Zentall, T. R., Roper, K. L., & Sherburne, L. M. (1995). Most directed forgetting in pigeons can be attributed to the absence of reinforcement on forget trials during training or to other procedural artifacts. J Exp Anal Behav, 63(2), 127–137.
Abstract: In research on directed forgetting in pigeons using delayed matching procedures, remember cues, presented in the delay interval between sample and comparisons, have been followed by comparisons (i.e., a memory test), whereas forget cues have been followed by one of a number of different sample-independent events. The source of directed forgetting in delayed matching to sample in pigeons was examined in a 2 x 2 design by independently manipulating whether or not forget-cue trials in training ended with reinforcement and whether or not forget-cue trials in training included a simultaneous discrimination (involving stimuli other than those used in the matching task). Results were consistent with the hypothesis that reinforced responding following forget cues is sufficient to eliminate performance deficits on forget-cue probe trials. Only when reinforcement was omitted on forget-cue trials in training (whether a discrimination was required or not) was there a decrement in accuracy on forget-cue probe trials. When reinforcement is present, however, the pattern of responding established during and following a forget cue in training may also play a role in the directed forgetting effect. These findings support the view that much of the evidence for directed forgetting using matching procedures may result from motivational and behavioral artifacts rather than the loss of memory.
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Boysen, S. T., & Berntson, G. G. (1995). Responses to quantity: perceptual versus cognitive mechanisms in chimpanzees (Pan troglodytes). J Exp Psychol Anim Behav Process, 21(1), 82–86.
Abstract: Two chimpanzees were trained to select among 2 different amounts of candy (1-6 items). The task was designed so that selection of either array by the active (selector) chimpanzee resulted in that array being given to the passive (observer) animal, with the remaining (nonselected) array going to the selector. Neither animal was able to select consistently the smaller array, which would reap the larger reward. Rather, both animals preferentially selected the larger array, thereby receiving the smaller number of reinforcers. When Arabic numerals were substituted for the food arrays, however, the selector animal evidenced more optimal performance, immediately selecting the smaller numeral and thus receiving the larger reward. These findings suggest that a basic predisposition to respond to the perceptual-motivational features of incentive stimuli can interfere with task performance and that this interference can be overridden when abstract symbols serve as choice stimuli.
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Ishida, N., Oyunsuren, T., Mashima, S., Mukoyama, H., & Saitou, N. (1995). Mitochondrial DNA sequences of various species of the genus Equus with special reference to the phylogenetic relationship between Przewalskii's wild horse and domestic horse. J Mol Evol, 41(2), 180–188.
Abstract: The noncoding region between tRNAPro and the large conserved sequence block is the most variable region in the mammalian mitochondrial DNA D-loop region. This variable region (ca. 270 bp) of four species of Equus, including Mongolian and Japanese native domestic horses as well as Przewalskii's (or Mongolian) wild horse, were sequenced. These data were compared with our recently published Thoroughbred horse mitochondrial DNA sequences. The evolutionary rate of this region among the four species of Equus was estimated to be 2-4 x 10(-8) per site per year. Phylogenetic trees of Equus species demonstrate that Przewalskii's wild horse is within the genetic variation among the domestic horse. This suggests that the chromosome number change (probably increase) of the Przewalskii's wild horse occurred rather recently.
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Pere, M. C. (1995). Maternal and fetal blood levels of glucose, lactate, fructose, and insulin in the conscious pig. J. Anim Sci., 73(10), 2994–2999.
Abstract: To study nutrition and metabolism in the fetal pig, a chronic catheterization method was developed that allows blood sampling in arteries and veins, at both the umbilical and uterine sources, in the conscious, unstressed animal. A catheter was inserted in the fetal aorta through a femoral artery, and another one was introduced in the umbilical vein. A catheter was put in a femoral artery of the sow so that its end was in the abdominal aorta. A fourth catheter was placed in a uterine vein draining the fetoplacental unit studied. This procedure was applied to 18 Large White primiparous sows at 99 d of gestation. Blood samples were drawn simultaneously using the four catheters before a meal at 103 d of pregnancy, and glucose, insulin, lactate, and fructose were determinated. Glycemia was 2.5 times higher in the sow than in the fetus. The extraction coefficient of glucose by the fetus amounted to 14% of the umbilical supply. The insulin level in the fetal pig was very low ( < 5 microU/mL). Lactate and fructose seemed to originate from the placenta. Blood lactate was 2.6 times lower in the sow than in the fetus, and its extraction coefficient by the fetus amounted to 8%. Fructose in the fetal blood was 2.3 times higher than that of glucose. Fructose was not utilized by the pig fetus. The present results obtained in the fetal pig are comparable to the conclusions drawn from studies with other species.
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Swanson, J. C. (1995). Farm animal well-being and intensive production systems. J. Anim Sci., 73(9), 2744–2751.
Abstract: Animal welfare, or well-being, is a social issue with ethical, scientific, political, and aesthetic properties. Answering questions about the welfare of animals requires scientific definition, assessment, solutions, and public acceptance. With respect to the actual well-being of the animal, most issues are centered on how the animal “feels” when managed within a specific level of confinement, during special agricultural practices (e.g., tail docking, beak trimming, etc.) and handling. Questions of this nature may require exploration of animal cognition, motivation, perception, and emotional states in addition to more commonly recognized indicators of well-being. Several general approaches have emerged for solving problems concerning animal well-being in intensive production systems: environmental, genetic, and therapeutic. Environmental approaches involve modifying existing systems to accommodate specific welfare concerns or development of alternative systems. Genetic approaches involve changing the behavioral and (or) physiological nature of the animal to reduce or eliminate behaviors that are undesirable within intensive system. Therapeutic approaches of a physical (tail docking, beak trimming) and physiological (drug and nutritional therapy) nature bring both concern and promise with regard to the reduction of confinement stress. Finally, the recent focus on commodity quality assurance programs may indirectly provide benefits for animal well-being. Although research in the area of animal well-being will provide important information for better animal management, handling, care, and the physical design of intensive production systems there is still some uncertainty regarding public acceptance. The aesthetics of modern intensive production systems may have as much to do with public acceptance as with science.
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Call, J., & Tomasello, M. (1995). Use of social information in the problem solving of orangutans (<em>Pongo pygmaeus</em>) and human children (<em>Homo sapiens</em>). J. Comp. Psychol., 109(3), 308–320.
Abstract: Fourteen juvenile and adult orangutans and 24 3- and 4-yr-old children participated in 4 studies on imitative learning in a problem-solving situation. In all studies a simple to operate apparatus was used, but its internal mechanism was hidden from subjects to prevent individual learning. In the 1st study, orangutans observed a human demonstrator perform 1 of 4 actions on the apparatus and obtain a reward; they subsequently showed no signs of imitative learning. Similar results were obtained in a 2nd study in which orangutan demonstrators were used. Similar results were also obtained in a 3rd study in which a human encouraged imitation from an orangutan that had previously been taught to mimic arbitrary human actions. In a 4th study, human 3- and 4-yr-old children learned the task by means of imitation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)
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Russon, A. E., & Galdikas, B. M. F. (1995). Constraints on great apes' imitation: Model and action selectivity in rehabilitant orangutan (Pongo pygmaeus) imitation. J. Comp. Psychol., 109(1), 5–17.
Abstract: We discuss selectivity in great ape imitation, on the basis of an observational study of spontaneous imitation in free-ranging rehabilitant orangutans (Pongo pygmaeus). Research on great ape imitation has neglected selectivity, although comparative evidence suggests it may be important. We observed orangutans in central Indonesian Borneo and assessed patterns in the models and actions they spontaneously imitated. The patterns we found resembled those reported in humans. Orangutans preferred models with whom they had positive affective relationships (e.g., important caregiver or older sibling) and actions that reflected their current competence, were receptively familiar, and were relevant to tasks that faced them. Both developmental and individual variability were found. We discuss the probable functions of imitation for great apes and the role of selectivity in directing it. We also make suggestions for more effective elicitation of imitation. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
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Kasuya, E. (1995). A randomization test for linearity of dominance hierarchies. J. Ethol., 13(1), 137–140.
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Dugatkin, L. A., & Hoglund, J. (1995). Delayed breeding and the evolution of mate copying in lekking species. J. Theor. Biol., 174(3), 261–267.
Abstract: Recent experimental evidence indicates that females may copy the mate choice of others. Here, we present a model for the evolution of mate copying strategies in lekking species. In the model, all females (copiers and non-copiers) assess male quality, but a copier's assessment of a male's quality increases after males have mated with other females. The model demonstrates that mate copying is favored when breeding late in the season has a relatively high cost. We hope that our results will spur empirical work quantifying the time constraints associated with breeding, thus allowing more direct tests of the model's predictions.
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Marinier, S. L., & Alexander, A. J. (1995). Coprophagy as an avenue for foals of the domestic horse to learn food preferences from their dams. J. Theor. Biol., 173(2), 121–124.
Abstract: Observation of foal development shows that the appearance of adult-type motor grazing behaviour, selection of grass vs. non-grass and the avoidance of poisonous plants occur concurrently between the ages of 4 and 6 weeks. Suckling behaviour and close association of foal with dam change with time but show no particular coincidence with grazing behavioural changes. Coprophagy of the foal on maternal faeces does, however, correspond chronologically with the foal learning to graze selectively. This correspondence suggests that, as well as other uses, in domestic horses coprophagy may function to imprint on the foal the food-selective values of its dam.
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