Co-evolution of Personality and  the Environment
Wander Jager, Marco A. Janssen
w.jager@bdk.rug.nl, m.janssen@feweb.vu.nl


     In this paper we focus on the cognitive costs that are involved in  more reasoned decision-making strategies. We argue that a  lower investment of cognitive effort, e.g., by satisficing or  imitating the behaviour of others, may be beneficial both for the  individual as for the sustainability of the population as a whole.  We further argue that the most effective distribution of decision- strategies will be related to the stability of the environment  people live in. Hence personality factors that determine the  preference for a certain distribution are subject to evolutionary  pressures. Starting from a multi-theoretical perspective on  behaviour we have developed a multi-agent model. In this model  several decision-making strategies have been formalised. These  strategies differ with respect to the cognitive effort they require  and their individual versus social orientation. Experiments with  this multi-agent model show that the type of personality that is  most frequent in a population depends on the stability of the  environment. In unstable environment, agents with higher  aspiration levels and lower uncertainty tolerance have an  evolutionary benefit. Moreover, the results show that  sustainability can be reached when agents with particular type of  personalities evolve. The model experiments also demonstrate  that evolutionary pressures favour a mix of cognitive strategies.  Finally we demonstrate that an unstable environment favours the  development of a smaller population investing more cognitive  effort in their decision making process.