An engaging environment: improving nonhuman primate enrichment through choice of sound amplitude using broadband noise

Abstract

Certain types of music may be more effective than others in promoting the welfare of animals. A fundamental understanding of simple properties of sound is needed to determine how music affects animal welfare. Two experiments were conducted using nonhuman primates to investigate choices to variations in amplitude using broadband noise. The first experiment examined subject's preferences for seventy decibels of pink noise or no-sound. The results revealed that five of seven subjects preferred no-sound. Experiment two tested whether avoidance and escape responding were sensitive to changes in amplitude from zero to eighty decibels. The results showed that subjects engaged in escape responding equally to all amplitudes. Overall, these findings suggest that broadband noise up to eighty decibels does not function as a reinforcing or aversive stimuli. The methods used herein could be adapted to a larger set of experimental questions, to determine more effective environmental enrichment strategies.