Historical roots of implicit bias in slavery

Significance Geographic variation in implicit bias is associated with multiple racial disparities in life outcomes. We investigated the historical roots of geographical differences in implicit bias by comparing average levels of implicit bias with the number of slaves in those areas in 1860. Counties and states more dependent on slavery in 1860 displayed higher pro-White implicit bias today among White residents and less pro-White bias among Black residents. Mediation analyses suggest that historical oppression may be transmitted into contemporary biases through structural inequalities, including disparities in poverty and upward mobility. Given the importance of contextual factors, efforts to reduce unintended discrimination might focus on modifying social environments that cue implicit biases in the minds of individuals. Implicit racial bias remains widespread, even among individuals who explicitly reject prejudice. One reason for the persistence of implicit bias may be that it is maintained through structural and historical inequalities that change slowly. We investigated the historical persistence of implicit bias by comparing modern implicit bias with the proportion of the population enslaved in those counties in 1860. Counties and states more dependent on slavery before the Civil War displayed higher levels of pro-White implicit bias today among White residents and less pro-White bias among Black residents. These associations remained significant after controlling for explicit bias. The association between slave populations and implicit bias was partially explained by measures of structural inequalities. Our results support an interpretation of implicit bias as the cognitive residue of past and present structural inequalities.