Abstract: Episodic memory involves the encoding and storage of memories concerned with unique personal experiences and their subsequent recall, and it has long been the subject of intensive investigation in humans. According to Tulving's classical definition, episodic memory “receives and stores information about temporally dated episodes or events and temporal-spatial relations among these events.” Thus, episodic memory provides information about the `what' and `when' of events (`temporally dated experiences') and about `where' they happened (`temporal-spatial relations'). The storage and subsequent recall of this episodic information was thought to be beyond the memory capabilities of nonhuman animals. Although there are many laboratory procedures for investigating memory for discrete past episodes, until recently there were no previous studies that fully satisfied the criteria of Tulving's definition: they can all be explained in much simpler terms than episodic memory. However, current studies of memory for cache sites in food-storing jays provide an ethologically valid model for testing episodic-like memory in animals, thereby bridging the gap between human and animal studies memory. There is now a pressing need to adapt these experimental tests of episodic memory for other animals. Given the potential power of transgenic and knock-out procedures for investigating the genetic and molecular bases of learning and memory in laboratory rodents, not to mention the wealth of knowledge about the neuroanatomy and neurophysiology of the rodent hippocampus (a brain area heavily implicated in episodic memory), an obvious next step is to develop a rodent model of episodic-like memory based on the food-storing bird paradigm. The development of a rodent model system could make an important contribution to our understanding of the neural, molecular, and behavioral mechanisms of mammalian episodic memory.

Abstract: Fourteen riding horses of mixed age and breed were randomly allocated to observer and control treatments. An additional horse was pre-trained as a demonstrator to walk the 13.8 m length of the test arena and select one of two food buckets using colour and pattern cues. Observer horses were exposed to correct performances of the task by the trained demonstrator, for 20 trials held over 2 days. Control horses were subjected to the same handling and placement procedures as the observer horses but without exposure to the behaviour of the demonstrator. The third day for all subjects was designated as a test day. Each subject was released individually in a predetermined place in the arena, and the latency to walk the length of the test arena to the food buckets, the latency to feed, the identity of the bucket approached and the identity of the bucket selected were recorded on ten consecutive trials. During tests both food buckets contained food to minimize the possibility of individual trial and error learning. On the first trial the mean latency to approach the goal area was 18 s for observer horses, compared with 119 s for control horses (t = 2.8, d.f. = 12, P < 0.01) and the mean latency to eat was 35 s for observer horses, compared with 181 s for control horses (t = 4.86, d.f. = 11, P < 0.001). However, observer horses were no more likely to choose the demonstrated bucket than control horses on the first trial. Twelve of the 14 horses decreased their latency to approach the goal area during the series of ten trials, but there were no significant changes in the buckets selected.

Abstract: Domestic dogs (Canis familiaris) and great apes from the genus Pan were tested on a series of object choice tasks. In each task, the location of hidden food was indicated for subjects by some kind of communicative, behavioral, or physical cue. On the basis of differences in the ecologies of these 2 genera, as well as on previous research, the authors hypothesized that dogs should be especially skillful in using human communicative cues such as the pointing gesture, whereas apes should be especially skillful in using physical, causal cues such as food in a cup making noise when it is shaken. The overall pattern of performance by the 2 genera strongly supported this social-dog, causal-ape hypothesis. This result is discussed in terms of apes' adaptations for complex, extractive foraging and dogs' adaptations, during the domestication process, for cooperative communication with humans.

Abstract: Observational learning in chimpanzees and young children was investigated using an artificial fruit designed as an analog of natural foraging problems faced by primates. Each of 3 principal components could be removed in 2 alternative ways, demonstration of only one of which was watched by each subject. This permitted subsequent imitation by subjects to be distinguished from stimulus enhancement. Children aged 2-4 years evidenced imitation for 2 components, but also achieved demonstrated outcomes through their own techniques. Chimpanzees relied even more on their own techniques, but they did imitate elements of 1 component of the task. To our knowledge, this is the first experimental evidence of chimpanzee imitation in a functional task designed to simulate foraging behavior hypothesized to be transmitted culturally in the wild.

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.