| Records |
| Author |
Macuda, T.; Timney, B. |
| Title |
Luminance and chromatic discrimination in the horse (Equus caballus) |
Type |
Journal Article |
| Year |
1999 |
Publication |
Behavioural Processes |
Abbreviated Journal |
Behav. Process. |
| Volume |
44 |
Issue |
3 |
Pages |
301-307 |
| Keywords |
Colour vision; Chromatic discrimination; Luminance discrimination; Horse |
| Abstract |
Equine colour vision was measured under conditions that minimised the possibility of animals using brightness cues to make chromatic discriminations. In a two-stage study, we first obtained luminance discrimination functions for achromatic targets then tested for chromatic discrimination over a range of target luminances. Horses were trained on a two-choice discrimination task. The positive stimulus was varied in luminance and/or colour using neutral density and broad band colour filters. The negative stimulus appeared as a uniform grey. In the brightness discrimination task, the horses performed well at large luminance differences but their percentage of correct responses declined to near chance levels at differences of less than 0.2 log units. In addition, a decrement in performance was noted at luminance differences of less than 0.2 log units for green and yellow chromatic discrimination functions, suggesting that horses cannot easily discriminate yellow and green from grey. However, the chromatic discrimination functions for red and blue showed that animals performed very well across the full range of target luminances. These results suggest that horses are at least dichromats. |
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844 |
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| Author |
Tomkins, L.M.; Williams, K.A.; Thomson, P.C.; McGreevy, P.D. |
| Title |
Sensory Jump Test as a measure of sensory (visual) lateralization in dogs (Canis familiaris) |
Type |
Journal Article |
| Year |
2010 |
Publication |
Journal of Veterinary Behavior |
Abbreviated Journal |
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| Volume |
5 |
Issue |
5 |
Pages |
256-267 |
| Keywords |
sensory lateralization; monocular vision; binocular vision; jump kinematics; dog |
| Abstract |
Sensory lateralization in dogs (n = 74) was investigated in this study using our innovation, the Sensory Jump Test. This required the modification of head halters to create three different ocular treatments (binocular, right, and left monocular vision) for eye preference assessment in a jumping task. Ten jumps were recorded as a jump set for each treatment. Measurements recorded included (i) launch and landing paws, (ii) type of jump, (iii) approach distance, (iv) clearance height of the forepaw, hindpaw, and the lowest part of the body to clear the jump, and (v) whether the jump was successful. Factors significantly associated with these jump outcomes included ocular treatment, jump set number, and replication number. Most notably, in the first jump set, findings indicated a left hemispheric dominance for the initial navigation of the Sensory Jump Test, as left monocular vision (LMV) compromised of jumping more than right monocular (RMV) and binocular vision, with a significantly reduced approach distance and forepaw clearance observed in dogs with LMV. However, by the third jump set, dogs undergoing LMV launched from a greater approach distance and with a higher clearance height, corresponding to an increase in success rate of the jump, in comparison with RMV and binocular vision dogs. A marginally non-significant RMV bias was observed for eye preference based on the laterality indices for approach distance (P = 0.060) and lowest body part clearance height (P = 0.067). A comparison between eye preference and launching or landing paws showed no association between these measures of sensory and motor laterality. To our knowledge, this is the first study to report on sensory lateralization in the dog, and furthermore, to compare both motor and sensory laterality in dogs. |
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1558-7878 |
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Equine Behaviour @ team @ S1558-7878(10)00019-5 |
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5379 |
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| Author |
Farmer, K.; Krueger, K.; Byrne, R. |
| Title |
Visual laterality in the domestic horse (Equus caballus) interacting with humans |
Type |
Journal Article |
| Year |
2010 |
Publication |
Animal Cognition |
Abbreviated Journal |
Anim. Cogn. |
| Volume |
13 |
Issue |
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Pages |
229-238 |
| Keywords |
Horse – Laterality – Eye preference – Emotion – Vision |
| Abstract |
Most horses have a side on which they are easier to handle and a direction they favour when working on a circle, and recent studies have suggested a correlation between emotion and visual laterality when horses observe inanimate objects. As such lateralisation could provide important clues regarding the horse’s cognitive processes, we investigated whether horses also show laterality in association with people. We gave horses the choice of entering a chute to left or right, with and without the passive, non-interactive presence of a person unknown to them. The left eye was preferred for scanning under both conditions, but significantly more so when a person was present. Traditionally, riders handle horses only from the left, so we repeated the experiment with horses specifically trained on both sides. Again, there was a consistent preference for left eye scanning in the presence of a person, whether known to the horses or not. We also examined horses interacting with a person, using both traditionally and bilaterally trained horses. Both groups showed left eye preference for viewing the person, regardless of training and test procedure. For those horses tested under both passive and interactive conditions, the left eye was preferred significantly more during interaction. We suggest that most horses prefer to use their left eye for assessment and evaluation, and that there is an emotional aspect to the choice which may be positive or negative, depending on the circumstances. We believe these results have important practical implications and that emotional laterality should be taken into account in training methods. |
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Equine Behaviour @ team @ |
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4953 |
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| Author |
Bartoš, L.; Bartošová, J.; Starostová, L. |
| Title |
Position of the head is not associated with changes in horse vision |
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Journal Article |
| Year |
2008 |
Publication |
Equine Veterinary Journal |
Abbreviated Journal |
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| Volume |
40 |
Issue |
6 |
Pages |
599-601 |
| Keywords |
horse; horse vision; head position; pupil rotation |
| Abstract |
It has become accepted that the horse cannot see directly in front when the nose is lowered and must therefore rely on the rider. We tested the hypothesis that this conclusion would be correct only if the horse did not adjust the eyeball horizontal axis to changes of the head position. The results of the present study suggest that it is unlikely that horses have limited vision in relation to their head position when driven by the rider, and that the horse maintains the optimal horizontal eyeball position regardless of head position relative to the ground. |
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Blackwell Publishing Ltd |
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2042-3306 |
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no |
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Equine Behaviour @ team @ |
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5679 |
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| Author |
Anderson, C.; Franks, N.R. |
| Title |
Teams in animal societies |
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Journal Article |
| Year |
2001 |
Publication |
Behavioral Ecology |
Abbreviated Journal |
Behav. Ecol. |
| Volume |
12 |
Issue |
5 |
Pages |
534-540 |
| Keywords |
animal societies, cooperation, division of labor, groups, invertebrates, task types, teams, vertebrates |
| Abstract |
We review the existence of teams in animal societies. Teams have previously been dismissed in all but a tiny minority of insect societies. “Team” is a term not generally used in studies of vertebrates. We propose a new rigorous definition of a team that may be applied to both vertebrate and invertebrate societies. We reconsider what it means to work as a team or group and suggest that there are many more teams in insect societies than previously thought. A team task requires different subtasks to be performed concurrently for successful completion. There is a division of labor within a team. Contrary to previous reviews of teams in social insects, we do not constrain teams to consist of members of different castes and argue that team members may be interchangeable. Consequently, we suggest that a team is simply the set of individuals that performs a team task. We contrast teams with groups and suggest that a group task requires the simultaneous performance and cooperation of two or more individuals for successful completion. In a group, there is no division of labor--each individual performs the same task. We also contrast vertebrate and invertebrate teams and find that vertebrate teams tend to be associated with hunting and are based on individual recognition. Invertebrate teams occur in societies characterized by a great deal of redundancy, and we predict that teams in insect societies are more likely to be found in large polymorphic (“complex”) societies than in small monomorphic (“simple”) societies. |
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10.1093/beheco/12.5.534 |
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2070 |
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| Author |
Hare, B.; Brown, M.; Williamson, C.; Tomasello, M. |
| Title |
The domestication of social cognition in dogs |
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Journal Article |
| Year |
2002 |
Publication |
Science (New York, N.Y.) |
Abbreviated Journal |
Science |
| Volume |
298 |
Issue |
5598 |
Pages |
1634-1636 |
| Keywords |
Animals; *Animals, Domestic; *Behavior, Animal; *Cognition; *Cues; *Dogs; Food; Humans; Memory; Pan troglodytes; *Social Behavior; Species Specificity; Vision; Wolves |
| Abstract |
Dogs are more skillful than great apes at a number of tasks in which they must read human communicative signals indicating the location of hidden food. In this study, we found that wolves who were raised by humans do not show these same skills, whereas domestic dog puppies only a few weeks old, even those that have had little human contact, do show these skills. These findings suggest that during the process of domestication, dogs have been selected for a set of social-cognitive abilities that enable them to communicate with humans in unique ways. |
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Department of Anthropology, Harvard University, Cambridge, MA 02138, USA. bhare@fas.harvard.edu |
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English |
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1095-9203 |
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PMID:12446914 |
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no |
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refbase @ user @ |
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595 |
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| Author |
Harman, A.M.; Moore, S.; Hoskins, R.; Keller, P. |
| Title |
Horse vision and an explanation for the visual behaviour originally explained by the 'ramp retina' |
Type |
Journal Article |
| Year |
1999 |
Publication |
Equine veterinary journal |
Abbreviated Journal |
Equine Vet J |
| Volume |
31 |
Issue |
5 |
Pages |
384-390 |
| Keywords |
Animals; Behavior, Animal; Cell Count; Eye/*anatomy & histology; Ganglia, Sensory/cytology; Horses/*physiology; Refractive Errors/veterinary; Retina/cytology/*physiology; Vision/*physiology; Visual Acuity; Visual Fields |
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Here we provide confirmation that the 'ramp retina' of the horse, once thought to result in head rotating visual behaviour, does not exist. We found a 9% variation in axial length of the eye between the streak region and the dorsal periphery. However, the difference was in the opposite direction to that proposed for the 'ramp retina'. Furthermore, acuity in the narrow, intense visual streak in the inferior retina is 16.5 cycles per degree compared with 2.7 cycles per degree in the periphery. Therefore, it is improbable that the horse rotates its head to focus onto the peripheral retina. Rather, the horse rotates the nose up high to observe distant objects because binocular overlap is oriented down the nose, with a blind area directly in front of the forehead. |
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Department of Psychology, University of Western Australia, Nedlands, Australia |
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English |
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0425-1644 |
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PMID:10505953 |
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no |
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refbase @ user @ |
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836 |
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Garamszegi, L.Z.; Møller, A.P.; Erritzøe, J. |
| Title |
Coevolving avian eye size and brain size in relation to prey capture and nocturnality |
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Journal Article |
| Year |
2002 |
Publication |
Proceedings of the Royal Society of London. Series B: Biological Sciences |
Abbreviated Journal |
Proc Roy Soc Lond B Biol Sci |
| Volume |
269 |
Issue |
1494 |
Pages |
961-967 |
| Keywords |
adaptation; behaviour; brain size; coevolution; eye size; vision |
| Abstract |
Behavioural adaptation to ecological conditions can lead to brain size evolution. Structures involved in behavioural visual information processing are expected to coevolve with enlargement of the brain. Because birds are mainly vision–oriented animals, we tested the predictions that adaptation to different foraging constraints can result in eye size evolution, and that species with large eyes have evolved large brains to cope with the increased amount of visual input. Using a comparative approach, we investigated the relationship between eye size and brain size, and the effect of prey capture technique and nocturnality on these traits. After controlling for allometric effects, there was a significant, positive correlation between relative brain size and relative eye size. Variation in relative eye and brain size were significantly and positively related to prey capture technique and nocturnality when a potentially confounding variable, aquatic feeding, was controlled statistically in multiple regression of independent linear contrasts. Applying a less robust, brunching approach, these patterns also emerged, with the exception that relative brain size did not vary with prey capture technique. Our findings suggest that relative eye size and brain size have coevolved in birds in response to nocturnal activity and, at least partly, to capture of mobile prey. |
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10.1098/rspb.2002.1967 |
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Equine Behaviour @ team @ |
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5452 |
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| Author |
Timney, B.; Keil, K. |
| Title |
Local and global stereopsis in the horse |
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Journal Article |
| Year |
1999 |
Publication |
Vision Research |
Abbreviated Journal |
Vision Res |
| Volume |
39 |
Issue |
10 |
Pages |
1861-1867 |
| Keywords |
Animals; Depth Perception/*physiology; Female; Horses/*physiology; Pattern Recognition, Visual/physiology; Psychophysics; Sensory Thresholds/physiology; Vision, Binocular/physiology; Vision, Monocular/physiology |
| Abstract |
Although horses have laterally-placed eyes, there is substantial binocular overlap, allowing for the possibility that these animals have stereopsis. In the first experiment of the present study we measured local stereopsis by obtaining monocular and binocular depth thresholds for renal depth stimuli. On all measures, the horses' binocular performance was superior to their monocular. When depth thresholds were obtained, binocular thresholds were several times superior to those obtained monocularly, suggesting that the animals could use stereoscopic information when it was available. The binocular thresholds averaged about 15 min arc. In the second experiment we obtained evidence for the presence of global stereopsis by testing the animals' ability to discriminate between random-dot stereograms with and without consistent disparity information. When presented with such stimuli they showed a strong preference for the cyclopean equivalent of the positive stimulus with the real depth. These results provide the first behavioral demonstration of a full range of stereoscopic skills in a lateral-eyed mammal. |
| Address |
Department of Psychology, Faculty of Social Science, University of Western Ontario, London, Canada. timney@julian.uwo.ca |
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0042-6989 |
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PMID:10343877 |
Approved |
yes |
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Equine Behaviour @ team @ |
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3580 |
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| Author |
Hanggi, E.B.; Ingersoll, J.F. |
| Title |
Stimulus discrimination by horses under scotopic conditions |
Type |
Journal Article |
| Year |
2009 |
Publication |
Behavioural Processes |
Abbreviated Journal |
Behav. Process. |
| Volume |
82 |
Issue |
1 |
Pages |
45-50 |
| Keywords |
Discrimination learning; Equine; Horse; Night vision; Scotopic vision |
| Abstract |
Scotopic vision in horses (Equus caballus) was investigated using behavioral measurements for the first time. Four horses were tested for the ability to make simple visual discriminations of geometric figures (circles and triangles) under various brightness levels within an enclosed building. Measurements of brightness ranging from 10.37 to 24.12 magnitudes per square arcsecond (mag/arcsec2; in candelas per square meter--7.70 to 2.43E-05 cd/m2) were taken using a Sky Quality Meter. These values approximated outdoor conditions ranging from twilight in open country to a dark moonless night in dense forest. The horses were able to solve the discrimination problems in all brightness settings up to 23.77 mag/arcsec2 (3.35E-05 cd/m2). Moreover, they easily navigated their way around obstacles located within the testing area in extremely dim light (>23.50 mag/arcsec2; 4.30E-05 cd/m2), which were in conditions too dark for the human experimenters to see. These findings support physiological data that reveal a rod-dominated visual system as well as observations of equine activity at night. |
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0376-6357 |
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Equine Behaviour @ team @ |
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5051 |
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