Self-Reinforcing Dominance Interactions Between Virtual Males and Females. Hypothesis Generation for Primate Studies

Abstract

Although in group-living primates an individual's dominance position is a consequence of its social skills with both sexes, there are few data and hardly any theory on male-female dominance relationships. In order to stimulate a systematic study on this topic, I present a simple individual- oriented model on inter-sexual dominance and how it is influenced by species characteristics of primates, such as intensity of aggression and sex ratio. The model represents a virtual world inhab ited by entities that do nothing except grouping and performing dominance interactions in which the effects of winning and losing are self-reinforcing. VirtualMales start out with a higher winning tendency and are characterized by a higher intensity of aggression than VirtualFemales. To ensure comparability to behavioral patterns of real animals, I record the same behavioral aspects of the artificial entities as have been collected for real primates. Results show that due to the high impact of acts in fiercely aggressive VirtualSpecies, the variation in dominance values is larger than in mild ones. As a consequence, the rank of the most subordinate VirtualMale is lower than that of the lowest-ranking mild VirtualMale and, counter-intuitively, VirtualMales dominate relatively fewer VirtualFemales in fierce than mild species. Correspondence of model results to findings on primates allows us to use insight obtained from the model to derive hypotheses on the relation between intensity of aggression, sex ratio, male mounting behavior and female choice of primates.