Multiple expressions of hemispheric asymmetry in captive chimpanzees

Laterality;Left- and right-handedness;Chimpanzees--Behavior;Cerebral dominance

Braccini, Stephanie ; Fitch, Tecumseh ; Fitch, Tecumseh

University:University of St Andrews

Department:Psychology & Neuroscience (School of)

关键词: Laterality;    Left- and right-handedness;    Chimpanzees--Behavior;    Cerebral dominance;   

Others  :  https://research-repository.st-andrews.ac.uk/bitstream/handle/10023/3227/StephanieBracciniPhDThesis.pdf?sequence=3&isAllowed=y

来源: DR-NTU

【 摘 要 】

The degree to which non-human primate behaviour is lateralized, at individual orpopulation levels, remains controversial and over the last century, the issue of brainlateralization in primates has been extensively researched and debated, yet no previous study has reported eye preference or head turning in great apes. This thesis examines three different expressions of hemispheric asymmetry in lateralized behaviours: hand preference for bipedal tool use, eye preference, and auditory laterality.It is reported that bipedalism induced the subjects to become more lateralized, but not in any particular direction. Instead, it appeared that subtle pre-existing lateral biases, to the right or left, were emphasized with increasing postural demands.Eye preference was assessed when animals looked through a hole, using one eye, at anempty box, a mirror, a picture of a dog, a rubber snake, food biscuits, bananas, a rubber duck and a video camera. Main effects of stimulus type were reported for direction of eye preference, number of looks, and looking duration, but not for strength of eyepreference. A left-eye bias was found for viewing the rubber snake and a right eye biaswas found for viewing the bananas. In addition, a significant shift in eye preference took place from the initial look to subsequent looks when viewing the snake. The results reported are not consistent with the literature for other primate studies.Lastly, auditory laterality was assessed using the Hauser and Andersson (1994) headturning paradigm. Chimpanzee and American crow calls were broadcast to subjectsfrom 180° behind them and directional head turning was recorded. No difference inturning direction or latency was found. This lack of result was attributed to themethodology and underlying assumption that head turning is directly related tohemispheric asymmetries and not influenced by any other processes.