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Tang, A. C., Reeb, B. C., Romeo, R. D., & McEwen, B. S. (2003). Modification of Social Memory, Hypothalamic-Pituitary-Adrenal Axis, and Brain Asymmetry by Neonatal Novelty Exposure. The Journal of Neuroscience, 23(23), 8254–8260.
Abstract: Although corticosterone (a stress hormone) is known to influence social behavior and memory processes, little has been explored concerning its modulatory role in social recognition. In rats, social recognition memory for conspecifics typically lasts <2 hr when evaluated using a habituation paradigm. Using neonatal novelty exposure, a brief and transient early life stimulation method known to produce long-lasting changes in the hypothalamic-pituitary-adrenal axis, we found that social recognition memory was prolonged to at least 24 hr during adulthood. This prolonged social memory was paralleled by a reduction in the basal blood concentration of corticosterone. The same neonatal stimulation also resulted in a functional asymmetry expressed as a greater right-turn preference in a novel environment. Rats that preferred to turn right showed better social recognition memory. These inter-related changes in basal blood corticosterone concentration, turning asymmetry, and social recognition memory suggest that stress hormones and brain asymmetry are likely candidates for modulating social memory. Furthermore, given that neonatal stimulation has been shown to improve learning and memory performance primarily under aversive learning situations, the neonatal novelty exposure-induced enhancement in social recognition broadens the impact of early life stimulation to include the social domain.
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Albentosa, M. J., Kjaer, J. B., & Nicol, C. J. (2003). Strain and age differences in behaviour, fear response and pecking tendency in laying hens. Br Poult Sci, 44(3), 333–344.
Abstract: 1. Behaviours associated with a high or low tendency to feather peck could be used as predictors of feather pecking behaviour in selective breeding programmes. This study investigated how strain and age at testing influenced responses in behavioural tests. 2. Four layer-type strains (ISA Brown, Columbian Blacktail, Ixworth and a high feather pecking (HP) and a low feather pecking (LP) line of White Leghorn) were reared in 6 same-strain/line pens of 8 birds from one day old. Birds in half the pens were given an open field test, a novel object test and a test with loose feather bundles between 4 and 12 weeks of age and a tonic immobility (TI) test at 13 weeks of age. All pens were tested with fixed feather bundles at 26 weeks, and undisturbed behaviour in the home pens was videoed at 1 and 27 weeks of age. Daily records of plumage damage were used as an indicator of feather pecking activity in the home pens. 3. Strain did not influence novel object test, open field test or loose feather test behaviour, although age effects in all three tests indicated a reduction in fearfulness and/or an increase in exploratory behaviour with increasing age. 4. White Leghorns showed longer TI durations than the other strains but less pecking at fixed feather bundles than ISA Browns and Columbian Blacktails. 5. There were few associations between behaviour in the 5 different tests, indicating that birds did not have overall behavioural traits that were consistent across different contexts. This suggests hens cannot easily be categorised into different behavioural 'types', based on their test responses and casts doubt on the usefulness of tests as predictors of feather pecking.
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Sole, L. M., Shettleworth, S. J., & Bennett, P. J. (2003). Uncertainty in pigeons. Psychon Bull Rev, 10(3), 738–745.
Abstract: Pigeons classified a display of illuminated pixels on a touchscreen as sparse or dense. Correct responses were reinforced with six food pellets; incorrect responses were unreinforced. On some trials an uncertain response option was available. Pecking it was always reinforced with an intermediate number of pellets. Like monkeys and people in related experiments, the birds chose the uncertain response most often when the stimulus presented was difficult to classify correctly, but in other respects their behavior was not functionally similar to human behavior based on conscious uncertainty or to the behavior of monkeys in comparable experiments. Our data were well described by a signal detection model that assumed that the birds were maximizing perceived reward in a consistent way across all the experimental conditions.
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Cooper, J. J., Ashton, C., Bishop, S., West, R., Mills, D. S., & Young, R. J. (2003). Clever hounds: social cognition in the domestic dog (Canis familiaris). Appl. Anim. Behav. Sci., 81(3), 229–244.
Abstract: This paper reviews the reasons why domestic dogs make good models to investigate cognitive processes related to social living and describes experimental approaches that can be adopted to investigate such processes in dogs. Domestic dogs are suitable models for investigating social cognition skills for three broad reasons. First, dogs originated from wolves, social animals that engage in a number of co-operative behaviours, such as hunting and that may have evolved cognitive abilities that help them predict and interpret the actions of other animals. Second, during domestication dogs are likely to have been selected for mental adaptations for their roles in human society such as herding or companionship. Third, domestic dogs live in a human world and “enculturation” may facilitate the development of relevant mental skills in dogs. Studies of social cognition in animals commonly use experimental paradigms originally developed for pre-verbal human infants. Preferential gaze, for example, can be used as a measure of attention or “surprise” in studies using expectancy violation. This approach has been used to demonstrate simple numerical competence in dogs. Dogs also readily use both conspecific and human social signals (e.g. looking or pointing) as information sources to locate hidden rewards such as food or favourite toys. Such abilities make dogs particularly good models for investigating perspective-taking tasks, where animals are required to discriminate between apparently knowledgeable and apparently ignorant informants.
Keywords: Domestic dog; Canine; Social cognition; Counting; Theory of mind; Perspective taking
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Hanggi, E. B. (2003). Discrimination learning based on relative size concepts in horses (Equus caballus). Appl. Anim. Behav. Sci., 83(3), 201–213.
Abstract: This study explored whether or not horses (Equus caballus) could respond to stimuli using a concept based on relative size. In Experiment 1, after learning to respond to the larger of the two stimuli for six sets of two-dimensional (2D) training exemplars, one horse was tested for size transposition that used novel larger and smaller stimuli as well as three-dimensional (3D) objects (5 two-dimensional sets and 5 three-dimensional sets with large, medium, small, and tiny sizes). The horse correctly chose (significantly above chance) the larger of two stimuli regardless of novelty or dimension or combination. In Experiment 2, two additional horses were tested using a subset of the stimuli from Experiment 1. One horse was required to select the larger stimulus--as in Experiment 1--and the other the smaller stimulus. After learning the task, both horses responded correctly to new stimuli and showed size transposition. These results suggest that at least some horses are capable of solving problems based on relative size concepts. Moreover, they are able to generalize across situations that vary from flat, black shapes to objects of different materials and colors including balls, flower pots, and PVC connectors. These findings support earlier research that showed that horses could categorize certain stimuli, and provide new evidence that they are capable of using some form of concept for problem solving. Understanding that horses have more advanced learning abilities than was previously believed should help improve training methods and management.
Keywords: Horse; Concept; Size transposition; Generalization; Learning; Training
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Bond, A. B., Kamil, A. C., & Balda, R. P. (2003). Social complexity and transitive inference in corvids. Anim. Behav., 65(3), 479–487.
Abstract: The social complexity hypothesis asserts that animals living in large social groups should display enhanced cognitive abilities along predictable dimensions. To test this concept, we compared highly social pinyon jays,Gymnorhinus cyanocephalus , with relatively nonsocial western scrub-jays, Aphelocoma californica, on two complex cognitive tasks relevant to the ability to track and assess social relationships. Pinyon jays learned to track multiple dyadic relationships more rapidly and more accurately than scrub-jays and appeared to display a more robust and accurate mechanism of transitive inference. These results provide a clear demonstration of the association between social complexity and cognition in animals. Copyright 2003 Published by Elsevier Science Ltd on behalf of The Association for the Study of Animal Behaviour.
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Gammell, M. P., de Vries, H., Jennings, D. J., Carlin, C. M., & Hayden, T. J. (2003). David's score: a more appropriate dominance ranking method than Clutton-Brock et al.'s index. Anim. Behav., 66(3), 601–605.
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Dugatkin, L. A., & Bekoff, M. (2003). Play and the evolution of fairness: a game theory model. Behav. Process., 60(3), 209–214.
Abstract: Bekoff [J. Consci. Stud. 8 (2001) 81] argued that mammalian social play is a useful behavioral phenotype on which to concentrate in order to learn more about the evolution of fairness. Here, we build a game theoretical model designed to formalize some of the ideas laid out by Bekoff, and to examine whether `fair' strategies can in fact be evolutionarily stable. The models we present examine fairness at two different developmental stages during an individual's ontogeny, and hence we create four strategies--fair at time 1/fair at time 2, not fair at time 1/not fair at time 2, fair at time 1/not fair at time 2, not fair at time 1/fair at time 2. Our results suggest that when considering species where fairness can be expressed during two different developmental stages, acting fairly should be more common than never acting fairly. In addition, when no one strategy was evolutionarily stable, we found that all four strategies we model can coexist at evolutionary equilibrium. Even in the absence of an overwhelming database from which to test our model, the general predictions we make have significant implications for the evolution of fairness.
Keywords: Play; Fairness; Game theory
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Dugatkin, L. A., & Earley, R. L. (2003). Group fusion: the impact of winner, loser, and bystander effects on hierarchy formation in large groups. Behav. Ecol., 14(3), 367–373.
Abstract: We present the results of a series of computer simulations that examined the impact of winner, loser, and bystander effects on hierarchy formation in fused groups. These effects and their implications for hierarchy structure and aggressive interactions were first examined in small four-member groups. Subsequent to this, the two small groups were fused into a single larger group. Further interactions took place in this fused group, generating a new hierarchy. Our models demonstrate clearly that winner, loser, and bystander effects strongly influence both the structure and types of interactions that emerge from the fusion of smaller groups. Four conditions produced results in which the same general patterns were uncovered in pre- and postfusion groups: (1) winner effects alone, (2) bystander loser effects alone, (3) winner and bystander winner effects operating simultaneously, and (4) all four effects in play simultaneously. Outside this parameter space, hierarchy structure and the nature of aggressive interactions differed in pre- and postfusion groups. When only loser effects were in play, one of the two clear alphas from the prefused groups dropped in rank in the eight-member fused group. When bystander winner effects were in play, it was difficult to rank any of the eight individuals in the fused group, and players interacted almost exclusively with those that were not in their original four-member group. When loser and bystander loser effects operated simultaneously, two top-ranking individuals emerged in the fused groups, but the relative rank of the other players was difficult to assign.
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Pongrácz, P., Miklósi, Á., Kubinyi, E., Topál, J., & Csányi, V. (2003). Interaction between individual experience and social learning in dogs. Anim. Behav., 65(3), 595–603.
Abstract: We investigated the interaction between individual experience and social learning in domestic dogs,Canis familiaris . We conducted two experiments using detour tests, where an object or food was placed behind a transparent, V-shaped wire-mesh fence, such that the dogs could get the reward by going around the fence. In some groups, two open doors were offered as an alternative, easier way to reach the reward. In experiment 1 we opened the doors only in trial 1, then closed them for trials 2 and 3. In experiment 2 other dogs were first taught to detour the fence with closed doors after they had observed a detouring human demonstrator, then we opened the doors for three subsequent trials. In experiment 1 all dogs reached the reward by going through the doors in trial 1, but their detouring performance was poor after the doors had been closed, if they had to solve the task on their own. However, dogs in the experimental group that were allowed to watch a detouring human demonstrator after the doors had been closed showed improved detouring ability compared with those that did not receive a demonstration of detouring. In experiment 2 the dogs tended to keep on detouring along the fence even if the doors had been opened, giving up a chance to get behind the fence by a shorter route. These results show that dogs can use information gained by observing a human demonstrator to overcome their own mistakenly preferred solution in a problem situation. In a reversed situation social learning can also contribute to a preference for a less adaptive behaviour. However, only repeated individual and social experience leads to a durable manifestation of maladaptive behaviour. Copyright 2003 Published by Elsevier Science Ltd on behalf of The Association for the Study of Animal Behaviour.
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