Abstract: ven young humans show sensitivity to the accuracy and reliability of informants’ reports. Children are selective in soliciting information and in accepting claims. Recent research has also investigated domestic dogs’ (Canis familiaris) sensitivity to agreement among human informants. Such research utilizing a common human pointing gesture to which dogs are sensitive in a food retrieval paradigm suggests that dogs might choose among informants according to the number of points exhibited, rather than the number of individuals indicating a particular location. Here, we further investigated dogs’ use of information from human informants using a stationary pointing gesture, as well as the conditions under which dogs would utilize a stationary point. First, we explored whether the number of points or the number of individuals more strongly influenced dogs’ choices. To this end, dogs encountered a choice situation in which the number of points exhibited toward a particular location and the number of individuals exhibiting those points conflicted. Results indicated that dogs chose in accordance with the number of points exhibited toward a particular location. In a second experiment, we explored the possibility that previously learned associations drove dogs’ responses to the stationary pointing gesture. In this experiment, dogs encountered a choice situation in which artificial hands exhibited a stationary pointing gesture toward or away from choice locations in the absence of humans. Dogs chose the location to which the artificial hand pointed. These results are consistent with the notion that dogs may respond to a human pointing gesture due to their past-learning history.

Abstract: A tool-throwing task was used to test whether capuchin monkeys understand the difference between functionally appropriate and functionally inappropriate tools. A group of monkeys was trained to obtain a sticky treat from a container outside their enclosure using a projectile attached to one end of an anchored line. Subsequently, these monkeys were given choice tests between functional and nonfunctional versions of tools used in training. A different feature of the tool was varied between alternatives in each choice test. The monkeys chose to use functional tools significantly more often than nonfunctional tools in early exposures to each choice test. A second experiment tested whether these subjects, as well as a second group of minimally trained participants, could distinguish between functional and nonfunctional tools that appeared different from those used in training. A new set of design features was varied between tools in these choice tests. All participants continued to choose functional tools significantly more often than nonfunctional tools, regardless of their tool-throwing experience or the novel appearance of the tools. These results suggest that capuchin monkeys, like chimpanzees studied in similar experiments, are sensitive to a variety of functionally relevant tool features.

Abstract: We investigated the ability to perceive depth from shading, one of the pictorial depth cues, in three chimpanzee infants aged 4-10 months old, using a preferential reaching task commonly used to study pictorial depth perception in human infants. The chimpanzee infants reached significantly more to three-dimensional toys than to pictures thereof and more to the three-dimensional convex than to the concave. Furthermore, two of the three infants reached significantly more to the photographic convex than to the photographic concave. These infants also looked longer at the photographic convex than the concave. Our results suggest that chimpanzees perceive, at least as early as the latter half of the first year of life, pictorial depth defined by shading information. Photographic convexes contain richer information about pictorial depth (e.g., attached shadow, cast shadow, highlighted area, and global difference in brightness) than simple computer-graphic graded patterns. These cues together might facilitate the infants' perception of depth from shading.

Abstract: This paper examines the contribution of stimulus processing to animal logics. In the classic functionalist S-O-R view of learning (and cognition), stimuli provide the raw material to which the organism applies its cognitive processes-its logic, which may be taxon-specific. Stimuli may contribute to the logic of the organism's response, and may do so in taxon-specific ways. Firstly, any non-trivial stimulus has an internal organization that may constrain or bias the way that the organism addresses it; since stimuli can only be defined relative to the organism's perceptual apparatus, and this apparatus is taxon-specific, such constraints or biases will often be taxon-specific. Secondly, the representation of a stimulus that the perceptual system builds, and the analysis it makes of this representation, may provide a model for the synthesis and analysis done at a more cognitive level. Such a model is plausible for evolutionary reasons: perceptual analysis was probably perfected before cognitive analysis in the evolutionary history of the vertebrates. Like stimulus-driven analysis, such perceptually modelled cognition may be taxon-specific because of the taxon-specificity of the perceptual apparatus. However, it may also be the case that different taxa are able to free themselves from the stimulus logic, and therefore apply a more abstract logic, to different extents. This thesis is defended with reference to two examples of cases where animals' cognitive logic seems to be isomorphic with perceptual logic, specifically in the case of pigeons' attention to global and local information in visual stimuli, and dogs' failure to comprehend means-end relationships in string-pulling tasks.

Abstract: Cognitive mechanisms are an important part of the organization of the behavior systems of animals. In the wild, animals regularly face problems that they must overcome in order to survive and thrive. Solving such problems often requires animals to process, store, retrieve, and act upon information from the environment--in other words, to use their cognitive skills. For example, animals may have to use navigational, tool-making or cooperative social skills in order to procure their food. However, many enrichment programs for captive animals do not include the integration of these types of cognitive challenges. Thus, foraging enrichments typically are designed to facilitate the physical expression of feeding behaviors such as food-searching and food consumption, but not to facilitate complex problem solving behaviors related to food acquisition. Challenging animals by presenting them with problems is almost certainly a source of frustration and stress. However, we suggest here that this is an important, and even necessary, feature of an enrichment program, as long as animals also possess the skills and resources to effectively solve the problems with which they are presented. We discuss this with reference to theories about the emotional consequences of coping with challenge, the association between lack of challenge and the development of abnormal behavior, and the benefits of stress (arousal) in facilitating learning and memory of relevant skills. Much remains to be done to provide empirical support for these theories. However, they do point the way to a practical approach to improving animal welfare--to design enrichments to facilitate the cognitive mechanisms which underlie the performance of complex behaviors that cannot be performed due to the restrictions inherent to the captive environment.