Hand preference for precision grasping predicts language lateralization.
We investigated whether or not there is a relationship between hand preference for grasping and hemispheric dominance for language--and how each of these is related to other traditional measures of handedness. To do this we asked right- and left-handed participants to put together two different sets of 3D puzzles made out of big or very small LEGO pieces. Participants were also given two self-reported handedness questionnaires, as well as tests of grip force and finger tapping speed. A language lateralization (dichotic listening) test was also administered. We found a positive correlation between hand use for precision grasping and language lateralization (i.e. the more participants used their right hand for grasping the small LEGO pieces, the more language was lateralized to the left hemisphere). In addition, we identified two populations of left-handers according to their grasping performance: 'left-right-handers', who behaved exactly like right-handers; and 'left-left-handers' whose performance was the mirror image of that of right-handers. Finally, we found an increase in right-hand use when right-handers and 'left-right-handers' had to pick up the small LEGO pieces. We discuss our results in relation to recent notions of left-hemisphere specialization for visually guided actions and its relationship with the evolution of language.
Gonzalez
Claudia L R
CL
CIHR Group on Action and Perception, Department of Psychology, University of Western Ontario, London N6A5C2, Canada. claudia.gonzalez@uleth.ca
Goodale
Melvyn A
MA
D000328:Adult; D004007:Dichotic Listening Tests / Q000379:methods; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006225:Hand; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D007802:Language; D008297:Male; D008960:Models, Psychological; D011597:Psychomotor Performance / Q000502:physiology*; D012044:Regression Analysis; D011795:Surveys and Questionnaires; D055815:Young Adult