Abstract: We review socially biased learning about food and problem solving in monkeys, relying especially on studies with tufted capuchin monkeys (Cebus apella) and callitrichid monkeys. Capuchin monkeys most effectively learn to solve a new problem when they can act jointly with an experienced partner in a socially tolerant setting and when the problem can be solved by direct action on an object or substrate, but they do not learn by imitation. Capuchin monkeys are motivated to eat foods, whether familiar or novel, when they are with others that are eating, regardless of what the others are eating. Thus, social bias in learning about foods is indirect and mediated by facilitation of feeding. In most respects, social biases in learning are similar in capuchins and callitrichids, except that callitrichids provide more specific behavioral cues to others about the availability and palatability of foods. Callitrichids generally are more tolerant toward group members and coordinate their activity in space and time more closely than capuchins do. These characteristics support stronger social biases in learning in callitrichids than in capuchins in some situations. On the other hand, callitrichids' more limited range of manipulative behaviors, greater neophobia, and greater sensitivity to the risk of predation restricts what these monkeys learn in comparison with capuchins. We suggest that socially biased learning is always the collective outcome of interacting physical, social, and individual factors, and that differences across populations and species in social bias in learning reflect variations in all these dimensions. Progress in understanding socially biased learning in nonhuman species will be aided by the development of appropriately detailed models of the richly interconnected processes affecting learning.

Abstract: Two experiments addressed contradictory claims about causal reasoning in elephants. In Experiment 1, 4 Asian elephants (Elephas maximus) were pretrained to remove a lid from the top of a bucket and retrieve a food reward. Subsequently, in the first 5 critical trials, when the lid was placed alongside the bucket and no longer obstructed access to the reward, each elephant continued to remove the lid before retrieving the reward. Experiment 2, which involved 11 additional elephants and variations of the original design, yielded similarly counterintuitive observations. Although the results are open to alternative interpretations, they appear more consistent with associative learning than with causal reasoning. Future applications of Fabrean methodologies (J. H. Fabre, 1915) to animal cognition are proposed.

Abstract: S. T. Boysen and G. G. Berntson (1995) found that chimpanzees performed poorly on a reversed contingency task in which they had to point to the smaller of 2 food quantities to acquire the larger quantity. The authors compared the performance of 4 great ape species (Pan troglodytes, Pongo pygmaeus, Pan paniscus, and Gorilla gorilla) on the reversed contingency task while manipulating food quantity (0-4 or 1-4) and food visibility (visible pairs or covered pairs). Results showed no systematic species differences but large individual differences. Some individuals of each species were able to solve the reversed contingency task. Both quantity and visibility of the food items had a significant effect on performance. Subjects performed better when the disparity between quantities was smaller and the quantities were not directly visible.

Abstract: We conducted four experiments in order to investigate whether pigeons' responses to a recently attended (i.e., recently pecked) location are inhibited. In Experiments 1 and 2, stimulus displays were similar to those used in studies of inhibition of return (IOR) with humans; responses to cued targets tended to be facilitated rather than inhibited. In Experiments 3 and 4, birds were presented with stimulus displays that mimicked clusters of small grains and were relatively localized, which should have been more appropriate for detecting IOR in pigeons. The results from these experiments again provided evidence for facilitation of responding to cued targets, rather than for IOR.