Previous research has shown that Latin Americans tend to value positive emotion and favorable self-evaluation. However, it has remained unclear whether this positivity extends to a robust self-enhancement bias. In a series of studies across four Latin American countries—Chile, Mexico, Ecuador, and Colombia—we found clear evidence of such a bias. Crucially, this self-enhancement was associated not with independence (as is typically assumed in Western contexts), but with interdependence. In this respect, Latin American self-enhancement resembles patterns observed in the Middle East, diverging from the North American model despite surface similarities.

This is the first comprehensive demonstration of self-enhancement in Latin America based on multiple validated measures. Even more importantly, it challenges the long-standing Western assumption that self-enhancement is a byproduct of striving for independence. By revealing its interdependent roots in Latin American contexts, our findings suggest that self-positivity can serve communal or relational functions, not just individualistic ones. This opens a new research agenda on interdependent selfhood in Latin America and its implications for motivation, emotion, and identity.

Although cultural psychology has consistently shown that East Asians self-enhance less than European Americans, some skeptics continue to argue that East Asians may simply hide their self-positivity. According to this view, they are being modest or strategic, concealing what many (especially American) psychologists consider a universal “human instinct.” This paper draws on recent neuroscience research to challenge that skepticism, showing that the absence of self-enhancement among East Asians is not merely a matter of social presentation, but reflects culturally shaped motivational processes at the neural level.

Psychology as a discipline has long harbored a cultural bias—often assuming that traits like self-enhancement are inherently human. This assumption, historically echoed by figures like William James, continues to shape mainstream thinking. By integrating neuroscientific evidence, this paper not only challenges that bias but also opens a new window into how cultural participation shapes the neural basis of motivation. It offers a compelling demonstration of how culture penetrates even the most basic psychological mechanisms, including those related to self-evaluation.

This paper focuses on uric acid. If you’re wondering why someone studying culture should care about a chemical compound best known for its association with gout, hypertension, and similar conditions, you’re not alone. Our paper makes a somewhat heretical claim: that uric acid and humans co-evolved due to its role as a potent antioxidant, which was essential for sustaining the high energy consumption required for increasingly complex cognitive functioning in the evolution of Homo sapiens—the cultural animal. Our data show that culturally endorsed traits related to interdependence longitudinally predict an increase in the concentration of uric acid in the bloodstream among Japanese adults.

There are many conjectures about how human culture evolved. Ever since humans diverged from a common primate ancestor in Africa more than 6 million years ago, one major challenge has been to establish the metabolic basis for sustaining high-energy consumption while protecting biological systems—particularly the central nervous system (i.e., the brain)—from oxidative damage. The idea proposed here may help clarify one piece of this vast puzzle: how a single primate species evolved into what it is today—an animal with extraordinarily high cognitive power, capable of constructing the massive biological niche we call culture.