‘Us/Them’ is a dichotomy used to differentiate human beings on the basis of race, gender, religion, socioeconomic status, and so forth, but it is also used to sort humans from nonhuman animals. Here, I discuss cognitive biases and mental shortcuts that characterize both discriminations. The ingroup/ outgroup bias, ruling racist positions, has is profound roots in predisposed and phylogenetically ancient abilities that enhanced early hominines’ survival chances by supporting categorization at different levels. Such abilities, along with a set of basic cognitive capacities (the so-called “core knowledge”), have been shaped by evolution, are inherited from our ancestors, and are shared with other animal species. The criteria for inclusion/exclusion in the ‘us/them’ categories can change by virtue of previous experience, and some preliminary evidence suggests that the cognitive continuum that characterizes all living species can probably lead people to understand that the differences in mental abilities between species are just a matter of degree, as Darwin correctly suggested. Whether a similar effect can apply to other biased evaluations like those based on religion and gender, thus intervening to overcome cultural racism, is a possibility that remains to be investigated in future studies.
