Target animacy influences gorilla handedness
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We investigated the unimanual actions of a biological family group of twelve western lowland gorillas (Gorilla gorilla gorilla) using a methodological approach designed to assess behavior within social context from a bottom-up perspective. Measures of both the lateralization of unimanual actions (left, right) and the target of the action (animate, inanimate) were assessed during dual, synchronized video observations of naturalistic behavior. This paper demonstrates a corelationship between handedness and the animate quality of the target object. Analyses demonstrated a significant interaction between lateralized unimanual actions and target animacy and a right-hand bias for actions directed toward inanimate targets. We suggest that lateralized motor preference reflects the different processing capabilities of the left and right hemispheres, as influenced by the emotive (animate) and/or functional (inanimate) characteristics of the target, respectively.
KeywordsHandedness Animacy Hemispheric specialization Gorilla
We thank Phil Ridges and the Aspinall Foundation for research access to gorillas, Kim Bard for discussions on methodological design, JointSoftware for software development and Roberta Herrick for assistance with data collection. This study was funded in part by the Daphne Jackson Trust and the Gatsby Charitable Foundation.
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