Visual exploration of reaching space during left and right arm movements in 6-month-old infants
Résumé
Infant’s manual laterality and eye-hand coordination emerge dur-ing the second part of the first year of life with the developmentof reaching. Nevertheless, little is known about the potential asym-metric characteristics of this coordination. The aim of this studywas to describe visuo-spatial exploration in 6-month-old infantsduring reaching, according to the hand used. More specifically, weexamined if the use of the left or the right hand was linked to a specific type of visual exploration. Gaze direction during goal-directed reaching towards an object placed on the table wasmeasured with a remote ASL 504 eye tracker (Bedford MA). Twelvebabies aged 6 months were observed during six reaching sessions,alterning three sessions with an object on the left side of the subjectand three with an object on the right side. Gaze direction and somehand variables (hand activity, hand opening and hand position fromthe body) were coded with The Observer software. Results showedthat babies visually explore their reaching space differently accord-ing to the hand used: they look more at the object when they usetheir right hand and more around the object when they use their lefthand; they also look more often at their left hand than at their rightone. These results suggest that an asymmetric visuo-manual coor-dination exists as early as 6 months: vision seems to support (1) lefthand during reaching for evaluate distances from object to baby bymeans of visual feedbacks and (2) right hand for identify what sortof object is. Results are discussed in light of manual specializationand specific hemispheric skills at this age.