Introduction

Mutual aid between and among members of a species may be the most potent force in evolution. This was the position taken by the Russian evolutionists who proposed that greater emphasis be placed on ‘mutual aid’ than on ‘survival of the fittest’ in the struggle for existence (Kropotkin, 1989; Todes, 1989). They noted that those species with the most highly evolved brains having the greatest brain weight and the most complex neocortical development show the greatest social cooperation and are the most sociable.

MacLean's (1990) emphasis on integrated brain function in social adaptation is critical to understanding the evolution of empathy. He and his colleagues provide an ethological perspective on the study of empathy in their paleo-ethological and ethological studies of behaviour. Evolutionary steps toward sociability are highlighted in his studies of audiovocal communication and on the effects of brain lesions on behaviour in lizards (Anolis carolinensis), rodents and squirrel monkeys. An increase in social behaviour and social responsiveness accompanies the evolutionary transition from reptiles to mammal-like reptiles to early mammals to primates and humans. Preston and de Waal (2002) suggest that in this evolutionary transition there are proximate and ultimate bases for empathy. Proximately, the perception of an object's state activates the individual's corresponding representations, which activate somatic and autonomic responses. They propose a Perception-Action Model (PAM) that along with experience can predict empathetic behaviour or its absence.