Using Object Knowledge in Visual Tracking and Reaching

Abstract

Nine‐month‐old infants were presented with an engaging and challenging task of visually tracking and reaching for a rolling ball that disappeared and reappeared from behind an occluder. On some trials, the infant observed the experimenter place a barrier on the ball's track; the barrier remained partially visible above the occluder throughout the remainder of the trial. When the task involved only predictive tracking, infants' anticipatory gaze shifts were faster when no barrier was present. When the task involved both tracking and reaching, there were more reaches when no barrier was present. If the infant reached, the timing and extension of the reach and the accompanying gaze shift did not differ with regard to the barrier. Because catching the ball was quite difficult for these infants, task demands interfered with the integration of visual information and visuospatial reasoning about the barrier with the reaching action.

Décalage in infants' knowledge about occlusion and containment events: Converging evidence from action tasks

“…Berthier et al, 2001;Keen et al, 2003). In the present research, task demands were fairly minimal, and the infants revealed the same physical knowledge as in prior VOE tasks.…”

“…According to a third, processing-load account (e.g. Berthier et al, 2001;Boudreau & Bushnell, 2000;Keen, Carrico, Sylvia, & Berthier, 2003), infants fail to reveal their physical knowledge in an action task when the total processing demands of the task overwhelm their limited resources; processing demands depend on both (1) the complexity of the actions involved and (2) the complexity of the physical reasoning involved.…”

“…Berthier et al, 2001;Keen et al, 2003). In some experiments, for example, 8.5-month-olds watched a ball roll down a ramp and along a track that was partly hidden by a short screen.…”

“…Second, such evidence would be relevant to discussions of the conditions under which infants' physical knowledge successfully guides their actions (e.g. Berthier et al, 2001;Diamond & Lee, 2000;Spelke & Hespos, 2001); we return to this issue below.…”

Action and perception in infancy

“…Netelenbos, 2000). Although direct experimentation to test these alternative hypotheses has only started very recently (e.g., Berthier et al, 2001;Von Hofsten et al, 1998), a selective review of the literature suggests that in infancy vision for action and vision for perception are separate and develop independently. For instance, the study reported by Jouen, Lepecq, Gapenne, and Bertenthal (this issue) convincingly demonstrates that 3-day-old infants adjust their backward head movements to optic flow velocity.…”