"In x Out": Reviewing the Group Bias through the Biological Perspective

The factors underlying to the ingroup favoritism and outgroup indifference/hostility are broadly studied by social psychology, where studies report that, for example, individuals trust more and associate positive words to members of the same group. The study of these factors can help in understand phenomena such as prejudice and ethonocentrism. However, a systematic search in the databases Web of Science, Google Scholar, Scielo, and Lilacs for the keywords related to group bias showed a studies shortage for this topic in Brazil. Besides, in the studies retrieved, just one fi tted into evolutionary perspective and no study has approached the neuroendocrine mechanisms of the group bias. Therefore, the objective of this study was to discuss the group bias through the biological perspective, explaining the evolutionary hypothesis to the evolution of these behaviors, the methods applied to study this topic, and the neuroendocrine basis and neural substrates mediating them.