Russell, C. L., Bard, K. A., & Adamson, L. B. (1997). Social referencing by young chimpanzees (Pan troglodytes). J. Comp. Psychol., 111(2), 185–191.
Abstract: Social referencing is the seeking of information from another individual and the use of that information to evaluate a situation. It is a well-documented ability in human infants but has not been studied experimentally in nonhuman primates. Seventeen young nursery-reared chimpanzees (14 to 41 months old) were observed in a standard social referencing paradigm in which they received happy and fear messages concerning novel objects from a familiar human caregiver. Each chimpanzee looked referentially at their caregiver, and the emotional messages that they received differentially influenced their gaze behavior and avoidance of the novel objects. It is concluded that chimpanzees can acquire information about their complex social and physical environments through social referencing and can use emotional information to alter their own behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)
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Flack, J. C., Jeannotte, L. A., & de Waal, F. B. M. (2004). Play signaling and the perception of social rules by juvenile chimpanzees (Pan troglodytes). J Comp Psychol, 118(2), 149–159.
Abstract: Prescriptive social rules are enforced statistical regularities. The authors investigated whether juvenile chimpanzees (Pan troglodytes) recognize and use enforced statistical regularities to guide dyadic play behavior. They hypothesized (a) that proximity of adults, especially mothers of younger play partners, to play bouts will increase the play signaling of older partners and (b) that when juvenile-juvenile play bouts occur in proximity to adults, older partners will play at a lower intensity than when no adults are present. They found that older and younger partners increase their play signaling in the presence of the mothers of younger partners, particularly as the intensity of play bouts increases. In contrast to their hypothesis, older partners played more roughly when the mothers of younger partners were in proximity. These results suggest that juvenile chimpanzees increase play signaling to prevent termination of the play bouts by mothers of younger partners.
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Lilienfeld, S. O., Gershon, J., Duke, M., Marino, L., & de Waal, F. B. (1999). A preliminary investigation of the construct of psychopathic personality (psychopathy) in chimpanzees (Pan troglodytes). J Comp Psychol, 113(4), 365–375.
Abstract: Although the construct of psychopathy has received considerable attention in humans, its relevance to other animals is largely unknown. We developed a measure of psychopathy for use in chimpanzees (Pan troglodytes), the Chimpanzee Psychopathy Measure (CPM), and asked 6 raters to complete this index on 34 chimpanzees. The CPM (a) demonstrated satisfactory interrater reliability and internal consistency; (b) exhibited marginally significant sex differences (males > females); (c) correlated positively with measures of extraversion, agreeableness, and observational ratings of agonism, sexual activity, daring behaviors, teasing, silent bluff displays, and temper tantrums, and negatively with observational ratings of generosity; and (d) demonstrated incremental validity above and beyond a measure of dominance. Although further validation of the CPM is needed, these findings suggest that the psychopathy construct may be relevant to chimpanzees.
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Verrill, S., & McDonnell, S. (2008). Equal Outcomes with and without Human-to-Horse Eye Contact When Catching Horses and Ponies in an Open Pasture. Journal of Equine Veterinary Science, 28(5), 309–312.
Abstract: Each of 104 horses and ponies was approached for catching at pasture by the same human handler in a standard manner, either maintaining human-to-animal eye contact (EC+; n = 51) or avoiding eye contact (EC-; n = 53). A subset of 74 of these subjects were reevaluated 3 weeks later under similar standard conditions except with the eye contact condition opposite to that used in the first round. Nonparametric statistical methods were used to evaluate between subjects (round 1, n = 104) and within subjects (rounds 1 and 2, n = 74) comparisons of successful or unsuccessful catching outcome with EC+ and EC-. Catching outcomes were similar with eye contact condition. Although this study represents a single handler at one study site, results suggest that human-to-horse eye contact may not be an important influence on catching pastured horses. Certainly, further work is needed to better understand the role of eye contact in horse handling.
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Gibbs, P. G., & Cohen, N. D. (2001). Early management of race-bred weanlings and yearlings on farms. J. Equine Vet. Sci., 21(6), 279–283.
Abstract: A total of 58 Thoroughbred and Quarter Horse farms
that managed 1,987 weanlings and yearlings responded to
a survey designed to better characterize early management
of racing prospects. Average age at weaning was 5.5 months
and over half of all farms kept almost three-fourths of all
weanlings to be placed in pre-race training. Variation in
feeding practices was evident and while well over half
of all farms provided balanced nutrient supply to young
horses, 20% to 40% likely fed unbalanced diets. An obvious
preference existed for semi-confinement in young horses
with plenty of free exercise. The majority of farms reported
that young prospects were fed and managed for a moderate
rate of growth. Forced exercise occurred to a much larger
extent with yearlings than weanlings and 40% of farms
described the footing as soft, but not deep. Response to the
prevalence of developmental orthopedic diseases appeared
somewhat guarded, and average injury rate was low on
farms that attributed much of injury to horses playing too
hard. Technological advancements such as photoperiod
manipulation in broodmares were widely used, while
valuable tools such as body condition scoring were utilized
to a lesser extent.
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Nissani, M. (2006). Do Asian elephants (Elephas maximus) apply causal reasoning to tool-use tasks? J Exp Psychol Anim Behav Process, 32(1), 91–96.
Abstract: Two experiments addressed contradictory claims about causal reasoning in elephants. In Experiment 1, 4 Asian elephants (Elephas maximus) were pretrained to remove a lid from the top of a bucket and retrieve a food reward. Subsequently, in the first 5 critical trials, when the lid was placed alongside the bucket and no longer obstructed access to the reward, each elephant continued to remove the lid before retrieving the reward. Experiment 2, which involved 11 additional elephants and variations of the original design, yielded similarly counterintuitive observations. Although the results are open to alternative interpretations, they appear more consistent with associative learning than with causal reasoning. Future applications of Fabrean methodologies (J. H. Fabre, 1915) to animal cognition are proposed.
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Vlamings, P. H. J. M., Uher, J., & Call, J. (2006). How the great apes (Pan troglodytes, Pongo pygmaeus, Pan paniscus, and Gorilla gorilla) perform on the reversed contingency task: the effects of food quantity and food visibility. J Exp Psychol Anim Behav Process, 32(1), 60–70.
Abstract: S. T. Boysen and G. G. Berntson (1995) found that chimpanzees performed poorly on a reversed contingency task in which they had to point to the smaller of 2 food quantities to acquire the larger quantity. The authors compared the performance of 4 great ape species (Pan troglodytes, Pongo pygmaeus, Pan paniscus, and Gorilla gorilla) on the reversed contingency task while manipulating food quantity (0-4 or 1-4) and food visibility (visible pairs or covered pairs). Results showed no systematic species differences but large individual differences. Some individuals of each species were able to solve the reversed contingency task. Both quantity and visibility of the food items had a significant effect on performance. Subjects performed better when the disparity between quantities was smaller and the quantities were not directly visible.
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Manns, J. R., Clark, R. E., & Squire, L. R. (2002). Standard delay eyeblink classical conditioning is independent of awareness. J Exp Psychol Anim Behav Process, 28(1), 32–37.
Abstract: P. F. Lovibond and D. R. Shanks (2002) suggested that all forms of classical conditioning depend on awareness of the stimulus contingencies. This article considers the available data for eyeblink classical conditioning, including data from 2 studies (R. E. Clark, J. R. Manns, & L. R. Squire, 2001; J. R. Manns, R. E. Clark, & L. R. Squire, 2001) that were completed too recently to have been considered in their review. In addition, in response to questions raised by P. F. Lovibond and D. R. Shanks, 2 new analyses of data are presented from studies published previously. The available data from humans and experimental animals provide strong evidence that delay eyeblink classical conditioning (but not trace eyeblink classical conditioning) can be acquired and retained independently of the forebrain and independently of awareness. This conclusion applies to standard conditioning paradigms; for example, to single-cue delay conditioning when a tone is used as the conditioned stimulus (CS) and to differential delay conditioning when the positive and negative conditioned stimuli (CS+ and CS-) are a tone and white noise.
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Nakamura, K. (2001). Perseverative errors in object discrimination learning by aged Japanese monkeys (Macaca fuscata). J Exp Psychol Anim Behav Process, 27(4), 345–353.
Abstract: To examine the nature of age-dependent cognitive decline, performance in terms of concurrent object discriminations was assessed in aged and nonaged Japanese monkeys (Macaca fuscata). Aged monkeys required more sessions and committed more errors than nonaged ones in the discriminations, even in simple object discriminations. Analyses of errors suggest that aged monkeys repeated the same errors and committed more errors when they chose a negative object at the 1st trial. A hypothesis analysis of behavior suggests that their incorrect choices were mainly due to object preference. Therefore, the impairment was probably caused by a failure to inhibit inappropriate responses. Together with previous neuropsychological findings, deficits of aged monkeys in the performance of object discriminations can be explained by dysfunction of the frontal cortex.
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Domjan, M. (1977). Selective suppression of drinking during a limited period following aversive drug treatment in rats. J Exp Psychol Anim Behav Process, 3(1), 66–76.
Abstract: Administration of lithium chloride disrupted the intake of flavored solutions but not water in rats. This intake suppression was directly related to the amount of lithium administered (Experiment 1), occurred with both palatable and unpalatable novel saccharin solutions (Experiment 2), but was only observed if subjects were tested starting less than 75 min. after lithium treatment (Experiment 3). Twenty-five daily exposures to saccharin did not attenuate the effect (Experiment 4). However, in saccharin-reared and vinegar-reared rats, lithium did not disrupt consumption of the solutions these subjects had access to throughout life, even though suppressions of intake were observed when these subjects were tested with novel flavors (Experiment 5). The selective disruption of drinking is interpreted as a novelty-dependent sensitization reaction to the discomfort of aversive drug administration.
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