Social facilitation in chickens: A different level of analysis

An assumption of the arousal ( D × H) model of social facilitation effects is that in an otherwise constant stimulus situation the simple presence or absence of a conspecific has a quantitative influence on the D component, and that the habit hierarchy in the situation ( H) is unaffected. However, certain evidence from avian subjects seemed inconsistent with the multiplicative effects predicted by the model, and experiments were conducted with the aim of resolving this discrepancy. In general, chickens were tested for consummatory responses in the company of companions, in isolation, or in the company of strangers. Clear findings emerged from these tests that showed that only the companion conditions were “facilitative”. Under the other test conditions there were qualitative (as opposed to merely quantitative) shifts in responses. Apparently, the different social test conditions evoked qualitatively different response hierarchies, and “facilitation” reflected this sort of shift rather than simple quantitative changes in arousal ( D) across conditions. It was argued, therefore, that the appropriate level of analysis for facilitation effects for animals in a free response situation is not within the ( D × H) envelope, but rather at the level of S (stimulus situation) in the S → ( D × H) → R formulation. Implications for the analysis of social facilitation effects in humans were discussed.