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Author (up) De Boyer Des Roches, A.; Richard-Yris, M.-A.; Henry, S.; Ezzaouia, M.; Hausberger, M.
Title Laterality and emotions: visual laterality in the domestic horse (Equus caballus) differs with objects' emotional value Type Journal Article
Year 2008 Publication Physiology & Behavior Abbreviated Journal Physiol. Behav.
Volume 94 Issue 3 Pages 487-490
Keywords Animals; Animals, Newborn; Behavior, Animal/physiology; Dominance, Ocular/*physiology; *Emotions; Exploratory Behavior/physiology; Female; Horses/*physiology; Olfactory Pathways/physiology; Pattern Recognition, Visual/*physiology; Photic Stimulation; Pregnancy; Statistics, Nonparametric; Visual Fields/physiology
Abstract Lateralization of emotions has received great attention in the last decades, both in humans and animals, but little interest has been given to side bias in perceptual processing. Here, we investigated the influence of the emotional valence of stimuli on visual and olfactory explorations by horses, a large mammalian species with two large monocular visual fields and almost complete decussation of optic fibres. We confronted 38 Arab mares to three objects with either a positive, negative or neutral emotional valence (novel object). The results revealed a gradient of exploration of the 3 objects according to their emotional value and a clear asymmetry in visual exploration. When exploring the novel object, mares used preferentially their right eyes, while they showed a slight tendency to use their left eyes for the negative object. No asymmetry was evidenced for the object with the positive valence. A trend for an asymmetry in olfactory investigation was also observed. Our data confirm the role of the left hemisphere in assessing novelty in horses like in many vertebrate species and the possible role of the right hemisphere in processing negative emotional responses. Our findings also suggest the importance of both hemispheres in the processing positive emotions. This study is, to our knowledge, the first to demonstrate clearly that the emotional valence of a stimulus induces a specific visual lateralization pattern.
Address UMR CNRS 6552 Ethologie-Evolution-Ecologie, Universite de Rennes 1, Avenue du General Leclerc, Campus de Beaulieu, F-35042 Rennes Cedex, France. a.de-boyer@wanadoo.fr
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9384 ISBN Medium
Area Expedition Conference
Notes PMID:18455205 Approved no
Call Number Equine Behaviour @ team @ Serial 4762
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Author (up) Rogers, L.J.
Title Evolution of hemispheric specialization: advantages and disadvantages Type Journal Article
Year 2000 Publication Brain and Language Abbreviated Journal Brain Lang
Volume 73 Issue 2 Pages 236-253
Keywords Aggression/psychology; Animals; Behavior, Animal/physiology; Brain/*physiology; Chickens/physiology; *Evolution; Feeding Behavior/physiology; Functional Laterality/*physiology; Visual Fields/physiology; Visual Perception/physiology
Abstract Lateralization of the brain appeared early in evolution and many of its features appear to have been retained, possibly even in humans. We now have a considerable amount of information on the different forms of lateralization in a number of species, and the commonalities of these are discussed, but there has been relatively little investigation of the advantages of being lateralized. This article reports new findings on the differences between lateralized and nonlateralized chicks. The lateralized chicks were exposed to light for 24 h on day 19 of incubation, a treatment known to lead to lateralization of a number of visually guided responses, and the nonlateralized chicks were incubated in the dark. When they were feeding, the lateralized chicks were found to detect a stimulus resembling a raptor with shorter latency than nonlateralized chicks. This difference was not a nonspecific effect caused by the light-exposed chicks being more distressed by the stimulus. Instead, it appears to be a genuine advantage conferred by having a lateralized brain. It is suggested that having a lateralized brain allows dual attention to the tasks of feeding (right eye and left hemisphere) and vigilance for predators (left eye and right hemisphere). Nonlateralized chicks appear to perform these dual tasks less efficiently than lateralized ones. Reference is made to other species in discussing these results.
Address Division of Zoology, University of New England, Armidale, New South Wales, Australia. lrogers@metz.une.edu.au
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0093-934X ISBN Medium
Area Expedition Conference
Notes PMID:10856176 Approved no
Call Number Equine Behaviour @ team @ Serial 4621
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