Practice makes predictable: The differential effect of repeated sampling on behavioral and physiological responses in monkeys (1992)

Boccia, M. L., Broussard, C., Scanlan, J. et al.

Abstract

In our laboratory, we have made it a point to minimize the human-animal interactions, assuming that by minimizing interactions, we optimize experimental conditions by eliminating confounding handling effects. The results presented here, however, suggest that it may be necessary to reverse this thinking. ... We have noted that they [macaques] respond differently to male versus female caretakers and experimenters. ... Cortisol measures were also highly correlated with time to bleed. ... Monkeys that are older and more experienced with experimental protocols respond more quickly over the course of an experiment than do younger, less experienced monkeys. This affects the order in which the animal comes out of the gang cage for sampling. The hierarchy did not influence the sequence with which animals came out of the cage.