Compared the abilities of 3 mother-reared and 3 human-raised (enculturated) chimpanzees and 16 human toddlers to imitatively learn novel actions on objects. Found that mother-reared chimpanzees were poorer imitators than both enculturated chimpanzees and human children, who did not differ from one another in imitative learning. On time delay…

Three groups of macaque mother/infant dyads were observed while each lived in ecological settings that differed in level of foraging demand and, hence, the amount of work each mother was required to perform to obtain her daily rations. Findings suggest that in monkeys, as in humans, when mothers are psychologically unavailable to their infants,…

Findings are consistent with behavior observed in rhesus monkeys reared under similar conditions, thereby broadening the base from which to extrapolate to human development. (Authors)

Results showed that, although adult male monkeys are less active and more stable in their behavioral levels than mates or offspring, they clearly distribute both initiates and responses differently to male offspring, female offspring, mates and infant and adult monkeys from other families. Implications for human father-infant interaction are…

Eight stump-tailed macaques were reared individually and either given all of their daily social experience in darkness or given half in the dark and half in the light. Results suggest that vision is especially important in the maintenance of assertive behaviors and in the instigation and direction of aggressive behaviors. (Author/RH)

This article attempts to illustrate the value of a psychobiological approach to the study of a particular behavior; in this case, vocalization of infant primates following loss of the mother. (PCB)

Four-month-old rhesus monkeys were removed from their social group under three different conditions of perceptual isolation from their mothers and peers. Infant behavior was recorded and blood samples were obtained for analysis of plasma cortisol. Infants never showed signs of depression; their responses following separation were seen as attempts…

Capacity of infant monkeys to mount an antibody response to viral challenge was evaluated after monkeys' removal from their mothers in several social and physical environments. Results indicated that trauma of separation was reduced when infants were familiar with the separation environment or familiar social companions were available. (PCB)

Compared comprehension of novel communicative signs to assist 2.5- and 3-year-old humans, chimpanzees, and orangutans find hidden objects during a hiding-finding game. Found that children at both ages performed above chance with all signs. No ape performed above chance for any signs not known before the experiment despite three times as many…

Stable characteristics of female rhesus monkeys with offspring, in terms of Confident and Excitable scores, were significantly positively correlated with the respective scores of their female offspring but not their male offspring. Female parents' Excitable scores were significantly negatively correlated with males' Confident scores. How this…