Poling, A., Temple, W., & Foster, T. M. (1996). The differential outcomes effect: A demonstration in domestic chickens responding under a titrating-delayed-matching-to-sample procedure. Behav. Process., 36(2), 109–115.
Abstract: The differential outcomes effect refers to the increase in speed of acquisition or terminal accuracy that occurs in discrimination training when each of two or more discriminative stimuli is correlated with a different outcome (e.g. type of reinforcer). The present study demonstrated this effect in domestic hens exposed to a titrating-delayed-matching-to-sample procedure, under which correct responses increased (and incorrect responses decreased) the delay between the offset of a sample stimulus and the onset of two comparison stimuli. Colors of key illumination (red, green) were used as sample and comparison stimuli and correct responses resulted in 1- or 4-s food deliveries. When 1-s food deliveries consistently followed correct responses to one key color and 4-s food deliveries followed correct responses to the other key color, the maximum delay reached by the hens and their overall accuracy was significantly higher than when 1- and 4-s food deliveries were randomly arranged following correct responses to both key colors. These data constitute the first demonstration of the differential outcomes effect in chickens, and in any species evaluated under a titrating-delayed-matching-to-sample procedure.
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Mal, M. E., & McCall, C. A. (1996). The influence of handling during different ages on a halter training test in foals. Appl. Anim. Behav. Sci., 5(2), 115–120.
Abstract: Ten foals were used to determine effects of handling during different ages on their ability to perform a halter training test. Early-handled (EH) foals (n = 5) were handled in 10 min sessions 5 d weekly from 24 h after birth until 42 d of age, then were not handled from 43 to 84 d of age. Later-handled (LH) foals (n = 5) were not handled from birth to 42 d of age, then were handled in 10-min sessions 5 d weekly from 43 to 84 d of age. At 85 d of age, each foal was subjected to a 10 min halter training test for 5 consecutive d. The test consisted of an unfamiliar handler placing a halter on each foal and attempting to make the foal walk forward for 20 m. Data recorded during each d of the halter training were duration of initial struggle, number of lunges into the air, time to first forward step, time to five consecutive forward steps, and time to travel 20 m. At the end of the 5 d halter training test, the handler assigned a subjective test rating score to each foal based on ease of training. Split-plot analysis indicated that EH foals took less time (P < 0.05) to take one step forward, five consecutive steps forward, and to travel 20 m than LH foals. One-way ANOVA indicated that EH foals had a lower (more desirable) test ratings than LH foals (P < 0.01). Results indicate that handling throughout the first 42 d of life increased foal performance on this halter training task compared to handling from 43 to 84 d of age. These results may imply the existence of a critical handling period during the first 42 d of age or a phenomenon similar to learned helplessness
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Brückner, P. D. med. R. (1996). Dein Pferd, sein Auge, seine Sehweise. Basel: Selbstverlag.
Abstract: Inhalt u.a.: Das Pferdeauge, Sehorgan eines Weidegängers. Das Gesichtsfeld. Hornhaut und Pupille. Bewegungen des Augenpaares. Die Zusammenkoppelung der Augen. Sehschärfe. Scharfeinstellung des Auges für die Nähe. Stereopsis (“dreidimensionales” Sehen). Verhalten bei Blindheit mit verbundenen Augen. Augenkrankheiten bei Pferden. Überprüfung der Gesundheit des Pferdeauges.
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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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