Is There Another New Factor in Evolution?

For 100 years it has been recognised that interactions between learning and evolution, such as the Baldwin effect (Baldwin, 1896), can be subtle and often counter-intuitive. Recently a new effect has been discussed: it is suggested that evolutionary progress towards one specific goal may be assisted by lifetime learning on a different task which may or may not be 'uncorrelated' (parisi, Nolfi & Cecconi, 1992). Here the phenomenon is reproduced in a simple scenario where the tasks are indeed uncorrelated -- 'Another New Factor' does indeed exist. The effect is then explained as being due to recovery from weight-perturbations, caused by mutation, in a neural network. It is a special case of a recently disciovered relearning effect (Harvey & Stone, 1996), the spontaneous recovery of perturbed associations by learning uncorrelated tasks.