Social and environmental influences on self-aggression in monkeys

Three studies of stumptailed macaques examined the occurrence of self-aggression (SA) under different housing conditions. In group tests those environmental manipulations which increased social aggression decreased SA, but similar environmental conditions were found to increase SA in monkeys when tested in individual cages. SA increased in a group of monkeys in response to a temporarily impoverished environment. Like stereotyped movements reported for other species, SA may increase sensory input in poor environments, but this is probably not true for group-living monkeys, in which SA appears to be primarily a form of redirected social aggression. This research partially supported by SRC grant B/RG-98910 to A.S.C. Both J.R.A. and V.J.N. were partly supported by SRC studentships.