Abstract: Many primates, including humans, live in complex hierarchical societies where social context and status affect daily life. Nevertheless, primate learning studies typically test single animals in limited laboratory settings where the important effects of social interactions and relationships cannot be studied. To investigate the impact of sociality on associative learning, we compared the individual performances of group-tested rhesus monkeys (Macaca mulatta) across various social contexts. We used a traditional discrimination paradigm that measures an animal's ability to form associations between cues and the obtaining of food in choice situations; but we adapted the task for group testing. After training a 55-member colony to separate on command into two subgroups, composed of either high- or low-status families, we exposed animals to two color discrimination problems, one with all monkeys present (combined condition), the other in their “dominant” and “subordinate” cohorts (split condition). Next, we manipulated learning history by testing animals on the same problems, but with the social contexts reversed. Monkeys from dominant families excelled in all conditions, but subordinates performed well in the split condition only, regardless of learning history. Subordinate animals had learned the associations, but expressed their knowledge only when segregated from higher-ranking animals. Because aggressive behavior was rare, performance deficits probably reflected voluntary inhibition. This experimental evidence of rank-related, social modulation of performance calls for greater consideration of social factors when assessing learning and may also have relevance for the evaluation of human scholastic achievement.

Abstract: The definition of tool proposed by Beck (1980) is still the one referred to in ethology when discussing the question of tool-use in animals, and its pertinence is rarely questioned. However, observations on technical behaviours in animals have multiplied over the last 20 years, and these have profoundly altered our earlier representations. In the present article, we show that Beck's definition is insufficient and that it does not, in fact, work. More generally, we replace a theory of tools with a theory of mediations of actions to account for technical behaviours in animals. We show that a culturally overcharged notion such as that of tool hinders our perception of the diversity and the complexity of tool uses. By speaking of mediations of actions and not of tools, we eliminate the problem of first defining the pertinent object (is it a tool or not?) and are free to concentrate on the means by which the animal externalizes its actions and thus procures greater means of acting on these within a group. In so doing, we prepare the ground for a genuine evolutionary understanding of the dynamics of actions within a given animal population. Whereas, with a few exceptions, ethologists have always separated the question of techniques from that of social behaviour, we emphasize the importance of an ecology of mediations of actions for understanding the structure and dynamics of animal societies, in particular by attempting to rethink such notions as “culture” in the perspective of a general analysis of mediations of actions.

Abstract: When novel behaviour patterns spread through animal populations, typically one animal will initiate the diffusion. It is not known whether such 'innovators' are particularly creative individuals, individuals exposed to the appropriate environmental contingencies, or individuals in a particular motivational state. We describe three experiments that investigated the factors influencing foraging innovation in the guppy Poecilia reticulata. We exposed small laboratory populations of fish to novel foraging tasks, which involved exploration and problem solving to locate a novel food source. Experiments 1 and 2 found that (1) females were more likely to innovate than males, (2) food-deprived fish were more likely to innovate than nonfood-deprived subjects, and (3) smaller fish were more likely to innovate than larger fish. We suggest that the sex difference may reflect parental investment asymmetries in males and females. Experiment 3 found that past innovators were more likely to innovate than past noninnovators. Collectively, the results suggest that differences in foraging innovation in guppies are best accounted for by differences in motivational state, but, in addition, guppies may vary in their predisposition to innovate. Copyright 1999 The Association for the Study of Animal Behaviour.

Abstract: We conducted playback experiments with wild bottlenose dolphins, Tursiops truncatus, to determine whether there is sufficient information in their individually distinctive signature whistles for individual recognition. We conducted experiments with members of a resident community of dolphins in waters near Sarasota, Florida, during temporary capture-release projects. We used a paired playback design, wherein the same two whistle sequences were predicted to evoke opposite responses from two different target animals. This design controlled for any unknown cues that may have been present in the playback stimuli. We predicted that mothers would respond more strongly to the whistles of their own independent offspring than to the whistles of a familiar, similar-aged nonoffspring. Similarly, we predicted that independent offspring would respond more strongly to the whistles of their own mother than to the whistles of a familiar, similar-aged female. Target animals were significantly (P<0.02) more likely to respond to the predicted stimuli, with responses measured by the number of head turns towards the playback speaker. In bottlenose dolphin societies, stable, individual-specific relationships are intermixed with fluid patterns of association between individuals. In primate species that live in similar 'fission-fusion' type societies, individual recognition is commonplace. Thus, when taken in the context of what is known about the social structure and behaviour of bottlenose dolphins, these playback experiments suggest that signature whistles are used for individual recognition. Copyright 1999 The Association for the Study of Animal Behaviour.