Abstract: Darwin argued that between-species differences in intelligence were differences of degree, not of kind. The contemporary ecological approach to animal cognition argues that animals have evolved species-specific and problem-specific processes to solve problems associated with their particular ecological niches: thus different species use different processes, and within a species, different processes are used to tackle problems involving different inputs. This approach contrasts both with Darwin's view and with the general process view, according to which the same central processes of learning and memory are used across an extensive range of problems involving very different inputs. We review evidence relevant to the claim that the learning and memory performance of non-human animals varies according to the nature of the stimuli involved. We first discuss the resource distribution hypothesis, olfactory learning-set formation, and the 'biological constraints' literature, but find no convincing support from these topics for the ecological account of cognition. We then discuss the claim that the performance of birds in spatial tasks of learning and memory is superior in species that depend heavily upon stored food compared to species that either show less dependence upon stored food or do not store food. If it could be shown that storing species enjoy a superiority specifically in spatial (and not non-spatial) tasks, this would argue that spatial tasks are indeed solved using different processes from those used in non-spatial tasks. Our review of this literature does not find a consistent superiority of storing over non-storing birds in spatial tasks, and, in particular, no evidence of enhanced superiority of storing species when the task demands are increased, by, for example, increasing the number of items to be recalled or the duration of the retention period. We discuss also the observation that the hippocampus of storing birds is larger than that of non-storing birds, and find evidence contrary to the view that hippocampal enlargement is associated with enhanced spatial memory; we are, however, unable to suggest a convincing alternative explanation for hippocampal enlargement. The failure to find solid support for the ecological view supports the view that there are no qualitative differences in cognition between animal species in the processes of learning and memory. We also argue that our review supports our contention that speculation about the phylogenetic development and function of behavioural processes does not provide a solid basis for gaining insight into the nature of those processes. We end by confessing to a belief in one major qualitative difference in cognition in animals: we believe that humans alone are capable of acquiring language, and that it is this capacity that divides our intelligence so sharply from non-human intelligence.

Abstract: To understand the animal mind, we have to reconstruct how animals recognize the external world through their own eyes. For the reconstruction to be realistic, explanations must be made both in their proximate causes (brain mechanisms) as well as ultimate causes (evolutionary backgrounds). Here, we review recent advances in the behavioral, psychological, and system-neuroscience studies accomplished using the domestic chick as subjects. Diverse behavioral paradigms are compared (such as filial imprinting, sexual imprinting, one-trial passive avoidance learning, and reinforcement operant conditioning) in their behavioral characterizations (development, sensory and motor aspects of functions, fitness gains) and relevant brain mechanisms. We will stress that common brain regions are shared by these distinct paradigms, particularly those in the ventral telencephalic structures such as AIv (in the archistriatum) and LPO (in the medial striatum). Neuronal ensembles in these regions could code the chick's anticipation for forthcoming events, particularly the quality/quantity and the temporal proximity of rewards. Without the internal representation of the anticipated proximity in LPO, behavioral tolerance will be lost, and the chick makes impulsive choice for a less optimized option. Functional roles of these regions proved compatible with their anatomical counterparts in the mammalian brain, thus suggesting that the neural systems linking between the memorized past and the anticipated future have remained highly conservative through the evolution of the amniotic vertebrates during the last 300 million years. With the conservative nature in mind, research efforts should be oriented toward a unifying theory, which could explain behavioral deviations from optimized foraging, such as “naive curiosity,” “contra-freeloading,” “Concorde fallacy,” and “altruism.”

Abstract: The way in which cognitive functioning is affected by stressors is an important area of research for applied ethologists because stress caused by captive conditions may disrupt cognitive processes and lead to welfare and husbandry problems. Such problems may be minimised through an understanding of the links between stress and cognition. The effects of stress on cognitive function have been studied in disciplines ranging from human perceptual psychology to animal neuroscience. The aim of this paper is to provide an introduction to this research, focusing on the effects of stressors on attention, memory formation and memory recall. Findings from such a diverse literature with little apparent inter-disciplinary communication are inevitably complex and often contradictory. Nevertheless, some generalities do emerge. The idea that an inverted U-shaped relationship exists between an individual's state of stress or arousal and its ability to perform a cognitive task effectively, the so-called Yerkes-Dodson law, is commonly encountered. The law has limited explanatory value because it is unlikely that different stressors act on cognitive function via the same intervening, non-specific state. Furthermore, the law only provides a very general description of the relationship between stress and cognitive function. Empirical research on attention and memory processes reveals more specific findings. Stressors appear to cause shifts, lapses and narrowing of attention, and can also influence decision speed. These processes may be viewed as serving an adaptive role helping the animal to search for and scrutinise a source of danger. There is conflicting evidence as to whether hormones involved in the hypothalamic-pituitary-adrenal stress response play a part in these processes. These hormones and those involved in the sympathetic-adrenomedullary stress response do appear to play an important role in memory formation. Low or moderate concentrations of circulating glucocorticoids and catecholamines can enhance memory formation, while excessively high or prolonged elevations of these hormones can lead to memory disruption. The effects of stressors on memory recall are less clear. There is evidence for disruptive effects, and for facilitatory effects indicating state-dependent memory recall; events experienced under conditions of high arousal may be best recalled under similar conditions. Applied ethologists have the opportunity to extend work in this area, which often involves studies of single stressors/stress hormones acting in isolation and limited measures of cognitive function, by focusing on real-life husbandry stressors encountered by captive animals. This will yield fundamental information which also has direct relevance to animal welfare and management issues.

Abstract: Evidence is accumulating that cognitive abilities are shaped by the specific ecological conditions to which animals are exposed. Long-distance migratory birds may provide a striking example of this. Field observations have shown that, at least in some species, a substantial proportion of individuals return to the same breeding, wintering, and stopover sites in successive years. This observation suggests that migrants have evolved special cognitive abilities that enable them to accomplish these feats. Here we show that memory of a particular feeding site persisted for at least 12 months in a long-distance migrant, whereas a closely related nonmigrant could remember such a site for only 2 weeks. Thus, it seems that the migratory lifestyle has influenced the learning and memorizing capacities of migratory birds. These results build a bridge between field observations suggesting special memorization feats of migratory birds and previous neuroanatomical results from the same two species indicating an increase in relative hippocampal size from the first to the second year of life in the migrant but not in the nonmigrant.

Abstract: Scientists and equestrians continually seek to achieve a clearer understanding of equine learning behaviour and its implications for training. Behavioural and learning processes in the horse are likely to influence not only equine athletic success but also the usefulness of the horse as a domesticated species. However given the status and commercial importance of the animal, equine learning behaviour has received only limited investigation. Indeed most experimental studies on equine cognitive function to date have addressed behaviour, learning and conceptualisation processes at a moderately basic cognitive level compared to studies in other species. It is however, likely that the horses with the greatest ability to learn and form/understand concepts are those, which are better equipped to succeed in terms of the human-horse relationship and the contemporary training environment. Within equitation generally, interpretation of the behavioural processes and training of the desired responses in the horse are normally attempted using negative reinforcement strategies. On the other hand, experimental designs to actually induce and/or measure equine learning rely almost exclusively on primary positive reinforcement regimes. Employing two such different approaches may complicate interpretation and lead to difficulties in identifying problematic or undesirable behaviours in the horse. The visual system provides the horse with direct access to immediate environmental stimuli that affect behaviour but vision in the horse is of yet not fully investigated or understood. Further investigations of the equine visual system will benefit our understanding of equine perception, cognitive function and the subsequent link with learning and training. More detailed comparative investigations of feral or free-ranging and domestic horses may provide useful evidence of attention, stress and motivational issues affecting behavioural and learning processes in the horse. The challenge for scientists is, as always, to design and commission experiments that will investigate and provide insight into these processes in a manner that withstands scientific scrutiny.