Palme, R., Fischer, P., Schildorfer, H., & Ismail, M. N. (1996). Excretion of infused 14C-steroid hormones via faeces and urine in domestic livestock. Animal Reproduction Science, 43(1), 43–63.
Abstract: The aim of this comparative study was to gain more information about the excretion of steroid hormones in farm animals. This should help to establish or improve non-invasive steroid monitoring procedures, especially in zoo and wildlife animals. Over a period of 4 h the 14C-steroid hormones (3.7 MBq) progesterone (three females), testosterone (three males), cortisol and oestrone (two males, two females) were infused intravenously in sheep, ponies and pigs. Faeces were collected immediately after defecation. Urine was sampled via a permanent catheter in females and after spontaneous urination in males. A total of 88 +/- 10% (mean +/- SD) of the administered radioactivity was recovered. Considerable interspecies differences were measured both in the amounts of steroid metabolites excreted via faeces or urine and the time course of excretion. Progesterone and oestrone in ewes, and progesterone in mares were excreted mainly in the faeces (over 75%). The primary route of excretion of all other 14C-steroids was via the urine but to a different extent. In general, sheep showed the highest degree of faecal excretion and pigs the least. The highest radioactivity in urine (per mmol creatinine) was observed during the infusion or in one of the next two samples thereafter, whereas in faeces it was measured about 12 h (sheep), 24 h (ponies) or 48 h (pigs) after the end of the infusion. Thereafter the radioactivity declined and reached background levels within 2-3 weeks. In faeces, steroid metabolites were present mainly in an unconjugated form, but in blood and urine as conjugates. Mean retention time of faecal radioactivity suggested that the passage rate of digesta (duodenum to rectum) played an important role in the time course of the excretion of steroids. The information derived from this investigation could improve the precision of sampling as well as the extraction of steroids from the faeces. Furthermore, the study demonstrates that it should be possible to establish methods for measuring faecal androgen and cortisol metabolites for assessing male reproductive endocrinology and stress in animals.
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Laland, K. N., Richerson, P. J., & Boyd, R. (1996). Developing a theory of animal social learning. In C. M. Heyes, & B. G. J. Galef (Eds.), Social learning in animals: the roots of culture. (pp. 129–154). San Diego, California: Academic Press.
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Boyd, R., & Richerson, P. J. (1996). Why Culture is Common, but Cultural Evolution is Rare. Proc Br Acad, 88, 73–93.
Abstract: If culture is defined as variation acquired and maintained by social learning, then culture is common in nature. However, cumulative cultural evolution resulting in behaviors that no individual could invent on their own is limited to humans, song birds, and perhaps chimpanzees. Circumstantial evidence suggests that cumulative cultural evolution requires the capacity for observational learning. Here, we analyze two models the evolution of psychological capacities that allow cumulative cultural evolution. Both models suggest that the conditions which allow the evolution of such capacities when rare are much more stringent than the conditions which allow the maintenance of the capacities when common. This result follows from the fact that the assumed benefit of the capacities, cumulative cultural adaptation, cannot occur when the capacities are rare. These results suggest why such capacities may be rare in nature.
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Templeton, J. J., & Giraldeau, L. - A. (1996). Vicarious sampling: the use of personal and public information by starlings foraging in a simple patchy environment. Behav. Ecol. Sociobiol., 38(2), 105–114.
Abstract: Group foragers may be able to assess patch quality more efficiently by paying attention to the sampling activities of conspecifics foraging in the same patch. In a previous field experiment, we showed that starlings foraging on patches of hidden food could use the successful foraging activities of others to help them assess patch quality. In order to determine whether a starling could also use another individual's lack of foraging success to assess and depart from empty patches more quickly, we carried out two experimental studies which compared the behaviour of captive starlings sampling artificial patches both when alone and when in pairs. Solitary starlings were first trained to assess patch quality in our experimental two-patch system, and were then tested on an empty patch both alone and with two types of partner bird. One partner sampled very few holes and thus provided a low amount of public information; the other sampled numerous holes and thus provided a high amount of public information. In experiment 1, we found no evidence of vicarious sampling. Subjects sampled a similar number of empty holes when alone as when with the low and high information partners; thus they continued to rely on their own personal information to make their patch departure decisions. In experiment 2, we modified the experimental patches, increasing the ease with which a bird could watch another's sampling activities, and increasing the difficulty of acquiring accurate personal sampling information. This time, subjects apparently did use public information, sampling fewer empty holes before departure when with the high-information partner than when with the low-information partner, and sampling fewer holes when with the low-information partner than when alone. We suggest that the degree to which personal and public information are used is likely to depend both on a forager's ability to remember where it has already sampled and on the type of environment in which foraging takes place.
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Lebelt, D., Schönreiter, S., & Zanella, A. J. (1996). Salivary cortisol in stallions: the relationship with plasma levels, daytime profile and changes in response to semen collection. Pferdeheilkunde, 14(4), 411–414.
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Miller, R. M. (1996). How we can quickly assume the role of horse herd leader: Making horses compliant and willing subjects. Journal of Equine Veterinary Science, 16(1), 4–7.
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Lefebvre, L., & Giraldeau, L. - A. (1996). Is social learning an adaptive specialisation? In C. M. Heyes, & B. G. Galef B. G..Jr. (Eds.), Social learning in animals: The root of culture (pp. 107–128). San Diego: Academic Press.
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Povinelli, D. J., & Eddy T. J. (1996). What Young Chimpanzees Know about Seeing. Chicago: University of Chicago Press.
Abstract: Synopsis
Does a young chimpanzee's gaze subjectively link it to the outside world? Is seeing “about” something to this species? This volume reports the results of fifteen studies conducted with chimpanzees and preschool children. The findings provide little evidence that young chimpanzees understand seeing as a mental event. Even though young chimps spontaneously attend to and follow the visual gaze of others, they simultaneously appear oblivious to the attentional significance of that gaze. This interpretation is consistent with three different possibilities: chimpanzees may experience a delay in psychological development; alternatively, they may possess a different theory of attention, connected subjectively through other behavioral indicators; or the subjective understanding of visual perception may only be present in humans.
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Gallese, V., Fadiga, L., Fogassi, L., & Rizzolatti, G. (1996). Action recognition in the premotor cortex. Brain, 119(2), 593–609.
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.
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Davis, M. H. (1996). Empathy: A Social Psychological Approach. Boulder, CO: Westview Press.
Abstract: Product Description
Empathy has long been a topic of interest to psychologists, but it has been studied in a sometimes bewildering number of ways. In this volume, Mark Davis offers a thorough, evenhanded review of contemporary empathy research, especially work that has been carried out by social and personality psychologists.Davis’ approach is explicitly multidimensional. He draws careful distinctions between situational and dispositional “antecedents” of empathy, cognitive and noncognitive “internal processes,” affective and nonaffective “intrapersonal outcomes,” and the “interpersonal behaviora
l outcomes” that follow. Davis presents a novel organizational model to help classify and interpret previous findings. This book will be of value in advanced undergraduate and graduate courses on altruism, helping, nad moral development.
About the Author
Mark H. Davis is associate professor of psychology at Eckerd College in St. Petersburg, Florida.
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