Pathogen Load and the Nature of Ingroup Derogation: Evolution of Ingroup Derogation Based on the Sexual Penna Model

摘要

Ingroup derogation is a preference and affinity for outgroup members over ingroup members which contradicts both expert and lay beliefs. In present study, we further tested the evolutionary Ingroup derogation hypothesis by using computational modeling analysis based on the modified sexual Penna model to simulate the evolution of ingroup derogation In conditions that both the Ingroup and outgroup members can incur disease threats. The results showed that the difference of pathogen loads between two different regions would affect the intergroup attitudes of the social groups within these two regions. That is, the social group in the area with relative lower prevalence of disease would display the ingroup favoritism attitude, while the group in the area with relatively higher prevalence of disease would evolve the ingroup derogation attitude. In addition, the results also showed that the strength of the ingroup derogation attitude was positively correlated with this difference. These results indicate that ingroup derogation could be evolved under a broad range of conditions which are easily to be satisfied In the real world and suggest that Ingroup derogation is a special adaptation to a particular situation in which ingroup members pose more threat of diseases than outgroup members.