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Author (up) Timney, B.; Keil, K. doi  openurl
  Title Local and global stereopsis in the horse Type 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  
  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 0042-6989 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:10343877 Approved yes  
  Call Number Equine Behaviour @ team @ Serial 3580  
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