Bunnell, B., Gore, W., & Perkins, M. (1980). Performance correlates of social behavior and organization: Social rank and reversal learning in crab-eating macaques (M. fascicularis). Primates, 21(3), 376–388.
Abstract: Abstract Seventeen male crab-eating macaques drawn from two captive troops, were tested on a brightness discrimination, reversal learning task. Fourteen of these animals completed ten reversals. It was found that the performance of the three highest ranking animals from each troop, taken together, was poorer than that of the lower ranking animals that were tested. The high ranking animals made more errors before reaching criterion on both initial learning and the reversal problems. Analysis of error patterns revealed that, while the high ranking animals had no more difficulty than the others in withholding their responses to the previously correct stimulus following reversals, they did not adopt the correct strategy as soon as the low ranking animals. The results have been interpreted in terms of a carry-over of a hypothetical factor or factors resulting from pressures created by the ongoing social dynamics involved in establishing and maintaining a given social rank at the time laboratory testing occurred.
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Keiper, R. R., Moss, M., & Zervanos, S. (1980). Daily and seasonal patterns of feral ponies on Assateague Island. In 2nd Conference on Scientific Research in the National Parks.
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Keiper, R. R., & Keenan, M. A. (1980). Nocturnal activity patterns of feral horses. J. Mammal, 61, 116–118.
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Tumova, B. (1980). Equine influenza--a segment in influenza virus ecology. Comp Immunol Microbiol Infect Dis, 3(1-2), 45–59.
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Milouchine, V. N. (1980). The role of WHO in international studies on the ecology of influenza in animals. Comp Immunol Microbiol Infect Dis, 3(1-2), 25–31.
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Rubin, L., Oppegard, C., & Hindz, H. F. (1980). The effect of varying the temporal distribution of conditioning trials on equine learning behavior. J. Anim Sci., 50(6), 1184–1187.
Abstract: Two experiments were conducted to study the effect of varying the temporal distrbution of conditioning sessions on equine learning behavior. In the first experiment, 15 ponies were trained to clear a small hurdle in response to a buzzer in order to avoid a mild electric shock. Three treatments were used. One group received 10 learning trials daily, seven times a week; one group was trained in the same fashion two times a week and one group was trained once a week. The animals conditioned only once a week achieved a high level of performance in significantly fewer sessions than the ones conditioned seven times a week, although elapsed time from start of training to completion was two to three times greater for the former group. The twice-a-week group learned at an intermediate rate. In the second experiment, the ponies were rearranged into three new groups. They were taught to move backward a specific distance in response to a visual cue in order to avoid an electric shock. Again, one group was trained seven times a week, one group was trained two times and one group was trained once a week. As in the first experiment, the animals trained once a week achieved the learning criteria in significantly fewer sessions than those trained seven times a week, but, as in trial 1, elapsed time from start to finish was greater for them. The two times-a-week group learned at a rate in-between the rates of the other two groups.
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De Moraes Ferrari, E. A., & Todorov, J. C. (1980). Concurrent avoidance of shocks by pigeons pecking a key. J Exp Anal Behav., 30(3), 329–333.
Abstract: Three pigeons were studied on concurrent, unsignaled, avoidance schedules in a two-key procedure. Shock-shock intervals were two seconds in both schedules. The response-shock interval on one key was always 22 seconds, while the response-shock interval associated with the other key was varied from 7 to 52 seconds in different experimental conditions. Response rates on the key associated with the varied schedule tended to decrease when the response-shock interval length was increased. Responding on the key associated with the constant schedule was not systematically affected.
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Lewis, P., Gardner, E. T., & Lopatto, D. (1980). Shock-duration reduction as negative reinforcement. Psychol. Rec,, .
Abstract: In 2 experiments, 9 female Sprague-Dawley albino rats were shocked every 30 sec. Before the barpress response, shocks were long (2 sec); for 3 min after a response, shocks were short (0.1, 0.5, or 1 sec). When responding reduced shocks from 2 to 0.1 sec, barpressing was acquired, and the shorter the shocks the more time spent with the short-shock condition in effect. In another procedure, the duration of individual shocks following a response was controlled so that the 1st shock was as long as those before the response (2 sec), but the remaining shocks in the 3-min period were short (0.1 sec). Barpressing was maintained in some Ss and acquired in others showing that, even when delayed, a reduction in shock duration is reinforcing. These findings question the generality of a 2-factor, safety-signal interpretation of negative reinforcement. These results plus others imply that to predict responding in aversive situations it is necessary to integrate, for at least several minutes, the parameters of aversive events that follow a response. (27 ref) (PsycINFO Database Record (c) 2014 APA, all rights reserved)
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Hintz, R. L. (1980). Genetics of performance in the horse. J. Anim Sci., 51(3), 582–594.
Abstract: Criteria used to measure performance, environmental factors that influence performance and estimates of heritability are needed to estimate genetic differences. Published heritability estimates of various measures of performance in the horse are summarized. The average heritability estimates of pulling ability and cutting ability are .25 and .04, respectively. Heritability estimates are .18, .19 and .17 for log of earnings from jumping, 3-day event and dressage performance, respectively. Heritability estimates of performance rates, log of earnings, earnings, handicap weight, best handicap weight, time and best time for the Thoroughbred are .55, .49, .09, .49, .33, .15 and .23, respectively. Heritability estimates of log of earnings, earnings, time and best time for the trotter are .41, .20, .32, and .25, respectively. The heritability estimate of best time for the pacer is .23. The effectiveness of selection will depend on which performance trait is to be improved.
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Jeffcott, L. B., & Dalin, G. (1980). Natural rigaidity of the horse's backbone. Equine Vet J, 12(3), 101–108.
Abstract: The functional anatomy of the thoracolumbar (TL) spine is considered in relation to the horse's ability to perform at speed and to jump. The morphological features quite clearly show the relative inflexibility of the equine back and this was confirmed by some experimental studies. Fresh post mortem specimens from 5 Thoroughbreds were used to estimate the limits of dorsoventral movement of the TL spine from mid-thoracic to the cranial lumbar (T10-L2). The individual spinous processes could be moved a mean 1.1-6.0 mm on maximum ventroflexion and 0.8-3.8 mm on dorsiflexion. The overall flexibility of the back was found to be 53.1 mm. Caudal to the mid-point of the back (T13) there was virtually no lateral or rotatory movement of the spine possible. The pathogenesis of some of the common causes of back trouble are discussed including the so-called vertebral subluxation and its treatment by chiropractic manipulation. From an anatomical viewpoint, this condition appears to be a misnomer and may simply be attributable to muscular imbalance leading to aspastic scoliosis.
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