Learning and unlearning mechanisms in animats and animals

This paper addresses the assumption, implicit in many robot and animat mode ls of learning, that learning and unlearning are a pair of symmetrical proc esses. Unlearning mechanisms supposedly erase or remove existing learning b ecause it is no longer relevant. Whether learning and unlearning result fro m the operation of symmetrical and antagonistic processes is an issue which has had a long but uneven history in animal and human psychology. This his tory is briefly recapitulated here. In particular, there is a contrast in t he significance of the antagonistic processes model in the area of motivati on compared to associative learning which has theoretical significance. For example, animat modelers frequently adopt a generic strengthening and weak ening mechanism for all forms of learning and motivation representations wi thout any consideration for its biological and psychological validity. In o rder to evaluate and question this, we examine the unlearning concept in a number of artefactual models drawn from a range of robotic and artificial l ife perspectives, and discuss their validity in terms of contemporary model s of animal learning and motivation. Finally, we outline an alternative vie w of learning/unlearning, based on a recent contingency model of causality learning in humans, which does not rely on antagonistic processes and may h ave applications for artefacts.