The 2D:4D ratio does not always correlate with economic behavior: A field experiment with African-Americans.

Several studies present evidence of correlations between prenatal testosterone exposure measured with the 2D:4D ratio and behaviors such as pro-social behavior, risk and patient attitudes, and self-employment. Individuals exposed prenatally to higher levels of testosterone have lower levels of risk aversion, higher levels of patience and invest more in others, and in themselves, therefore have higher individual financial wellbeing. We test these hypotheses with a sample of 115 African-Americans who live in a low-income urban area in the U.S. The 2D:4D ratio in our sample of males and females does not have a consistent and robust correlation with risk, patient attitudes, pro-social behavior and self-employment in contrast to previous studies.

Group-Level Selection Increases Cooperation in the Public Goods Game.

When groups compete for resources, some groups will be more successful than others, forcing out less successful groups. Group-level selection is the most extreme form of group competition, where the weaker group ceases to exist, becoming extinct. We implement group-level selection in a controlled laboratory experiment in order to study its impact on human cooperation. The experiment uses variations on the standard linear public goods game. Group-level selection operates through competition for survival: the least successful, lowest-earning groups become extinct, in the sense that they no longer are able to play the game. Additional control treatments include group comparison without extinction, and extinction of the least successful individuals across groups. We find that group-level extinction produces very high contributions to the provision of the public good, while group comparison alone or individual extinction fail to cause higher contributions. Our results provide stark evidence that group-level selection enhances within-group cooperation.

Economic Preferences and Obesity among a Low-Income African American Community.

Obesity has reached epidemic proportions in the US, with a significantly higher fraction of African Americans who are obese than whites. Yet there is little understanding of why some individuals become obese while others do not. We conduct a lab-in-field experiment in a low-income African American community to investigate whether risk and time preferences play a role in the tendency to become obese. We examine the relationship between incentivized measures of risk and time preferences and weight status (BMI), and find that individuals who are more tolerant of risk are more likely to have a higher BMI. This result is driven by the most risk tolerant individuals. Patience is not independently statistically related to BMI in this sample, but those who are more risk averse and patient are less likely to be obese.

Health behavior and behavioral economics: economic preferences and physical activity stages of change in a low-income African-American community.

PURPOSE: To examine the relationship between physical activity stages of change and preferences for financial risk and time. DESIGN: A cross-sectional, community-based study. SETTING: A low-income, urban, African-American neighborhood. SUBJECTS: One hundred sixty-nine adults. MEASURES: Self-reported physical activity stages of change-precontemplation to maintenance, objectively measured body mass index and waist circumference, and economic preferences for time and risk measured via incentivized economic experiments. ANALYSIS: Multivariable ordered logistic regression models were used to examine the association between physical activity stages of change and economic preferences while controlling for demographic characteristics of the individuals. RESULTS: Individuals who are more tolerant of financial risks (odds ratio [OR] = 1.31, p < .05) and whose time preferences indicate more patience (OR = 1.68, p < .01) are more likely to be in a more advanced physical activity stage (e.g., from preparation to action). The likelihood of being in the maintenance stage increases by 5.6 and 10.9 percentage points for each one-unit increase in financial risk tolerance or one-unit increase in the time preference measure, respectively. CONCLUSION: Greater tolerance of financial risk and more patient time preferences among this low-income ethnic minority population are associated with a more advanced physical activity stage. Further exploration is clearly warranted in larger and more representative samples.