title: Does natural selection favour the Rescorla-Wagner rule?
abstract: A fundamental question relating to animal behaviour is how animals learn; in particular, how they come to associate stimuli with rewards. Numerous empirical findings can be explained by assuming that animals use some mechanism similar to the Rescorla-Wagner learning rule, which is a relatively simple and highly general method of updating the associative strength between different stimuli. However, the Rescorla-Wagner rule is often not optimal, which raises the question of why a rule with such properties should have evolved. We consider the evolution of learning rules in a simple environment where there exists an optimal rule of similar complexity to the Rescorla-Wagner rule. We show that because the Rescorla-Wagner rule is less sensitive to changes in its parameters than the optimal rule, there is a wider range of parameter values over which the rule structure is initially viable. Consequently, the Rescorla-Wagner rule can be favoured by natural selection, ahead of other rules which are more accurate.
authors.affiliation: School of Biological Sciences, Woodland Road, Bristol BS8 1UG, UK. pete.trimmer@gmail.com
authors.forename: Pete C
authors.initials: PC
authors.lastname: Trimmer
authors.forename: John M
authors.initials: JM
authors.lastname: McNamara
authors.forename: Alasdair I
authors.initials: AI
authors.lastname: Houston
authors.forename: James A R
authors.initials: JA
authors.lastname: Marshall
mesh_terms: D000818:Animals; D001245:Association Learning; D001522:Behavior, Animal; D005075:Biological Evolution; D003214:Conditioning, Classical; D008957:Models, Genetic; D008960:Models, Psychological; D012098:Reproduction / Q000235:genetics; D012641:Selection, Genetic