Abstract: Aging pets often suffer a decline in cognitive function (eg, memory,learning, perception, awareness) likely associated with age-dependent brain alterations. Clinically, cognitive dysfunction may result in various behavioral signs, including disorientation; forgetting of previously learned behaviors, such as house training; alterations in the manner in which the pet interacts with people or other pets;onset of new fears and anxiety; decreased recognition of people, places, or pets; and other signs of deteriorating memory and learning ability. Many medical problems, including other forms of brain pathologic conditions, can contribute to these signs. The practitioner must first determine the cause of the behavioral signs and then determine an appropriate course of treatment, bearing in mind the constraints of the aging process. A diagnosis of cognitive dysfunction syndrome is made once other medical and behavioral causes are ruled out.

Abstract: Dogs can use the placement of an arbitrary marker to locate hidden food in an object-choice situation. We tested domestic dogs (Canis familiaris) in three studies aimed at pinning down the relative contributions of the human's hand and the marker itself. We baited one of two cups (outside of the dogs' view) and gave the dog a communicative cue to find the food. Study 1 systematically varied dogs' perceptual access to the marker placing event, so that dogs saw either the whole human, the hand only, the marker only, or nothing. Follow-up trials investigated the effect of removing the marker before the dog's choice. Dogs used the marker as a communicative cue even when it had been removed prior to the dog's choice and attached more importance to this cue than to the hand that placed it although the presence of the hand boosted performance when it appeared together with the marker. Study 2 directly contrasted the importance of the hand and the marker and revealed that the effect of the marker diminished if it had been associated with both cups. In contrast touching both cups with the hand had no effect on performance. Study 3 investigated whether the means of marker placement (intentional or accidental) had an effect on dogs' choices. Results showed that dogs did not differentiate intentional and accidental placing of the marker. These results suggest that dogs use the marker as a genuine communicative cue quite independently from the experimenter's actions.

Abstract: Two chimpanzees and a rhesus macaque rapidly learned the ordinal relations between 5 colors of containers (plastic eggs) when all containers of a given color contained a specific number of identical food items. All 3 animals also performed at high levels when comparing sets of containers with sets of visible food items. This indicates that the animals learned the approximate quantity of food items in containers of a given color. However, all animals failed in a summation task, in which a single container was compared with a set of 2 containers of a lesser individual quantity but a greater combined quantity. This difficulty was not overcome by sequential presentation of containers into opaque receptacles, but performance improved if the quantitative difference between sizes was very large.

Abstract: Domestic dogs are unusually skilled at reading human social and communicative behavior--even more so than our nearest primate relatives. For example, they use human social and communicative behavior (e.g. a pointing gesture) to find hidden food, and they know what the human can and cannot see in various situations. Recent comparisons between canid species suggest that these unusual social skills have a heritable component and initially evolved during domestication as a result of selection on systems mediating fear and aggression towards humans. Differences in chimpanzee and human temperament suggest that a similar process may have been an important catalyst leading to the evolution of unusual social skills in our own species. The study of convergent evolution provides an exciting opportunity to gain further insights into the evolutionary processes leading to human-like forms of cooperation and communication.

Abstract: Ten patients with semantic dementia resulting from bilateral anterior temporal lobe atrophy, and 10 matched controls, were tested on an object recognition task in which they were invited to choose (from a four-item array) the picture representing “the same thing” as an object picture that they had just inspected and attempted to name. The target in the response array was never physically identical to the studied picture but differed from it – in the various conditions – in size, angle of view, colour or exemplar (e.g. a different breed of dog). In one test block for each patient, the response array was presented immediately after the studied picture was removed; in another block, a 2 min filled delay was inserted between study and test. The patients performed relatively well when the studied object and target response differed only in the size of the picture on the page, but were significantly impaired as a group in the other three type-of-change conditions, even with no delay between study and test. The five patients whose structural brain imaging revealed major right-temporal atrophy were more impaired overall, and also more affected by the 2 min delay, than the five patients with an asymmetric pattern characterised by predominant left-sided atrophy. These results are interpreted in terms of a hypothesis that successful classification of an object token as an object type is not a pre-semantic ability but rather results from interaction of perceptual and conceptual processing.