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Appears in Collections:Psychology Journal Articles
Peer Review Status: Refereed
Title: Eye preferences in capuchin monkeys (Sapajus apella)
Author(s): Wilson, Duncan A
Tomonaga, Masaki
Vick, Sarah-Jane
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Keywords: Eye preferences
Behavioural laterality
Hemispheric specialisations
Capuchin monkeys
Issue Date: Jul-2016
Date Deposited: 30-Jun-2016
Citation: Wilson DA, Tomonaga M & Vick S (2016) Eye preferences in capuchin monkeys (Sapajus apella). Primates, 57 (3), pp. 433-440.;
Abstract: This study explored whether capuchin monkey eye preferences differ systematically in response to stimuli of positive and negative valence. The ‘valence hypothesis’ proposes that the right hemisphere is more dominant for negative emotional processing and the left hemisphere is more dominant for positive emotional processing. Visual information from each eye is thought to be transferred faster to and primarily processed by the contralateral cerebral hemisphere. Therefore, it was predicted capuchin monkeys would show greater left eye use for looking at negative stimuli and greater right eye use for looking at positive stimuli. Eleven captive capuchin monkeys were presented with four images of different emotional valence (an egg and capuchin monkey raised eyebrow face were categorised as positive, and a harpy eagle face and capuchin monkey threat face were categorised as negative) and social relevance (consisting of capuchin monkey faces or not), and eye preferences for viewing the stimuli through a monocular viewing hole were recorded. While strong preferences for using either the left or right eye were found for most individuals, there was no consensus at the population level. Furthermore, the direction of looking, number of looks and duration of looks did not differ significantly with the emotional valence of the stimuli. These results are inconsistent with the main hypotheses about the relationship between eye preferences and processing of emotional stimuli. However, the monkeys did show significantly more arousal behaviours (vocalisation, door-touching, self-scratching and hand-rubbing) when viewing the negatively valenced stimuli than the positively valenced stimuli, indicating that the stimuli were emotionally salient. These findings do not provide evidence for a relationship between eye preferences and functional hemispheric specialisations, as often proposed in humans. Additional comparative studies are required to better understand the phylogeny of lateral biases, particularly in relation to emotional valence.
DOI Link: 10.1007/s10329-016-0537-z
Rights: This item has been embargoed for a period. During the embargo please use the Request a Copy feature at the foot of the Repository record to request a copy directly from the author. You can only request a copy if you wish to use this work for your own research or private study. Publisher policy allows this work to be made available in this repository; Published in Primates, July 2016, Volume 57, Issue 3, pp 433–440 by Springer. The final publication is available at Springer via

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