|
|
Goodloe, R. B. (2000). Population characteristics of feral horses on Cumberland Island, Georgia and their management implications. J Wildl Manag, 64(1), 114–121.
|
|
|
|
Le Pendu, Y., Guilhem, C., Briedermann, L., Maublanc, M. - L., & Gerard, J. - F. (2000). Interactions and associations between age and sex classes in mouflon sheep (Ovis gmelini) during winter. Behav. Process., 52(2-3), 97–107.
|
|
|
|
Potì, P. (2000). Aspects of spatial cognition in capuchins (Cebus apella): frames of reference and scale of space. Anim. Cogn., 3(2), 69–77.
Abstract: Frames of reference (i.e. sets of loci defining spatial locations) determine animals' performances in object search tasks. Reference frames are used at different scales. Although much behavioural research has been conducted on search strategies in many animal species, relatively little has been done on nonhuman primates. The two experiments reported here focused on the relative strength and the level of functioning of different reference frames at the small-scale level in four capuchins (Cebus apella). Two identical boxes and a landmark were placed on a round platform that could be rotated. A reward was hidden in subject's view under one box, and then a sash-screen was lowered to hide the rotation of the platform; the sash-screen was then lifted and the subject allowed to search for the reward. In experiment 1 the rewarded box was always the closer to the landmark, in experiment 2 it could be either the box closer to or the box farther from the landmark. Capuchins were successful after invisible rotations in experiment 1, but they failed after invisible rotations in experiment 2. Two possible explanations are proposed: (1) capuchins relied heavily on the left-right body-axis as a frame, and they could only substitute it with a simple association between the rewarded position and the landmark; or (2) capuchins failed because they chose external cues in the room, therefore on a inappropriate scale. The latter explanation allows two further inferences: (a) the capuchins' choice was indirectly related to their body-axes; and (b) the capuchins revealed a cognitive asymmetry between small-scale and large-scale spaces, thus differing from humans.
|
|
|
|
Miklósi, A. '., Polgárdi, R., Topál, J., & Csányi, V. (2000). Intentional behaviour in dog-human communication: an experimental analysis of “showing” behaviour in the dog. Anim. Cogn., 3(3), 159–166.
Abstract: Despite earlier scepticism there is now evidence for simple forms of intentional and functionally referential communication in many animal species. Here we investigate whether dogs engage in functional referential communication with their owners. “Showing” is defined as a communicative action consisting of both a directional component related to an external target and an attention-getting component that directs the attention of the perceiver to the informer or sender. In our experimental situation dogs witness the hiding of a piece of food (or a favourite toy) which they cannot get access to. We asked whether dogs would engage in “showing” in the presence of their owner. To control for the motivational effects of both the owner and the food on the dogs' behaviour, control observations were also staged where only the food (or the toy) or the owner was present. Dogs' gazing frequency at both the food (toy) and the owner was greater when only one of these was present. In other words, dogs looked more frequently at their owner when the food (toy) was present, and they looked more at the location of the food (toy) when the owner was present. When both the food (toy) and the owner were present a new behaviour, “gaze alternation”, emerged which was defined as changing the direction of the gaze from the location of the food (toy) to looking at the owner (or vice versa) within 2 s. Vocalisations that occurred in this phase were always associated with gazing at the owner or the location of the food. This behaviour, which was specific to this situation, has also been described in chimpanzees, a gorilla and humans, and has often been interpreted as a form of functionally referential communication. Based on our observations we argue that dogs might be able to engage in functionally referential communication with their owner, and their behaviour could be described as a form of “showing”. The contribution of domestication and individual learning to the well-developed communicative skills in dogs is discussed and will be the subject of further studies.
|
|
|
|
Ray, E. D., Gardner, M. R., & Heyes, C. M. (2000). Seeing how it's done: matching conditions for observer rats (Rattus norvegicus) in the bidirectional control. Anim. Cogn., 3(3), 147–157.
Abstract: In an attempt to increase the reliability of the demonstrator-consistent responding effect produced in the bidirectional control procedure, experiments 1-4 sought conditions that would magnify the matching effect. The aim was to produce a robust demonstrator-consistent responding effect in order that future analytic experiments could investigate the psychological processes responsible for this effect. The joystick responses of observer rats trained using the standard bidirectional control procedure parameters were compared with those of observers subject to conditions identified in the social learning literature as favourable for imitation. Unlike mice, observer rats in experiments 1 a and 1 b tended to push a joystick in the same direction as their demonstrators when the demonstrators were either familiar or unfamiliar males and females. Comparable demonstrator-consistent responding occurred following observation of a standard and a salient joystick response (experiment 2). Experiment 3 showed that the discriminative accuracy of a demonstrator's responding was important for matching behaviour, and suggested that matching might be enhanced with more than the conventional single observation session. Experiment 4 confirmed that the bidirectional control effect is sensitive to the amount of observational experience; after six observation sessions, demonstrator-inconsistent responding occurs. The results of experiments 1-3 are, and those of experiment 4 are not, compatible with the hypothesis that demonstrator-consistent responding in the bidirectional control is caused by olfactory cues deposited by demonstrators on the joystick.
|
|
|
|
Mercado E., Killebrew D.A., Pack A.A., Macha I.V.B., & Herman L.M. (2000). Generalization of 'same-different' classification abilities in bottlenosed dolphins. Behav. Process., 50, 79–94.
|
|
|
|
Byrne R.W. (2000). - Animal Cognition in Nature, edited by Russell P. Balda, Irene M. Pepperberg and Alan C. Kamil. Trends. Cognit. Sci., 4, 73.
|
|
|
|
McKinley, J., & Sambrook, T. D. (2000). Use of human-given cues by domestic dogs (Canis familiaris) and horses (Equus caballus). Anim. Cogn., 3(1), 13–22.
Abstract: Sixteen domestic dogs (Canis familiaris) and four horses (Equus caballus) were tested for their ability to use human-given manual and facial cues in an object-choice task. Two of the four horses used touch as a cue and one horse successfully used pointing. The performance of the dogs was considerably better, with 12 subjects able to use pointing as a cue, 4 able to use head orientation and 2 able to use eye gaze alone. Group analysis showed that the dogs performed significantly better in all experimental conditions than during control trials. Dogs were able to use pointing cues even when the cuer's body was closer to the incorrect object. Working gundogs with specialised training used pointing more successfully than pet dogs and gundog breeds performed better than non-gundog breeds. The results of this experiment suggest that animals' use of human given communicative signals depends on cognitive ability, the evolutionary consequences of domestication and enculturation by humans within the individual's lifetime.
|
|
|
|
Miyashita, Y., Nakajima, S., & Imada, H. (2000). Differential outcome effect in the horse. J Exp Anal Behav, 74(2), 245–253.
Abstract: hree horses were trained with a discrimination task in which the color (blue or yellow) of a center panel signaled the correct (left or right) response (lever press). Reinforcing outcomes for the two correct color-position combinations (blue-left and yellow-right) were varied across phases. Discrimination performance was better when the combinations were differentially reinforced by two types of food (chopped carrot pieces and a solid food pellet) than when the combinations were randomly reinforced by these outcomes or when there was a common reinforcer for each of the correct combinations. However, the discrimination performance established by the differential outcome procedure was still 80% to 90% correct, and an analysis of two-trial sequences revealed that the stimulus color of the preceding trial interfered with discrimination performance on a given trial. Our demonstration of the differential outcome effect in the horse and its further analysis might contribute to more efficient control of equine behavior in the laboratory as well as in horse sports.
|
|
|
|
Bailey, A., Williams, N., Palmer, M., & Geering, R. (2000). The farmer as service provider: the demand for agricultural commodities and equine services. Agricultural Systems, 66(3), 191–204.
Abstract: In recent years there has been much interest in alternative sources of income for farmers. This is because economic theory suggests that demand for agricultural commodities is inelastic so that, as incomes in society as a whole increase, those of farmers do not necessarily keep pace — hence the current problems with falling real farm incomes. In contrast the demand for services is relatively elastic. Thus it is logical to divert agricultural resources into service provision. One such service is provided by equine enterprises. We have estimated the own price and income elasticities of demand for selected agricultural commodities and for ‘equine services’. Our results confirm that demand for equine services is more elastic than for agricultural commodities. Thus diversification into horse enterprises is likely to have long term benefits for farmers vis á vis traditional agricultural production.
|
|
