Social facilitation in a 'non-social' animal, the centipede Lithobius forficatus.

In a series of experiments in which centipedes ran alone (control), with a passive audience, and in coaction (two together), on a simple escape runway, significant differences from controls in latency and running speed were observed under audience conditions. The relevance of this apparent demonstration of social facilitation in an animal which is essentially not social is discussed in relation to the Zajonc (1965) 'mere presence' and Cottrell (1972) 'evaluation-apprehension' hypotheses of social facilitation.