Persistent neophobic behaviour in monkeys: A habit or a trait?

Studies on the effects of rearing conditions on behavioural development showed that most monkeys reared with surrogate mothers persistently avoided a big novel object (paper bag) whereas most monkeys reared by natural mothers would approach it. Conditioned fear and conditioned avoidance, observational learning, and lack of support by the mothers' presence could be excluded as possible causes; we established that the high incidence of phobic behaviour in surrogate-reared groups was caused by deprivation of maternal care. Results of further studies showed that the avoidance was not restricted to the object the Ss had been exposed to in infancy; monkeys still avoiding the bag at 2 years also avoided other big novel objects.

Mobile surrogate mothers and the development of exploratory behavior and radius of action in infant long-tailed macaques (Macaca fascicularis).

One of the effects of rearing young monkeys on surrogate mothers is a delay in the development of exploratory behavior. An important question is which difference between mother and surrogate mother caused this delay. We hypothesized that the mothers' carrying the infant through the environment promotes the development of exploratory behavior and the radius of action of infant macques.

Responses to novelty in phobic and non-phobic cynomolgus monkeys: the role of subject characteristics and object features.

In two previous studies it has been shown that most surrogate-reared cynomolgus monkeys became phobic of a harmless object (a big paper bag) while most mother-reared monkeys approached that object. Results of the first study seemed to indicate that the phobic reaction was restricted to the bag. Barnett and Cowan (Interdisciplinary Science Review, 1, 43-62, 1976) and Suomi (Anxiety disorder in childhood, pp.

Medial amygdala lesions in male rats reduce aggressive behavior: interference with experience.

The medial nucleus of the amygdala (am) has been implicated in a variety of social behaviors. The present experiment will test the hypothesis that the effect of am lesions on intermale aggressive behavior is due to interference with social learning processes. Small electrolytic lesions of the am had no significant effect in socially naive male rats.