and less frequent touch mediated the negative association between attachment avoidance and well-being in most analyses. This underscores the importance of touch, even for those valuing distance and autonomy.

Keywords: touch, attachment, well-being, attachment avoidance

No Detectable Electroencephalographic Activity 24-hours After Clinical Declaration of Death among Tibetan Buddhist Meditators in apparent tukdam, a putative postmortem meditation state

No Detectable Electroencephalographic Activity 24-hours After Clinical Declaration of Death among Tibetan Buddhist Meditators in apparent tukdam, a putative postmortem meditation state. Dylan T. Lott1 et al. Front. Psychol., Dec 2020. doi: 10.3389/fpsyg.2020.599190

Abstract: Recent EEG studies on the early postmortem interval that suggest the persistence of electrophysiological coherence and connectivity in the brain of animals and humans reinforce the need for further investigation of the relationship between the brain’s activity and the dying process. Neuroscience is now in a position to empirically evaluate the extended process of dying and more specifically, to investigate the possibility of brain activity following the cessation of cardiac and respiratory function. Under the direction of the Center for Healthy Minds at the University of Wisconsin-Madison, research was conducted in India on a postmortem meditative state cultivated by some Tibetan Buddhist practitioners in which decomposition is putatively delayed. For all healthy baseline (HB) and post-mortem (PM) subjects presented here, we collected resting state electroencephalographic data, Mismatch Negativity (MMN), and Auditory Brainstem Response (ABR). In this study, we demonstrate the feasibility that a sparse electrode EEG configuration is capable of capturing well-defined ERP waveforms from living subjects under very challenging field conditions. While living subjects displayed well-defined MMN and ABR responses, no recognizable EEG waveforms were discernable in any of these tukdam cases.

Keywords: Meditation, Tibetan Buddhism, auditory brainstem response, mismatch negativity, EEG, postmortem, Brain Death

Genetic predispositions may make some children more likely to start musical training early; they may be encouraged by other people who recognize their talent

Why Is an Early Start of Training Related to Musical Skills in Adulthood? A Genetically Informative Study. Laura W. Wesseldijk, Miriam A. Mosing, Fredrik Ullén. Psychological Science, December 14, 2020. https://doi.org/10.1177/0956797620959014

Abstract: Experts in domains such as music or sports often start training early. It has been suggested that this may reflect a sensitive period in childhood for skill acquisition. However, it could be that familial factors (e.g., genetics) contribute to the association. Here, we examined the effect of age of onset of musical training on musical aptitude and achievement in professional musicians (n = 310) and twins (n = 7,786). In line with previous literature, results showed that an earlier age of onset was associated with higher aptitude and achievement in both samples. After we adjusted for lifetime practice hours, age of onset was associated only with aptitude (p < .001; achievement: p > .14). Twin analyses showed that the association with aptitude was fully explained by familial factors. Thus, these findings provide little support for a sensitive period for music but highlight that familiar factors play an important role for associations between age of onset of training and skills in adulthood.

Keywords: sensitive period, musical training, musical expertise, twins, professional musicians

Discussion

Here, we examined whether musical training at a younger age leads to higher levels of musical expertise when controlling for the effects of total practice and familial factors, as would be predicted from the hypothesis that there is a sensitive period for musical training in childhood. In both professional musicians and twins, an earlier age of onset of musical training was associated with higher aptitude and achievement. However, when we controlled for lifetime practice, associations between age of onset and achievement became insignificant, whereas age of onset still predicted aptitude. The latter association disappeared, in turn, when we controlled for familial liability in a cotwin control design. Further twin analyses showed that the associations between age of onset of musical training and musical aptitude and between age of onset and musical achievement were fully explained by familial factors (i.e., shared genetic and shared environmental factors), in line with our cotwin control findings.

In both samples, an earlier age of onset of musical training was associated with higher musical aptitude and musical achievement, but when analyses controlled for lifetime practice, age of onset significantly predicted only higher levels of musical aptitude. Whereas this highlights the importance of adjusting for lifetime practice when exploring the above associations, it also lends further support to the findings of associations between age of onset of musical training and performance on some musical tasks reported in earlier studies (Bailey & Penhune, 2010, 2012, 2013; Bailey et al., 2014; Ireland et al., 2019; Skoe & Kraus, 2013; Steele et al., 2013; Vaquero et al., 2016; Watanabe et al., 2007). The consistency across our two samples, a professional-musician and population-based twin sample, strengthens these findings and suggests a similar effect of age of onset of musical training in a wide range of musical expertise. More importantly, our findings suggest a mediating effect of total practice on the relationship between age of onset of musical training and musical achievement but not on musical aptitude. Importantly, cumulative lifetime practice has been shown to be influenced by genetic factors (Mosing et al., 2014) and therefore does not reflect only unique environmental influences. Further, in both samples, age of onset of musical training significantly predicted higher levels of pitch discrimination but not rhythm discrimination. Only in the population-based sample did an earlier age of onset predict higher levels of melody discrimination. This is in line with the finding by Ireland and colleagues (2019) that children who received musical training before the age of 7 years outperformed children who started later on simple melody discrimination but not complex rhythm synchronization. Last, when we treated age of onset as a binary variable to test for an age window of below and at or above 8 years old, our findings remained the same.

The twin sample allowed us to extend our analyses to control for familial confounding, thereby further investigating causality, as well as to estimate the influence of genetic, shared environmental, and nonshared environmental factors on age of onset of musical training and its relationship with expertise. The twin analyses provided no evidence for a causal effect of early training in such associations. First, we found the association between age of onset of musical training (continuous or binary) and musical aptitude or achievement to diminish (close to zero) when controlling for familial liability. Further, the associations were fully explained by familial factors (i.e., common genetic and shared environmental). Because unique environmental factors did not play a role in the association between age of onset of musical training and musical expertise, the data provide little support for a causal association. We wish to emphasize that these findings do not necessarily rule out the existence of a sensitive period. Importantly, however, our findings provide clear evidence for the importance of shared familiar factors in associations between age of onset and adult performance.

As mentioned before, genetic predispositions may make some children more likely to start musical training early. They may be encouraged by other people who recognize their talent and may to a higher degree seek out, show interest in, and have access to a musical environment. More musical parents may not only pass their genetic predisposition to their children but also provide both access to early musical training and a musically enriched childhood environment that enhances musical expertise. This is an example of gene–environment correlation, in which genetics and shared environmental factors may influence the association between age of onset of musical training and later expertise. For future research, children-of-twins and adoption studies are genetically informative designs that offer possibilities to further explore gene–environment correlation.

There are some limitations of this study. First, age of onset of musical training was self-reported, which may introduce a rater or recall bias. Another possibility is that parents who are aware that their children are monozygotic twins treat them more similarly compared with parents of dizygotic twins with regard to early musical training. This would mean a violation of the equal-environment assumption (i.e., that, on average, both monozygotic and dizygotic twins are treated equally similarly), also causing an upward bias in the heritability estimates. Although we were not able to control for this in our study, multiple earlier studies have shown that the assumption generally holds (Derks, Dolan, & Boomsma, 2006). The absence of an effect of age of onset of musical training on rhythm discrimination in professional musicians should be interpreted with caution because strong ceiling effects were found in the musician sample on this subtest. Last, we note that the mean age of onset is significantly higher in male than in female participants. However, additional regression analyses separately for sex did not change the findings. One major strength of this study is the availability of both a professional musician sample and a large population-based twin sample. This allowed us to fully explore the association between age of onset of musical training and musical expertise while controlling for confounds between genetic and shared environmental factors.

The present study is, to our knowledge, the largest and only genetically informative study to focus on whether starting musical training at a younger age leads to higher levels of musical expertise. When controlling for lifetime practice, we found that an earlier age of onset of musical training predicted higher levels of musical aptitude in adulthood in professional musicians and in the general population. However, the association diminished when analyses controlled for familial liability in a cotwin control design. This, together with the finding that the association between age of onset of musical training and musical aptitude was fully explained by familial factors, suggests that a genetic predisposition for music may make children start musical training at a younger age. Thus, our findings provide little direct support that early training has a specific, causal effect on later performance and achievement; rather, they highlight the importance of taking into account cumulative measures of practice as well as genetic and shared environmental factors when studying sensitive periods and effects of an early age of onset of musical training on expertise in later life.

Some participants described sexual boredom as feeling obligated to engage in undesired sexual acts

Perceptions of sexual boredom in a community sample. Leonor de Oliveira,Joana Carvalho & Pedro Nobre. Journal of Sex & Marital Therapy, Dec 8 2020. https://doi.org/10.1080/0092623X.2020.1854405

Abstract: This study explored the definitions of sexual boredom in a large community sample of Portuguese individuals. A thematic analysis of written responses to the question “What is sexual boredom for you?” was conducted with 653 participants aged 18 to 75 (M = 33.14; SD = 9.01) of multiple genders, sexual orientations, and relationship types. Three main themes were identified: definitions of sexual boredom, predisposing and maintenance factors of sexual boredom, and managing of sexual boredom. Sexual monotony, sexual desire, and hedonic value stand out as defining features of sexual boredom. Findings suggest the need of a multidimensional measure of sexual boredom.

Discussion

This thematic analysis identified diverse definitions of sexual boredom, as well as individual,

interpersonal, and practice-related factors involved, and, finally, management paths.

Participants frequently defined sexual boredom with aspects of sexual monotony, lack of sexual

desire and lack of hedonic value. Monotony is a core feature of general boredom (Fenichel, 1951;

Geiwitz, 1966; Perkins & Hill, 1985; Zuckerman, 1979) and research verified that monotonous

stimuli led to decreases in judged hedonic value (Berlyne, 1970). Sexual monotony is central to

the definition of sexual boredom (Watt & Ewing, 1996), which was negatively correlated with sexual

satisfaction and sexual desire (Carvalheira et al., 2014;
Stulhofer et al., 2010).

Some participants described sexual boredom as feeling obligated to engage in undesired sexual

acts. We are unaware of similar findings in previous research. In the context of general boredom,

research concluded that boredom is a function of the level of effort required to attend to stimuli

that are not intrinsically captivating (Leary et al., 1986; Mikulas & Vodanovich, 1993). Being

bored with an obligation in a more mundane situation may not cause much distress, however

this might not be the case for mandatory sex.

In addition, participants identified sexual boredom could be a result of having sex with the

same partner. These findings may be partially explained by the sexual strategies theory (Buss &

Schmitt, 1993) that postulates sexual boredom in males restores mating behavior in the presence

of novel females (see Dewsbury, 1981). According to this view, desire for sexual variety is not

observed in women (Buss & Schmitt, 1993; Schmitt et al., 2001), but our study suggests sexual

boredom linked to having sex with the same partner is too found in women. Possibly, some

people, independently of gender, may have a non-monogamous orientation, which may be in the

genesis of their sexual boredom.

Our findings suggest sex frequency may also play a role in one’s assessment of sexual boredom.

Although no previous research addressed sexual boredom and sex frequency, some studies

reported sex frequency predicts sexual satisfaction in couples (e.g. Frederick et al., 2017; McNulty

et al., 2016; Schoenfeld et al., 2017). Further research is needed to determine if low sex frequency

can trigger or result in sexual boredom.

Finally, our research implies having low or no emotional connection with a sexual partner

may contribute to sexual boredom for some. There are no previous studies addressing this link,

although emotional connection to a sexual partner was found as an important component of

sexuality in long-term couples (Lemieux et al., 2004), friends with benefits (Lehmiller et al.,

2011), and individuals reporting having “great sex” (Kleinplatz & Menard, 2007).

Our findings highlight potential cognitive, emotional, and physical mechanisms of sexual boredom,

namely distraction, negative affect, and fatigue – all of which were previously related with

boredom proneness (Farmer & Sundberg, 1986; Malkovsky et al., 2012; Mercer-Lynn et al., 2014),

or with decreases in sexual desire (Maserejian et al., 2010; Murray et al., 2014). However, there is

no research on individual factors of sexual boredom we are aware of. This study indicates that

similarly to general boredom, sexual boredom may have relationships with attentional processes,

affect, and physical well-being. More importantly, it suggests sexual boredom is linked to personal

distress, emphasizing the need of further examining this construct as a sexual problem with

impact on sexual relationships.

In addition, our participants linked partner and relationship factors to sexual boredom.

Although we did not find research concerning partner factors in sexual boredom, some studies

indicate partners’ poor sexual skills impacted negatively sexual desire in women (Basson, 2001;

Brotto et al., 2011; Gehring, 2003), whilst partner responsiveness was positively associated with

sexual satisfaction in women and men (Vaillancourt-Morel et al., 2019). Within relationship factors,

were identified themes of lack of passion or eroticism, relationship issues, and duration of

relationship - which were previously related with decreases in sexual desire (Klusmann, 2002;

Murray et al., 2014; Murray & Milhausen, 2012; Sims & Meana, 2010). Only the studies of

Tunariu and Reavey (2003, 2007) explored relational aspects of sexual boredom, suggesting poor

sexual communication and relationship length could lead to sexual boredom.

Engaging in solitary practices and lack of sexual stimulation during partnered activity were

two reasons our participants related to sexual boredom. We know masturbation was related with

boredom (Gana et al., 2001), and sexual boredom (Carvalheira et al., 2015), but there seem to be

no studies regarding partnered sexual practices and sexual boredom. Moreover, several participants

reflected on a general sense of frustration stemming from sexual disappointment, as when

sex does not meet expectation. This could be in part related to the over-emphasis placed on sexual

variety and novelty (Tunariu & Reavey, 2007), which sets unrealistic expectations, and consequently

leads to frustration (Metz & McCarthy, 2011).

Several participants referred potential stages involved in managing sexual boredom. Some

mentioned acknowledging changing sex patterns allowed them identifying sexual boredom, while

others reflected on solutions to overcoming this, or identified potential constraints doing so.

Participants in this study named engaging in novel sexual behaviors (e.g. try new positions,

using sex toys, practicing BDSM, etc.) as potential solutions for overcoming sexual boredom.

Previous research suggested introducing sexual novelty to combat negative consequences of sexual

boredom could be helpful for couples in long-term monogamous relationships (Matthews

et al., 2018).

From the participants’ answers we also extracted some potential constraints, which may possibly

interfere with adopting new practices to fight sexual boredom, namely sexual beliefs and

ignorance of sexuality or one’s body. Research shows dysfunctional sexual beliefs play a role in

sexual dysfunction (Nobre & Pinto-Gouveia, 2006), and specifically in sexual desire in men and

women (Carvalho & Nobre, 2010, 2011). As well, poor sexual skills, such as unwillingness to integrate

the sexual skills necessary to uphold exciting sex, was postulated by Tunariu and Reavey

(2007) as a factor leading to the onset of sexual boredom. Our study adds evidence for the

importance of sexual education in managing sexual problems, an area of clinical intervention

with people with sexual difficulties for some time (Annon, 1976).

Limitations

This study aimed to explore definitions and dimensions of sexual boredom in a heterogeneous

sample of the community. Like many studies of sexuality, participants volunteering to take part

in the investigation may not resemble the general population in several aspects, especially in what

concerns openness to discuss sex related matters. Although our findings are not meant for generalization,

it is possible that they more closely reflect women’s sexual boredom, as they made up

most of our sample. In addition, the investigators responsible for the analysis were both women

psychologists, which may have also influenced the process. Another drawback of this study relates

to the potential influence of survey content on our participants’ answers to the open-ended item.

We are mindful that the participants’ attitudes and responses may have been primed having

answered questionnaires on some aspects of human sexuality before providing their definitions of

sexual boredom. This study did not assess intercoder reliability as, similarly to Braun and Clarke

(2019), we believe this would bear a positivist assumption there is a reality in the data that can

be accurately captured through coding. Our final coding matrix is purposely a simplification of a

complex construct and a product of these authors’ choices. While acknowledging this we also

stress the importance of rendering dimensions of sexual boredom intelligible, as most of the individual

and interpersonal aspects of sexual boredom were not yet known.

Maybe our visual cortex has, beyond the 2 posited pathways (one computes the identity of an object, the other the location), a 3d one for moving faces & bodies (expressions, eye-gaze, audio-visual integration, intention, mood)

Evidence for a Third Visual Pathway Specialized for Social Perception. David Pitcher, Leslie G. Ungerleider. Trends in Cognitive Sciences, December 14 2020. https://doi.org/10.1016/j.tics.2020.11.006

Rolf Degen's take: https://twitter.com/DegenRolf/status/1338460280641220610

Highlights

* The two-visual pathway model of primate visual cortex needs to be updated. We propose the existence of a third visual pathway on the lateral brain surface that is anatomically segregated from the dorsal and ventral pathways.

* The third pathway exists in human and non-human primates. In humans, the third pathway projects from early visual cortex into the superior temporal sulcus (STS). In macaques the third pathway projects from early visual cortex into the dorsal bank and fundus of the STS.

* The third pathway has distinct functional properties. It selectively responds to moving faces and bodies. Visual field-mapping studies show that the third pathway responds to faces across the visual field to a greater extent than the ventral pathway.

* The third pathway computes a range of higher sociocognitive functions based on dynamic social cues. These include facial expression recognition, eye gaze discrimination, the audiovisual integration of speech, and interpreting the actions and behaviors of other biological organisms.

Abstract: Existing models propose that primate visual cortex is divided into two functionally distinct pathways. The ventral pathway computes the identity of an object; the dorsal pathway computes the location of an object, and the actions related to that object. Despite remaining influential, the two visual pathways model requires revision. Both human and non-human primate studies reveal the existence of a third visual pathway on the lateral brain surface. This third pathway projects from early visual cortex, via motion-selective areas, into the superior temporal sulcus (STS). Studies demonstrating that the STS computes the actions of moving faces and bodies (e.g., expressions, eye-gaze, audio-visual integration, intention, and mood) show that the third visual pathway is specialized for the dynamic aspects of social perception.

Keywords: superior temporal sulcus (STS)V5/MTneuroanatomyface perceptionbody perceptionsocial perception

For the first time in history, neuroscience is beginning to shed light on this long-held mystery of why ental imagery & perception look and feel so different

Why do imagery and perception look and feel so different? Roger Koenig-Robert and Joel Pearson. Philosophical Transactions of the Royal Society B: Biological Sciences. December 14 2020. https://doi.org/10.1098/rstb.2019.0703

Abstract: Despite the past few decades of research providing convincing evidence of the similarities in function and neural mechanisms between imagery and perception, for most of us, the experience of the two are undeniably different, why? Here, we review and discuss the differences between imagery and perception and the possible underlying causes of these differences, from function to neural mechanisms. Specifically, we discuss the directional flow of information (top-down versus bottom-up), the differences in targeted cortical layers in primary visual cortex and possible different neural mechanisms of modulation versus excitation. For the first time in history, neuroscience is beginning to shed light on this long-held mystery of why imagery and perception look and feel so different.

The popular Paul Ekman hypothesis of facial micro-expressions as indicators of lies has no scientific support

Research on Non-verbal Signs of Lies and Deceit: A Blind Alley. Tim Brennen and Svein Magnussen. Front. Psychol., December 14 2020. https://doi.org/10.3389/fpsyg.2020.613410

Introduction

Research on the detection of lies and deceit has a prominent place in the field of psychology and law with a substantial research literature published in this field of inquiry during the last five to six decades (Vrij, 2000, 2008; Vrij et al., 2019). There are good reasons for this interest in lie detection. We are all everyday liars, some of us more prolific than others, we lie in personal and professional relationships (Serota et al., 2010; Halevy et al., 2014; Serota and Levine, 2015; Verigin et al., 2019), and lying in public by politicians and other public figures has a long and continuing history (Peters, 2015). However, despite the personal problems that serious everyday lies may cause and the human tragedies political lies may cause, it is lying in court that appears to have been the principal initial motivation for the scientific interest in lie detection.

Lying in court is a threat to fair trials and the rule of law. Lying witnesses may lead to the exoneration of guilty persons or to the conviction of innocent ones. In the US it is well-documented that innocent people have been convicted because witnesses were lying in court (Garrett, 2010, 2011; www.innocenceproject.com). In evaluating the reliability and the truthfulness of a testimony, the court considers other evidence presented to the court, the known facts about the case and the testimonies by other witnesses. Inconsistency with the physical evidence or the testimonies of other witnesses might indicate that the witness is untruthful, or it may simply reflect the fact that the witness has observed, interpreted, and later remembered the critical events incorrectly—normal human errors all too well known in the eyewitness literature (Loftus, 2005; Wells and Loftus, 2013; Howe and Knott, 2015).

When the facts of the case are not well known, witness testimonies, including the testimony from alleged victims, may be critical to a verdict, and these testimonies are sometimes from witnesses who hold a personal stake in the case and shun self-incriminating statements. In many countries, a witness lying in court risks being charged with perjury—the accused typically does not risk such a reaction—but there are still cases where witnesses lie. In such cases, when there is a possibility that one or more of the witnesses are lying and the court's verdict depends upon the perceived credibility of the witnesses, the issue arises of distinguishing between lying and truthful witnesses. Is it possible to identify liars vs. truth tellers based on the non-verbal signals transmitted by the sender?

Discussion

What options does this research field now have? Does one carry on looking for reliable non-verbal cues? Does one concentrate on whether combinations of them are diagnostic of lying? Vrij et al. (2019) suggest that there are grounds for optimism, for instance, by better defining the terms, or by improving measurement of the non-verbal cues. Luke (2019) recommends increasing the power of studies by increasing sample size. We are doubtful that such strategies will be able to provide solace, because they will be unwieldy in the forensic context. To illustrate this, let us consider two phenomena: Vrij et al. (2015) reported that spontaneous saccadic eye movements (a measure related to the widely-believed-but-not-empirically-supported gaze aversion cue) distinguish between truth-tellers and liars, and Mann et al. (2012) reported that if one measures “deliberate eye contact” rather than eye contact per se, liars have longer eye contact than truth-tellers. The reason for our skepticism regarding the application of such effects is that it is difficult to apply small (albeit significant) effects to specific instances. With such cues it will generally not be possible to say who is telling the truth at an individual level, or indeed at the level of an individual statement. One could measure the spontaneous saccades of key witnesses or the amount of deliberate eye contact maintained by a witness giving their statement but it is not clear either that such measures are sufficiently reliable, or what the baseline condition should be, against which one would compare the collected data in order to declare the statement a lie or not. Is the research in a blind alley? We believe it is, as far as lie detection in the forensic context is concerned. The idea that governs the research, that there are reliable non-verbal signs to lies and deceit is itself an expression of the western psychological folklore—as pointed out by Nortje and Tredoux (2019), the theoretical foundations for the putative non-verbal cues are shaky—and few researchers in the field appear to have fully digested the possibility that the basic premise of their inquiry may be false. For complex intellectual behaviors it has long been realized that there is a number of broad factors that contribute to individual differences—genetics, cultural influences, personal experiences, and situational factors (Engel, 1977, 1980). To complicate matters, a meta-analysis by Bond and De Paulo (2008) showed that participants' truth judgments depended on the sender rather than on the person doing the judging. The effect of sender on veracity judgments has been confirmed in a number of subsequent studies: Some of us appear more (or less) credible than others, independent of whether we are telling the truth or are lying (Porter et al., 2010; Levine et al., 2011; Korva et al., 2013). In addition, the existence of the literature on cultural differences in lie detection, e.g., Castillo and Mallard (2012), would seem to undermine the idea that lies and deceit are in any useful, systematic manner related to behavior on an individual culture-free basis. We may have been looking for a lawfulness in human behavior that exists only in our minds.

Is the rational course simply to drop this line of research? We believe it is. The creative studies carried out during the last few decades have been important in showing that psychological folklore, the ideas we share about behavioral signals of lies and deceit are not correct. This debunking function of science is extremely important. But we have now sufficient evidence that there are no specific non-verbal behavioral signals that accompany lying or deceitful behavior. We can safely recommend that courts disregard such behavioral signals when appraising the credibility of victims, witnesses, and suspected offenders. For psychology and law researchers it may be time to move on.

Rolf Degen summarizing... Women who interpreted their significant other's pornography use more favorably reported higher sexual and relationship satisfaction

A Mixed-Method Analysis of Women’s Attributions about Their Partner’s Pornography Use. Uzma S. Rehman et al. The Journal of Sex Research, Dec 12 2020. https://doi.org/10.1080/00224499.2020.1856765

Rolf Degen's take: https://twitter.com/DegenRolf/status/1338075756774248448

Abstract: We used a mixed-method design to examine the attributions women in mixed-gender/sex relationships make for their partner’s perceived pornography use and whether such attributions covary with women’s relationship and sexual satisfaction. A final sample of 199 women completed measures of relationship satisfaction, sexual satisfaction, and their perceptions of partner’s pornography use. Participants also completed three open-ended questions assessing their attributions of their partner’s perceived pornography use. Qualitative analyses revealed 11 themes in women’s attributions of their partner’s perceived pornography use; some of the themes reflected on women themselves (e.g., being open-minded and accepting), whereas other themes reflected on the partner (e.g., partner is sexually bored) or the relationship (e.g., strong and trusting relationship). Furthermore, the women made positive, negative, and neutral attributions. Quantitative analyses showed that positive attributions were significantly more frequent than neutral or negative attributions and the latter two categories did not differ significantly from each other. Also, greater frequency of positive and neutral attributions and lower frequency of negative attributions were associated with higher relationship satisfaction and sexual satisfaction. Our results suggest that women make a range of attributions about their partner’s pornography use and that this variation relates meaningfully to indices of relationship functioning.

We find no evidence that female, minority and low in implicit-bias (thru an IB test) engineers exhibit lower bias or discrimination in their code; but there can be performance improvements through demographic mixing

Cowgill, Bo and Dell'Acqua, Fabrizio and Deng, Sam and Hsu, Daniel and Verma, Nakul and Chaintreau, Augustin, Biased Programmers? Or Biased Data? A Field Experiment in Operationalizing AI Ethics (June 1, 2020). In Proceedings of the 21st ACM Conference on Economics and Computation (pp. 679-681), Columbia Business School Research Paper Forthcoming, SSRN: http://dx.doi.org/10.2139/ssrn.3615404

Abstract: Why do biased predictions arise about human capital? What interventions can prevent them? We evaluate 8.2 million algorithmic predictions of math skill from ~400 AI engineers, each of whom developed an algorithm under a randomly assigned experimental condition. Our treatment arms modified programmers' incentives, training data, awareness, and/or technical knowledge of AI ethics. We then assess out-of-sample predictions from their algorithms using randomized audit manipulations of algorithm inputs and ground-truth math performance for 20K subjects. We find that biased predictions are mostly caused by biased training data. However, one-third of the benefit of better training data comes through a novel economic mechanism: Engineers exert greater effort and are more responsive to incentives when given better training data. We also assess how performance varies with programmers' demographic characteristics, and their performance on a psychological test of implicit bias (IAT) concerning gender and careers. We find no evidence that female, minority and low-IAT engineers exhibit lower bias or discrimination in their code. However we do find that prediction errors are correlated within demographic groups, which creates performance improvements through cross-demographic averaging. Finally, we quantify the benefits and tradeoffs of practical managerial or policy interventions such as technical advice, simple reminders and improved incentives for decreasing algorithmic bias.