Human-directed contra-aggression training using positive reinforcement for indoor-housed rhesus macaques (2010)

Minier, D. E., Tatum, L., McCowan, B.

Abstract

The quality of human-animal interactions can be an indicator of well-being in laboratory primates and increased anxiety-related behavior, such as aggression, may compromise an animal's ability to provide research outcomes reflective of normal function. The objective of this study was to improve human-animal management relationships by testing the effects of positive reinforcement training (PRT) on reducing human-directed aggression in rhesus macaques. Using a blind experimental approach for assessing aggressiveness (human intruder test, husbandry response test) in groups of subjects either untrained [controls, N=5], trained by a single trainer [N=5] or trained by multiple trainers [N=5], we evaluated the change in aggressiveness during baseline conditions, one-day post-training, and six-weeks post-training. Results via Poisson regression analysis showed (1) significant reduction in aggression in post-training to baseline human intruder test for the single trainer group [P<0.01] but not in multiple trainer [P=0.08] or untrained [P=1.00] groups; and (2) significant decrease in fear in the husbandry response test for both single trainer [P<0.001] and multiple trainer [P<0.002] but not the untrained group [P=0.10]. These preliminary results indicate that contra-aggression training and PRT in general can substantially reduce aggressiveness and fear in nonhuman primates and significantly enhance their wellbeing during routine research and medical procedures; however, the approach of training such as single versus multiple trainers can affect the efficacy and thus outcome of training benefits.