Folk Beliefs About Human Genetic Variation Predict Discrete Versus Continuous Racial Categorization and Evaluative Bias

What role do folk beliefs about human genetic variation play in racial categorization and evaluation? In two studies, the authors assessed or manipulated participants' estimates of the percentage of genetic material that human beings have in common and examined whether this variable would predict categorization (Study 1) and evaluation (Study 2) of faces that varied monotonically in Black–White racial composition. In both studies, participants with low (vs. high) genetic overlap beliefs implicitly perceived the boundary between races to be more discrete. These results remained significant even when controlling for such variables as Need for Cognition, political ideology, essentialist beliefs, and “entity” beliefs. These findings suggest that believing that all people possess similar (vs. different) genetic makeup may serve as a key assumption that shapes racial categorization.