Dorothy Munkenbeck Fragaszy

Variability and adaptability in the genus Cebus

Capuchins (Cebus) present an array of similarities to humans and apes in morphology, behavior and life history which raise a host of questions about the relations of these features to each other and about their evolutionary origins. As a genus and as individuals, capuchins possess marked adaptability and great variability in behavior. These two characteristics contribute directly to the biological success of capuchins. Variability and adaptability are also hallmarks of human behavior.

Hand preference and performance on unimanual and bimanual tasks in capuchin monkeys (Cebus apella)

Patterns of manual preference and the extent to which preference provided a benefit in performance (movement time) were evaluated in 7 young adult capuchin monkeys (Cebus apella). Directions of preference were inconsistent within individual animals across home-cage activities, unimanual, and bimanual experimental tasks. Preferences were more strongly expressed in the experimental tasks than in the home cage. A left bias in the population for prehension, predicted by recent theories, was not evident in any setting. Movement time was moderately negatively correlated with degree of preference within experimental tasks. The benefit to performance conferred by lateral preference was not dependent on whether the right or left hand was preferred. Lateralization of prehension appears to be a flexible process in these monkeys, which can result in quickly realized benefits in some conditions.

Early Behavioral Development in Capuchins (Cebus)

Capuchin infants (genus Cebus) are born in a behaviorally more altricial state than is known for infants of other primate taxa except apes. Development in the first 2 months after birth is characterized by the major reorganization of sleeping and waking, assumption of postural control and the appearance of prehension. Capuchins develop postural control, prehension and locomotion later than do squirrel monkeys, baboons or macaques, presenting a pattern of motor development intermediate between these relatively more precocial genera and apes. Capuchins provide a useful model primate system in which to study development and its links with behavioral variability and life history.

Environmental challenges in groups of capuchins

We are interested in the behaviour of socially housed capuchin monkeys (Cebus apella) in captivity, particularly in their instrumental behaviour and the social context in which it occurs. We have found it useful to incorporate novel objects and tasks in our programme to provide environmental change.

Cognition in Squirrel Monkeys A Contemporary Perspective

The aims of this chapter are to review the recent literature on cognition in squirrel monkeys and to evaluate the findings with reference to normal, directed activity in natural environments; that is, in biological perspective. A biological perspective involves recognition that the functions of the nervous system (including learning, attention, perception, memory, and other aspects of cognition) have an impact on the organism’s life history, and that they must be evaluated in terms of that impact. We assume at the outset that the process of cognition provides the individual with potentially adaptable (and adaptive) ways to pick up information about the environment, to process this information, and to compare it against expectations (Neisser, 1976). This process guides behavior in a fundamental way. As Neisser (1976) puts it, cognition “is surely a matter of discovering what the environment is really like and adapting to it” (P. 9).

An Exploration of Manual Preference and Performance in Crabeating Macaques

An evolutionary perspective suggests that precursors of human lateral asymmetry should be present in nonhuman species. Indeed, many forms of asymmetry, including behavioral and anatomical, are found in nonhumans (e.g, Geschwind & Galaburda, 1984; Glick, 1985). Development of nonhuman models of asymmetric function are deemed critical to advances in our understanding of human asymmetry (Geschwind, 1985). Nonhuman primates have been a natural target of comparative studies of manual asymmetry (e.g., see references in Williams, 1985) because they share with humans a reliance on eye-hand coordination to obtain food, a reliance unique to the primate order (Gibson, 1986). This shared fundamental feature of motor organization makes it reasonable to expect that nonhuman primates might share other features of manual control evident in humans, including manual asymmetry.

Comparative studies of squirrel monkeys (Saimiri sciureus) and titi monkeys (Callicebus moloch): performance on choice tasks in near space

Squirrel monkeys (Saimiri sciureus) and titi monkeys (Callicebus moloch) were studied in tasks involving reaching for food in near space (arms reach). Although performance by monkeys of the two species differed in several ways familiar from previous studies, the species did not differ in the tendency to adopt a habitual position or limb during reaching. The findings contrast with previous work on spatial preferences in these species in tasks involving movement of the whole body. Together with the results of previous studies on movement patterns in these two species, the findings are placed in a comparative psychological framework of the proximate sources of use of space in nature.

Movie S3 from Unique perceptuomotor control of stone hammer in wild monkeys

A representative bearded capuchin monkey, Teimoso (body mass = 3.6 kg), is striking an intact piacava nut with a 1.91 kg hammer.