Dominance orders in animal societies: The self-organization hypothesis revisited

In previous papers (Theraulaz et al., 1995; Bonabeau et al., 1996) we sugge sted, following Hogeweg and Hesper (1983, 1985), that the formation of domi nance orders in animal societies could result from a self-organizing proces s involving a double reinforcement mechanism: winners reinforce their proba bility of winning and losers reinforce their probability of losing. This as sumption, and subsequent models relying on it, were based on empirical data on primitively eusocial wasps (Polistes dominulus). By reanalysing some of the experimental data that was previously thought to be irrelevant, we sho w that it is impossible to distinguish this assumption from a competing ass umption based on preexisting differences among individuals. We propose expe riments to help discriminate between the two assumptions and their correspo nding models-the self-organization model and the correlational model. We ur ge other researchers to be cautious when interpreting their dominance data with the 'self-organization mindset'; in particular, 'winner and loser effe cts', which are often considered to give support to the self-organization a ssumption, are equally consistent with the correlational assumption. (C) 19 99 Society for Mathematical Biology.