title: Handedness for grasping objects and declarative pointing: a longitudinal study.
abstract: It is still unclear whether infants become right-handed because of their left-hemisphere specialization for language (through gestural communication for instance), whether they speak predominantly with their left hemisphere because of this hemisphere's superiority in controlling sequential actions which first results in right-handedness, or whether the two lateralization processes develop independently. To tackle this question, we followed 26 human infants from 8 to 20 months to evaluate the temporal relationship between the emergence of hand preference for grasping objects and for declarative pointing (communicative gesture). Our results show that when grasping and pointing are compared in similar conditions, with objects presented in several spatial positions, the tendency to use the right hand is significantly larger for pointing than for grasping, and both hand preferences are loosely correlated. This suggests that, at least at the age studied here, hand preferences for grasping and for declarative pointing develop relatively independently.
authors.affiliation: Laboratoire Psychologie de la Perception, Université Paris Descartes, CNRS UMR 8158, 45 rue des Sts Pères, 75006 Paris, France.
authors.forename: Anne-Yvonne
authors.initials: AY
authors.lastname: Jacquet
authors.forename: Rana
authors.initials: R
authors.lastname: Esseily
authors.forename: Delphine
authors.initials: D
authors.lastname: Rider
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Fagard
mesh_terms: D002657:Child Development / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D005868:Gestures; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D007223:Infant; D008137:Longitudinal Studies; D008297:Male; D009043:Motor Activity / Q000502:physiology*