Ethnicity can be a
means by which people identify themselves and others. This type of identification mediates many kinds of social interactions and may reflect adaptations to a long history of group living in humans. Recent
admixture in the US between groups from different continents, and the historically strong emphasis on
phenotypic differences between members of these groups, presents an opportunity to examine the degree of concordance between estimates of group membership based on
genetic markers and on visually-based estimates of
facial features. We first measured the degree of Native American, European, African and East Asian
genetic admixture in a sample of 14 self-identified Hispanic individuals, chosen to cover a broad range of Native American and European
genetic admixture proportions. We showed frontal and side-view photographs of the 14 individuals to 241 subjects living in New Mexico, and asked them to estimate the degree of NA
admixture for each individual. We assess the overall concordance for each observer based on an aggregated measure of the difference between the observer and the
genetic estimates. We find that observers reach a significantly higher degree of concordance than expected
by chance, and that the degree of concordance as well as the direction of the discrepancy in estimates differs based on the ethnicity of the observer, but not on the observers' age or sex. This study highlights the potentially high degree of discordance between physical appearance and
genetic measures of ethnicity, as well as how
perceptions of ethnic affiliation are context-specific. We compare our findings to those of previous studies and discuss their implications.
