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Lensink, J., Veissier, I., & Boissy, A. (2006). Enhancement of performances in a learning task in suckler calves after weaning and relocation: Motivational versus cognitive control?: A pilot study. Appl. Anim. Behav. Sci., 100(3-4), 171–181.
Abstract: Weaning in suckler calves influences performance in a learning task. The aim of the present study was to investigate whether the improved performance after weaning, including relocation, is due to differences in motivation for the reward or in learning abilities. Forty Aubrac calves were used; half of them were weaned from their dams at around eight months, the other half were weaned one month later. After weaning, calves were housed in groups of four in a new setting. From the day after weaning of the last group of calves, the animals were subjected to two tests: (1) an arena test, (2) a T-maze test where one arm led to either a social or a food reward. The T-maze test consisted of three sessions: in Session 1, trials were conducted until the animal acquired the task (i.e. did not take the unrewarded arm on three consecutive trials); in Session 2, the motivation for the reward was assessed via the walking time of the animal to reach the reward; in Session 3, the place of reward was reversed and the animals were trained until they acquired the new task. Calves weaned for one day explored more (P < 0.05) and had lower heart rates during the arena test (P < 0.05) compared to the ones weaned for one month. During the T-maze test, calves weaned for one month versus one day did not differ in their capacities to learn the initial route (Session 1) or in their motivation for either the social or food reward (Session 2). Calves weaned for one day learned significantly faster (P < 0.05) the reversed route (Session 3) than calves weaned for one month. Hence, the better performances at reversal in the T-maze by calves that have just been weaned cannot be accounted for by a higher motivation for the reward. A better cognitive control of their behaviour due to a lower stress state is suggested by our results.
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Levy, F., Keller, M., & Poindron, P. (2004). Olfactory regulation of maternal behavior in mammals. Horm Behav, 46(3), 284–302.
Abstract: In mammals, olfactory cues are extensively used in many aspects of maternal care to ensure the coordination of mother-infant interactions and consequently the normal development of the offspring. Outside the period of parturition and lactation, when the young are not a behavioral priority, olfactory cues play an inhibitory role on maternal responsiveness since in most mammalian species studied so far, nonpregnant females find the odor of young aversive. On the contrary at the time of parturition, a shift in the hedonic value of infantile odors occurs so that the young now become a very potent stimulus and this sensorial processing constitutes an important part of the maternal motivational system. Moreover, infants' odors provide a basis for individual recognition by their mothers and some species (ungulates) have developed highly specialized mechanisms for processing of the infant signals. Perception of the smell of the young also regulates various aspects of maternal behavior. Dodecyl propionate, a compound released by of pup's preputial glands, has been shown to influence anogenital licking behavior, a fundamental pattern of maternal behavior in rodents. While there is no functional specificity of either the main or the accessory olfactory systems in the development of maternal behavior amongst species, it appears that only the main olfactory system is implicated when individual odor discrimination of the young is required. Neural structures, such as the main olfactory bulb, undergo profound changes when exposed to offspring odors at parturition. These changes in synaptic circuitry contribute both to maternal responsiveness to these odors, to their memorization, and to effects of long-term maternal experience.
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Levy, J. (1977). The mammalian brain and the adaptive advantage of cerebral asymmetry. Ann N Y Acad Sci, 299, 264–272.
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Liebal, K., Pika, S., & Tomasello, M. (2004). Social communication in siamangs (Symphalangus syndactylus): use of gestures and facial expressions. Primates, 45(1), 41–57.
Abstract: The current study represents the first systematic investigation of the social communication of captive siamangs (Symphalangus syndactylus). The focus was on intentional signals, including tactile and visual gestures, as well as facial expressions and actions. Fourteen individuals from different groups were observed and the signals used by individuals were recorded. Thirty-one different signals, consisting of 12 tactile gestures, 8 visual gestures, 7 actions, and 4 facial expressions, were observed, with tactile gestures and facial expressions appearing most frequently. The range of the signal repertoire increased steadily until the age of six, but declined afterwards in adults. The proportions of the different signal categories used within communicative interactions, in particular actions and facial expressions, also varied depending on age. Group differences could be traced back mainly to social factors or housing conditions. Differences in the repertoire of males and females were most obvious in the sexual context. Overall, most signals were used flexibly, with the majority performed in three or more social contexts and almost one-third of signals used in combination with other signals. Siamangs also adjusted their signals appropriately for the recipient, for example, using visual signals most often when the recipient was already attending (audience effects). These observations are discussed in the context of siamang ecology, social structure, and cognition.
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Ligout, S., Porter, R. H., & Bon, R. (2002). Social discrimination in lambs: persistence and scope. Appl. Anim. Behav. Sci., 76(3), 239–248.
Abstract: Social recognition among familiar unrelated lambs was assessed in a series of tests. Lambs and their mothers were housed together in small groups for 1 week (Original groups; O) then reorganized into new groupings (Recent-groups; R) for the remainder of the experiment. During test series 1, lambs that were paired with a familiar O-group partner, from which they had been separated for 5 days, emitted fewer distress bleats than did those tested with an unfamiliar partner. This same effect was not evident when the test was repeated several hours later, indicating that the animals had become habituated to the testing procedures. Two days later, when given the choice between an O- versus a R-partner (test series 2), lambs did not display a preference for either of the stimulus lambs. However, in an additional two-choice test (test series 3) the subject lambs responded discriminatively to a recent familiar partner that was simultaneously present with an unfamiliar lamb. Overall, the results suggest that lambs are capable of developing discriminative relationships with age-mates from different sub-groups, and that such social discrimination persists over a separation period lasting at least several days. It is not clear whether lambs recognize several individual conspecifics per se or discriminate between members of higher order social categories (e.g. familiar versus unfamiliar individuals). Proximal and distal social discrimination may be mediated by different combinations of sensory modalities.
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Lim, M. M., & Young, L. J. (2006). Neuropeptidergic regulation of affiliative behavior and social bonding in animals. Hormon. Behav., 50(4), 506–517.
Abstract: Social relationships are essential for maintaining human mental health, yet little is known about the brain mechanisms involved in the development and maintenance of social bonds. Animal models are powerful tools for investigating the neurobiological mechanisms regulating the cognitive processes leading to the development of social relationships and for potentially extending our understanding of the human condition. In this review, we discuss the roles of the neuropeptides oxytocin and vasopressin in the regulation of social bonding as well as related social behaviors which culminate in the formation of social relationships in animal models. The formation of social bonds is a hierarchical process involving social motivation and approach, the processing of social stimuli and formation of social memories, and the social attachment itself. Oxytocin and vasopressin have been implicated in each of these processes. Specifically, these peptides facilitate social affiliation and parental nurturing behavior, are essential for social recognition in rodents, and are involved in the formation of selective mother-infant bonds in sheep and pair bonds in monogamous voles. The convergence of evidence from these animal studies makes oxytocin and vasopressin attractive candidates for the neural modulation of human social relationships as well as potential therapeutic targets for the treatment of psychiatric disorders associated with disruptions in social behavior, including autism.
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Lingle, S., Rendall, D., & Pellis, S. M. (2007). Altruism and recognition in the antipredator defence of deer: 1. Species and individual variation in fawn distress calls. Anim. Behav., 73(5), 897–905.
Abstract: Mule deer, Odocoileus hemionus, females actively defend fawns against predators, including nonoffspring conspecific fawns and heterospecific white-tailed deer, O. virginianus, fawns. We hypothesized that the defence of nonoffspring fawns was due to a recognition error. During a predator attack, females may have to decide whether to defend a fawn with imperfect information on its identity obtained from hearing only a few distress calls. We examined fawn distress calls to determine whether calls made by the two species and by different individuals within each species were acoustically distinctive. The mean and maximum fundamental frequencies of mule deer fawns were nearly double those of white-tailed deer fawns, with no overlap, enabling us to classify 100% of calls to the correct species using a single trait. A large proportion of calls was also assigned to the correct individual using a multivariate analysis (66% and 70% of mule deer and white-tailed deer fawns, respectively, chance = 6% and 10%); however, there was considerable statistical uncertainty in the probability of correct classification. We observed fawns approach conspecific females in an attempt to nurse; females probed most offspring fawns with their noses before accepting them, and always probed nonoffspring fawns before rejecting them, suggesting that close contact and olfactory information were needed to unequivocally distinguish nonoffspring from offspring fawns. Taken together, these results suggest that acoustic variation alone would probably be sufficient to permit rapid and reliable species discrimination, but it may not be sufficient for mothers to unequivocally distinguish their own fawn from conspecific fawns.
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Lingle, S., Rendall, D., Wilson, W. F., DeYoung, R. W., & Pellis, S. M. (2007). Altruism and recognition in the antipredator defence of deer: 2. Why mule deer help nonoffspring fawns. Anim. Behav., 73(5), 907–916.
Abstract: Both white-tailed deer, Odocoileus virginianus, and mule deer, O. hemionus, females defend fawns against coyotes, Canis latrans, but only mule deer defend nonoffspring conspecific and heterospecific fawns. During a predator attack, females may have to decide whether to defend a fawn while having imperfect information on its identity obtained from hearing a few distress calls. Although imperfect recognition can influence altruistic behaviour, few empirical studies have considered this point when testing functional explanations for altruism. We designed a series of playback experiments with fawn distress calls to test alternative hypotheses (by-product of parental care, kin selection, reciprocal altruism) for the mule deer's defence of nonoffspring, specifically allowing for the possibility that females mistake these fawns for their own. White-tailed deer females approached the speaker only when distress calls of white-tailed deer fawns were played and when their own fawn was hidden, suggesting that fawn defence was strictly a matter of parental care in this species. In contrast, mule deer females responded similarly and strongly, regardless of the caller's identity, the female's reproductive state (mother or nonmother) or the presence of their own offspring. The failure of mule deer females to adjust their responses to these conditions suggests that they do not defend nonoffspring because they mistake them for their own fawns. The lack of behavioural discrimination also suggests that kin selection, reciprocal altruism and defence of the offspring's area are unlikely to explain the mule deer's defence of nonoffspring. We identify causal and functional questions that still need to be addressed to understand why mule deer defend fawns so indiscriminately.
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Linton, M. L. (1970). Washoe the chimpanzee. Science, 169(943), 328.
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Lonon, A. M., & Zentall, T. R. (1999). Transfer of value from S+ to S- in simultaneous discriminations in humans. Am J Psychol, 112(1), 21–39.
Abstract: When animals learn a simultaneous discrimination, some of the value of the positive stimulus (S+) appears to transfer to the negative stimulus (S-). The present experiments demonstrate that such value transfer can also be found in humans. In Experiment 1 humans were trained on 2 simple simultaneous discriminations, the first between a highly positive stimulus, A (1,000 points); and a negative stimulus, B (0 points); and the second between a less positive stimulus, C (100 points); and a negative stimulus, D (0 points). On test trials, most participants preferred B over D. In Experiments 2 and 3 the value of the 2 original discriminations was equated in training (A[100]B[0] and C[100]D[0]). In Experiment 2 the values of the positive stimuli were then altered (A[1,000]C[0]); again, most participants preferred B over D. In Experiment 3, however, when the values of B and D were altered (B[1,000]D[0]), participants were indifferent to A and C. Thus, the mechanism that underlies value transfer in humans appears to be related to Pavlovian second-order conditioning. Similar mechanisms may be involved in assimilation processes in social contexts.
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