title: Evidence for right-hand feeding biases in a left-handed population.
abstract: We have recently shown that actions with similar kinematic requirements, but different end-state goals may be supported by distinct neural networks. Specifically, we demonstrated that when right-handed individuals reach-to-grasp food items with intent to eat, they produce smaller maximum grip apertures (MGAs) than when they grasp the same item with intent to place it in a location near the mouth. This effect was restricted to right-handed movements; left-handed movements showed no difference between tasks. The current study investigates whether (and to which side) the effect may be lateralized in left-handed individuals. Twenty-one self-identified left-handed participants grasped food items of three different sizes while grasp kinematics were captured via an Optotrak Certus motion capture array. A main effect of task was identified wherein the grasp-to-eat action generated significantly smaller MGAs than did the grasp-to-place action. Further analysis revealed that similar to the findings in right-handed individuals, this effect was significant only during right-handed movements. Upon further inspection however, we found individual differences in the magnitude and direction of the observed lateralization. These results underscore the evolutionary significance of the grasp-to-eat movement in producing population-level right-handedness in humans as well as highlighting the heterogeneity of the left-handed population.
authors.affiliation: a The Brain in Action Laboratory, Department of Kinesiology and Physical Education , University of Lethbridge , Lethbridge , AB , Canada.
authors.forename: Jason W
authors.initials: JW
authors.lastname: Flindall
authors.forename: Kayla D
authors.initials: KD
authors.lastname: Stone
authors.forename: Claudia L R
authors.initials: CL
authors.lastname: Gonzalez
mesh_terms: D000704:Analysis of Variance; D015982:Bias; D001696:Biomechanical Phenomena; D005247:Feeding Behavior / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006225:Hand / Q000502:physiology*; D018737:Hand Strength; D006801:Humans; D008297:Male; D009010:Monte Carlo Method; D011597:Psychomotor Performance / Q000502:physiology*; D055815:Young Adult
keywords: Asymmetries; Grasp; Kinematics; Left-hand; Prehension