Abstract: This study examines the role of observation during the formation of triads in female domestic hens. Results indicate that during hierarchy formation, a hen observing agonistic interactions and conflict settlement between its former dominant and a stranger uses this information when in turn confronted by the latter. Under a first condition (E, N = 15 triads), bystanders witnessed their prior dominant being defeated by a stranger before being introduced to them. In a second condition (C1, N = 16 triads), bystanders witnessed the victory of their prior dominant over a stranger. In a third condition (C2, N = 15 triads), bystanders witnessed two strangers establishing a dominance relationship before being introduced to their prior dominant and to a stranger the former had just defeated. The behavioural strategies of bystanders depended on the issue of the conflict they had witnessed. Bystanders of the E condition behaved as having no chance of defeating the stranger. They never initiated an attack against it, and upon being attacked, readily submitted in turn to the stranger. On the contrary, bystanders of the C1 condition behaved as having some chances against the stranger. They initiated attacks in 50% of cases, and won 50% of conflicts against the stranger. Under condition C2, bystanders first initiated contact with the strangers in only 27% of cases, which approximates the average of their chances for defeating the stranger. However, bystanders finally defeated the strangers in 40% of cases. These results suggest that bystanders of conditions E and C1 gained some information on the relationship existing between their prior dominant and the stranger and that they used it coherently, perhaps through transitive inference, thus contributing to the existence of transitive relationships within the triads. Alternate explanations are examined.

Abstract: To emphasize the effects of group- and single housing of kennelled dogs, the behavior of 211 dogs in two German animal shelters was tested and observed. After being placed, 197 of the dogs' new owners were interviewed.
Although 51% of the German animal shelters already keep dogs in groups, there is strong prejudice against group housing because of the fear of fights. This study demonstrates that this apprehension is unfounded. Ninety-one percent of the social confrontations between dogs housed together were settled by the use of behavioral rituals. Keeping dogs in groups, furthermore, leads to a significant reduction in noise emission (p<.001). Group housing fulfills the dog's need for social interaction and the need to move. Dogs that were housed in groups displayed a closer human-animal relationship (80%) than those that had been kept individually (43%). A high percentage of individually housed dogs suffered from behavioral problems (31%) and 10% developed stereotypes. The percentage of behaviorally disturbed dogs observed in group housing was 11%, and stereotyped forms of behavior did not occur. Dogs who had been kept in groups were, on average, placed within 10 days, and were returned to the animal shelter less often (9%) compared to those housed individually (25%). Dogs that were housed separately needed an average of 17 days to be placed. Even after being placed, there is a correlation between the animal shelter's type of housing and the dog's behavior. Within four weeks after picking up their pet, 88% of the owners of dogs that had been housed individually complained of problems compared to the owners of the dogs that had been kept in groups, 53% of whom were completely satisfied with the adoption.
Despite the fact that these results might be influenced by the small number of shelters examined, the study leads to the conclusion that keeping dogs in groups is a suitable alternative for dog housing in animal shelters and, for the animals' welfare, is preferable to individual housing.

Abstract: To test the hypothesis that selection for spatial abilities which require birds to locate and to return accurately to host nests has produced an enlarged hippocampus in brood parasites, three species of cowbird were compared. In shiny cowbirds, females search for host nests without the assistance of the male; in screaming cowbirds, males and females inspect hosts' nests together; in bay-winged cowbirds, neither sex searches because this species is not a brood parasite. As predicted, the two parasitic species had a relatively larger hippocampus than the non-parasitic species. There were no sex differences in relative hippocampus size in screaming or bay-winged cowbirds, but female shiny cowbirds had a larger hippocampus than the male.

Abstract: We recorded electrical activity from 532 neurons in the rostral part of inferior area 6 (area F5) of two macaque monkeys. Previous data had shown that neurons of this area discharge during goal-directed hand and mouth movements. We describe here the properties of a newly discovered set of F5 neurons ( mirror neurons', n = 92) all of which became active both when the monkey performed a given action and when it observed a similar action performed by the experimenter. Mirror neurons, in order to be visually triggered, required an interaction between the agent of the action and the object of it. The sight of the agent alone or of the object alone (three-dimensional objects, food) were ineffective. Hand and the mouth were by far the most effective agents. The actions most represented among those activating mirror neurons were grasping, manipulating and placing. In most mirror neurons (92%) there was a clear relation between the visual action they responded to and the motor response they coded. In [~]30% of mirror neurons the congruence was very strict and the effective observed and executed actions corresponded both in terms of general action (e.g. grasping) and in terms of the way in which that action was executed (e.g. precision grip). We conclude by proposing that mirror neurons form a system for matching observation and execution of motor actions. We discuss the possible role of this system in action recognition and, given the proposed homology between F5 and human Brocca's region, we posit that a matching system, similar to that of mirror neurons exists in humans and could be involved in recognition of actions as well as phonetic gestures.

Abstract: When pigeons acquire a simple simultaneous discrimination, some of the value acquired by the S+ transfers to the S-. The mechanism underlying this transfer of value was examined in three experiments. In Experiment 1, pigeons trained on two simultaneous discriminations (A + B- and C +/- D-) showed a preference for B over D. This preference was reduced, however, following the devaluation of A. In Experiment 2, when after the same original training, value was given to D, the pigeons' preference for C did not significantly increase. In Experiment 3, when both discriminations involved partial reinforcement (S +/-), A + C- training resulted in a preference for B over D, whereas B + D- training resulted in a preference for A over C. Thus, simultaneous discrimination training appears to result in bidirectional within-event conditioning involving the S+ and S-.