Influence of Spatial Environment On Development of Mother-Infant Interaction in Pigtail Monkeys

Abstract

Three groups of infant pigtail monkeys (Macaca nemestrina) were observed for the first 24 weeks of life: Group G consisted of 3 mother-infant pairs living in a heterogeneous social group of 20 monkeys ; Group L included 3 pairs maintained in individual large cages, and Group S consisted of 4 pairs maintained in individual small cages. Groups S and L infants did not differ in duration of time spent away from mother. Group G infants left later and for less time by the first eighth week, but from the 16th week on they spent more time separated from their mothers. Group S mothers punished their infants more than Group L mothers, and punishment was almost absent in Group G. At 28 weeks, Groups L and S infants were placed in a playpen situation where initial differences between the groups disappeared after about 4 weeks. At 36 weeks infants were separated from their mothers; two weeks later they formed a stable rank order as determined by a water dominance test.