Depression, neuroticism and 2D:4D ratio: evidence from a large, representative sample

A body of literature reports higher rates of depression and neuroticism in female samples compared to male samples. Numerous studies have investigated the role of prenatal sex hormone exposure in this sex difference, using the ratio between the second and fourth digit of the hand ("2D:4D") as a putative marker. However, the sample sizes of those studies were mostly small and results remained inconclusive. The aim of the present study is to test the suggested associations between depression, neuroticism and the 2D:4D ratio in a large, representative sample of over 3,000 German individuals. It was hypothesized that a higher 2D:4D (supposedly representing a more "feminine" prenatal hormone exposure) would positively predict (1) one's history of depression as well as (2) neuroticism rates and (3) acute depressive symptom scores. Controlling for biological sex, we only found suggestive evidence for linear associations with neuroticism in the case of left hand 2D:4D ratios and the mean 2D:4D of both hands. However, additional analyses indicated that these results may have been spurious due to confounding. Our findings suggest that the 2D:4D ratio is not a relevant predictor of depression, while there was mixed evidence in the case of neuroticism

Exposure to Inequality may Cause Under-Provision of Public Goods: Experimental Evidence

Economic inequality is rising globally and due to developments in information technologies and globalization, nowadays individuals are more exposed to this inequality than ever. Recent studies show that exposure to inequality may shape economic decisions. In this article, we test whether contributions in the public goods game are sensitive to information about inequality of personal benefits between groups. Our results show that learning the return levels of another group with higher (lower) benefits decreases (increases) the contributions with a stronger reaction by low benefit groups. Our further tests show that this effect diminishes when the benefit difference between the groups gets smaller. These results suggest that exposure to inequality might have detrimental impact on public goods provision, yet this effect gets negligible as economic inequality reduces

Cognitive reflection and 2D:4D: Evidence from a large population sample

Bosch-Domènech et al. (2014) reported a negative association between 2D:4D, a suggested marker of prenatal testosterone exposure, and the Cognitive Reflection Test (CRT) in a sample of 623 university students. In this pre-registered study, we test whether we can replicate their findings in a general population sample of over 2,500 individuals from Germany. We find no statistically significant association between 2D:4D and the CRT in any of our primary hypothesis tests, or in any of our pre-registered exploratory analyses and robustness tests. The evidence is strong (based on the 99.5% confidence intervals in all three primary hypotheses tests) against effect sizes in the hypothesized direction larger than 0.075 CRT units (0.073 of the CRT standard deviation) for a one standard deviation change in 2D:4D

Gender Differences in Performance Predictions: Evidence from the Cognitive Reflection Test

This paper studies performance predictions in the 7-item Cognitive Reflection Test (CRT) and whether they differ by gender. After participants completed the CRT, they predicted their own (i), the other participants' (ii), men's (iii), and women's (iv) number of correct answers. In keeping with existing literature, men scored higher on the CRT than women and both men and women were too optimistic about their own performance. When we compare gender-specific predictions, we observe that men think they perform significantly better than other men and do so significantly more than women. The equality between women's predictions about their own performance and their female peers cannot be rejected. Our findings contribute to the growing literature on the underpinnings of behavior in economics and in psychology by uncovering gender differences in confidence about one's ability relative to same and opposite sex peers

Payment Scheme Changes and Effort Provision: The Effect of Digit Ratio

Economic experiments report that individuals perform better under a piece rate payment scheme in comparison to a fixed payment scheme. The reason is straightforward: incentives motivate people, and without incentives they decrease their effort. Yet women are prone to choose a fixed payment over a piece rate payment scheme. We aim to find out if this gender effect is related to prenatal exposure to testosterone, which by nature is sexually dimorphic and has permanent effects on human brain development with an impact on cognitive and physical skills, as well as behavior. We investigate the effect of prenatal testosterone exposure on performance adjustment in a real effort task. Each subject is salaried under either a fixed rate or piece rate payment scheme for five periods and subsequently encounters the alternative payment method for another five periods. To observe the prenatal testosterone levels that the participants were exposed to during pregnancy, we use the so-called digit ratio as an indirect measurement method. It uses the length-ratio between the participants’ index and ring fingers to infer about their in utero testosterone exposure. Our results confirm the previous findings indicating that individuals perform better when incentivized by a piece rate payment scheme. Subjects who are paid piece rate in the first half of the experiment immediately decrease their performance at the beginning of the second half when paid under a fixed payment scheme. In contrast, subjects increase their effort if the payment method is switched from fixed rate to piece rate in the second half of the experiment. Subjects who were exposed to higher levels of prenatal testosterone provide significantly lower effort when the payment scheme is switched from piece rate to fixed rate

Digit Ratio Measurement Guide

Literature on Digit Ratio is rapidly growing in Economics. Quite surprisingly we observe that there is no consensus about how to make an accurate measurement in such a delicate task. Along this brief document we offer some concise guidance of how to scan the hands using digital scanners and provide a comprehensive guideline to make a reliable measurement of the 2D:4D. Furthermore, we point out the most common imaging and measurement errors. We also provide a number of hints aimed to avoid these errors that in some cases may cause systematic inaccuracies

Income Inequality and Risk Taking

Standard economic theory assumes that individual risk taking decisions are independent from the social context. Recent experimental evidence however shows that the income of peers has a systematic impact on observed degrees of risk aversion. In particular, subjects strive for balance in the sense that they take higher risks if this gives them the chance to break even with their peers. The present paper is, to the best of our knowledge, the first systematic analysis of income inequality and risk taking. We perform a real-effort field experiment where inequality is introduced to different wage rates. After the effort phase subjects can invest (part of) their salary into a risky asset. Besides the above mentioned possibility of higher risk taking of low-wage individuals to break even with high-wage individuals, risk taking can be influenced by an income effect consistent with e.g. decreasing absolute risk aversion and a house money effect of high-wage individuals. Our results show that the dominant impact of inequality on risk taking is what can be termed a social house money effect: high-wage individuals take higher risks than low-wage individuals only if they are aware of the inequality in wages

Payment Scheme Changes and Effort Provision: The Effect of Digit Ratio

Economic experiments report that individuals perform better under a piece rate payment scheme in comparison to a fixed payment scheme. The reason is straightforward: incentives motivate people, and without incentives they decrease their effort. Yet women are prone to choose a fixed payment over a piece rate payment scheme. We aim to find out if this gender effect is related to prenatal exposure to testosterone, which by nature is sexually dimorphic and has permanent effects on human brain development with an impact on cognitive and physical skills, as well as behavior. We investigate the effect of prenatal testosterone exposure on performance adjustment in a real effort task. Each subject is salaried under either a fixed rate or piece rate payment scheme for five periods and subsequently encounters the alternative payment method for another five periods. To observe the prenatal testosterone levels that the participants were exposed to during pregnancy, we use the so-called digit ratio as an indirect measurement method. It uses the length-ratio between the participants’ index and ring fingers to infer about their in utero testosterone exposure. Our results confirm the previous findings indicating that individuals perform better when incentivized by a piece rate payment scheme. Subjects who are paid piece rate in the first half of the experiment immediately decrease their performance at the beginning of the second half when paid under a fixed payment scheme. In contrast, subjects increase their effort if the payment method is switched from fixed rate to piece rate in the second half of the experiment. Subjects who were exposed to higher levels of prenatal testosterone provide significantly lower effort when the payment scheme is switched from piece rate to fixed rate

Income Inequality and Risk Taking

Standard economic theory assumes that individual risk taking decisions are independent from the social context. Recent experimental evidence however shows that the income of peers has a systematic impact on observed degrees of risk aversion. In particular, subjects strive for balance in the sense that they take higher risks if this gives them the chance to break even with their peers. The present paper is, to the best of our knowledge, the first systematic analysis of income inequality and risk taking. We perform a real-effort field experiment where inequality is introduced to different wage rates. After the effort phase subjects can invest (part of) their salary into a risky asset. Besides the above mentioned possibility of higher risk taking of low-wage individuals to break even with high-wage individuals, risk taking can be influenced by an income effect consistent with e.g. decreasing absolute risk aversion and a house money effect of high-wage individuals. Our results show that the dominant impact of inequality on risk taking is what can be termed a social house money effect: high-wage individuals take higher risks than low-wage individuals only if they are aware of the inequality in wages