Kevin Lewis

August 11, 2020

Historically rice-farming societies have tighter social norms in China and worldwide
Thomas Talhelm & Alexander English
Proceedings of the National Academy of Sciences, forthcoming


Data recently published in PNAS mapped out regional differences in the tightness of social norms across China [R. Y. J. Chua, K. G. Huang, M. Jin, Proc. Natl. Acad. Sci. U.S.A. 116, 6720–6725 (2019)]. Norms were tighter in developed, urbanized areas and weaker in rural areas. We tested whether historical paddy rice farming has left a legacy on social norms in modern China. Premodern rice farming could plausibly create strong social norms because paddy rice relied on irrigation networks. Rice farmers coordinated their water use and kept track of each person’s labor contributions. Rice villages also established strong norms of reciprocity to cope with labor demands that were twice as high as dryland crops like wheat. In line with this theory, China’s historically rice-farming areas had tighter social norms than wheat-farming areas, even beyond differences in development and urbanization. Rice–wheat differences were just as large among people in 10 neighboring provinces (n = 3,835) along the rice–wheat border. These neighboring provinces differ sharply in rice and wheat, but little in latitude, temperature, and other potential confounding variables. Outside of China, rice farming predicted norm tightness in 32 countries around the world. Finally, people in rice-farming areas scored lower on innovative thinking, which tends to be lower in societies with tight norms. This natural test case within China might explain why East Asia — historically reliant on rice farming — has tighter social norms than the wheat-farming West.

Culture and Student Achievement: The Intertwined Roles of Patience and Risk-Taking
Eric Hanushek et al.
NBER Working Paper, July 2020


Patience and risk-taking – two cultural traits that steer intertemporal decision-making – are fundamental to human capital investment decisions. To understand how they contribute to international differences in student achievement, we combine PISA tests with the Global Preference Survey. We find that opposing effects of patience (positive) and risk-taking (negative) together account for two-thirds of the cross-country variation in student achievement. In an identification strategy addressing unobserved residence-country features, we find similar results when assigning migrant students their country-of-origin cultural traits in models with residence-country fixed effects. Associations of culture with family and school inputs suggest that both may act as channels.

Kinship intensity and the use of mental states in moral judgment across societies
Cameron Curtin et al.
Evolution and Human Behavior, forthcoming


Decades of research conducted in Western, Educated, Industrialized, Rich, & Democratic (WEIRD) societies have led many scholars to conclude that the use of mental states in moral judgment is a human cognitive universal, perhaps an adaptive strategy for selecting optimal social partners from a large pool of candidates. However, recent work from a more diverse array of societies suggests there may be important variation in how much people rely on mental states, with people in some societies judging accidental harms just as harshly as intentional ones. To explain this variation, we develop and test a novel cultural evolutionary theory proposing that the intensity of kin-based institutions will favor less attention to mental states when judging moral violations. First, to better illuminate the historical distribution of the use of intentions in moral judgment, we code and analyze anthropological observations from the Human Area Relations Files. This analysis shows that notions of strict liability — wherein the role for mental states is reduced — were common across diverse societies around the globe. Then, by expanding an existing vignette-based experimental dataset containing observations from 321 people in a diverse sample of 10 societies, we show that the intensity of a society's kin-based institutions can explain a substantial portion of the population-level variation in people's reliance on intentions in three different kinds of moral judgments. Together, these lines of evidence suggest that people's use of mental states has coevolved culturally to fit their local kin-based institutions. We suggest that although reliance on mental states has likely been a feature of moral judgment in human communities over historical and evolutionary time, the relational fluidity and weak kin ties of today's WEIRD societies position these populations' psychology at the extreme end of the global and historical spectrum.

American base‐rate neglect: It is not the math, but the context
Shali Wu & Clifton Emery
Journal of Behavioral Decision Making, forthcoming


We investigate cross‐cultural disparities in focalism bias through two studies of probability estimation. Using 60 American and 60 Chinese participants, Experiment 1 yields the standard finding that Americans manifest greater focalism bias by tending to neglect background probability base‐rates and to rely more heavily on obtained samples in estimating true probabilities, whereas Chinese participants show little tendency to ignore base‐rates. In Experiment 2, the phrasing of the probability‐estimation task is changed to bring base‐rates into the focus of the problem statement, again using a sample of 60 Americans and 60 Chinese. This allows us to test whether cross‐cultural differences result from a tendency to focus on the sample, and ignore ‘context’ (i.e., the background base‐rates), rather than simply a discrepancy in mathematical facility between the two groups. The results show far less base‐rate neglect for Americans, but essentially no change for Chinese (who always use base‐rate information, regardless of how presented). This outcome argues against the explanation that Americans are poorer Bayesians simply because they are weaker mathematicians. Implications are discussed.

Feeling bad is not always unhealthy: Culture moderates the link between negative affect and diurnal cortisol profiles
Jiyoung Park et al.
Emotion, August 2020, Pages 721–733


Prior research has demonstrated that the daily experience of negative affect is associated with increased levels of proinflammatory activity as evidenced by higher interleukin-6 among Americans but not among Japanese. This cultural difference may be driven by culturally divergent beliefs about negative affect as a source of threat to self-image versus as natural and integral to life. Here, we examined whether culture may moderate the relationship between negative affect and biological stress responses, with a focus on the hypothalamic-pituitary-adrenal (HPA) axis activity. By using culturally matched surveys of Americans (N = 761) and Japanese (N = 328), we found that negative affect was associated with a flattening of the diurnal cortisol slope among Americans after controlling for demographic variables, personality traits, sleep patterns, and health behaviors. In contrast, the association between negative affect and the HPA axis activity was negligible among Japanese. Moreover, we assessed biological health risk with biomarkers of both inflammation (interleukin-6 and C-reactive protein levels) and cardiovascular function (higher systolic blood pressure and total-to-HDL cholesterol ratio) and found that the relationship between negative affect and increased biological health risk, which was observed only among Americans, was mediated by the flattening of the diurnal cortisol rhythm. These findings suggest that cultural differences in how emotions are construed may make the experience of negative affect more or less stressful and differentially consequential for health.

Inter-sexual mate competition in three cultures
Scott Semenyna et al.
PLoS ONE, July 2020


Darwinian sexual selection theory holds that mate selection occurs inter-sexually, and mate competition occurs intra-sexually for opposite-sex partners. We demonstrate that inter-sexual mate competition can also occur among humans at appreciable rates that vary by culture. In Canada, inter-sexual mate competition was both rare and inconsequential. However, data from two disparate non-Western cultures — Samoa and the Istmo Zapotec (Oaxaca, Mexico) — show that women frequently compete with feminine same-sex attracted males to acquire and maintain masculine male mates (i.e., men). Inter-sexual mate competition most commonly involved feminine males attempting to poach women’s masculine male sexual partners. During these interactions, women and feminine males both attempted to manipulate the man who was the object of sexual competition; feminine males attempted to entice the target man, whereas women engaged in guarding and emotionally punitive behaviours. We do not anticipate that inter-sexual mate competition will be common in most species or across all cultures. However, when males and females prefer the same sexual partners, who themselves behave in a bisexual manner, then inter-sexual mate competition can ensue.

Deadly but protective: Americans’ unique perception of weapons
Stylianos Syropoulos et al.
Peace and Conflict: Journal of Peace Psychology, forthcoming


Global levels of violence are declining, yet gun violence and other instances of instrumental violence still occur. While previous research has examined motivations for owning firearms, cognition about firearms — and in particular, perceptions of weapons as affording safety or as affording danger — has remained largely unexplored. We conducted a cross-national mixed-methods investigation involving the United States and three European countries (France, Spain, and Greece). Our findings indicated that Americans perceived weapons (assault rifle, handgun, hunting rifle, combat knife) as more protective and less dangerous than their European counterparts. These differential perceptions have implications for understanding variations in worldwide rates of violence.

Out-of-partnership births in East and West Germany
Uwe Jirjahn & Cornelia Chadi
Review of Economics of the Household, September 2020, Pages 853–881


Using data from the German Socio-Economic Panel (SOEP), we show that single women in East Germany are significantly more likely to give birth to a child than single women in West Germany. This applies to both planned and unplanned births. Our analysis provides no evidence that the difference between East and West Germany can be explained by economic factors or the higher availability of child care in East Germany. This suggests that the difference in out-of-partnership births is rather driven by behavioral and cultural differences. However, these behavioral and cultural differences do not only reflect different gender role models that evolved under the former communist regime in East Germany and the democratic one in West Germany. Partly, they also reflect a long historical divide that predates the 1945 separation of Germany.

Economic predictors of differences in interview faking between countries: Economic inequality matters, not the state of economy
Cornelius König et al.
Applied Psychology, forthcoming


Many companies recruit employees from different parts of the globe, and faking behavior by potential employees is a ubiquitous phenomenon. It seems that applicants from some countries are more prone to faking compared to others, but the reasons for these differences are largely unexplored. This study relates country‐level economic variables to faking behavior in hiring processes. In a cross‐national study across 20 countries, participants (N = 3839) reported their faking behavior in their last job interview. This study used the random response technique (RRT) to ensure participants anonymity and to foster honest answers regarding faking behavior. Results indicate that general economic indicators (gross domestic product per capita [GDP] and unemployment rate) show negligible correlations with faking across the countries, whereas economic inequality is positively related to the extent of applicant faking to a substantial extent. These findings imply that people are sensitive to inequality within countries and that inequality relates to faking, because inequality might actuate other psychological processes (e.g., envy) which in turn increase the probability for unethical behavior in many forms.

Foundations of morality in Iran
Mohammad Atari, Jesse Graham & Morteza Dehghani
Evolution and Human Behavior, forthcoming


Most moral psychology research has been conducted in Western, Educated, Industrialized, Rich, and Democratic (WEIRD) societies. As such, moral judgment, as a psychological phenomenon, might be known to researchers only by its WEIRD manifestations. Here, we start with evaluating Moral Foundations Theory (MFT) using the Moral Foundations Questionnaire, and follow up by building a bottom-up model of moral values, in Iran, a non-WEIRD, Muslim-majority, understudied cultural setting. In six studies (N = 1945) we examine the structural validity of the Persian translation of the Moral Foundations Questionnaire, compare moral foundations between Iran and the US, conduct qualitative interviews regarding moral values, expand the nomological network of “Qeirat” as a culture-specific set of moral values, and investigate the pragmatic validity of “Qeirat” in Iranian culture. Our findings suggest an additional moral foundation in Iran, above and beyond the five foundations identified by MFT. Specifically, qualitative studies highlighted the role of “Qeirat” values in Iranian culture, which are comprised of guarding and protectiveness of female kin, romantic partners, broader family, and country. Significant cultural differences in moral values are argued in this work to follow from the psychological systems that, when brought to interact with particular socio-ecological environments, produce different moral structures. This evolutionarily-informed, cross-cultural, mixed-methods research sheds light on moral concerns and their cultural, demographic, and individual-difference correlates in Iran.

Neurocognitive Underpinnings of Cross-Cultural Differences in Risky Decision Making
Xing-Jie Chen, Lan Ba & Youngbin Kwak
Social Cognitive and Affective Neuroscience, June 2020, Pages 671–680


Culture permeates across human mind and behavior. Cultural influence is reported even in economic decision making, which involves basic cognitive process, once believed to be invariant across all humans. The current study investigated the neurocognitive processes underlying economic decision making in East Asians and European Americans, with an aim to understand the cross-cultural differences in the discrete mental processes of decision making. Participants performed a risky gambling task that captures the gain maximizing and loss minimizing strategies, while EEG was simultaneously collected. Event-related potentials (ERPs) associated with spontaneous emotional arousal (P2) and effortful attentional allocation (P3) were examined to determine the cultural effects on mental processes during pre-decisional and post-decisional stages. Behaviorally, Americans showed greater loss minimization than Asians. ERPs demonstrated significant cultural differences during post-decisional evaluation of outcomes, but not during pre-decisional processes. While Asians’ ERP associated with emotional arousal (P2) was strongly modulated by gains, Americans’ ERP associated with attentional allocation (P3) was strongly modulated by losses. These results suggest that Americans make conscious efforts to be self-reliant when facing financial losses, while Asians are more emotionally aroused by financial gains, which invites a refinement to the current theoretical propositions about cultural influence on decision making.


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