Evidence of Motor Planning in Infant Reaching Behavior

Abstract

When adults reach for an object, kinematic measures of their approach movement are affected by what they intend to do after grasping it. We examined whether such future intended actions would be reflected in the approach-to-grasp phase of infant reaching. Twenty-one 10-month-old infants were encouraged to either throw a ball into a tub or fit it down a tube. Kinematic measures of the approach phase of the reach toward the ball were obtained using a motion analysis system. Infants, like adults, reached for the ball faster if they were going to subsequently throw it as opposed to using it in the precision action. The perceptual aspects of the ball were the same and cannot account for these kinematic differences. Infants appear to be planning both segments of their actions in advance. Our findings provide evidence for a level of sophistication in infant motor planning not reported before.

Fitting objects into holes: On the development of spatial cognition skills.

“…As already mentioned, they tend to make decisions without complete information. We can draw a parallel to the ramp studies conducted by Keen and colleagues (Claxton, Keen et al 2003;Keen 2005;Kloos and Keen 2005;Kloos, Haddad et al 2006;Shutts, Keen et al 2006). Two-year-old children were unable to identify a ball's hiding place by means of indirect cues.…”

“…The handling of an object depends on the intention of the action (Manoel and Connolly 1998;Claxton, Keen et al 2003). For example, tenmonth-olds reached faster for a ball that they were going to throw into a bucket as opposed to fit into a tube (Claxton, Keen et al 2003).…”

“…For example, tenmonth-olds reached faster for a ball that they were going to throw into a bucket as opposed to fit into a tube (Claxton, Keen et al 2003). The first action (although grasping the object) is carried out differently depending on what the subsequent action is.…”

“…When five-to nine-year-old children were to get groceries from a list in a play store, older children more often took time to pause, scan and gather enough information to find the smartest solution while the younger children acted more rashly (Gauvain and Rogoff 1989;Szepkouski, Gauvain et al 1994). To make a choice without complete information can be related to the studies by Keen and colleagues (Claxton, Keen et al 2003;Keen 2005;Kloos and Keen 2005;Kloos, Haddad et al 2006;Shutts, Keen et al 2006). In these studies, a ball rolling down a ramp could be blocked at different points by a barrier.…”

Goal directedness and decision making in infants.

“…The first example is when infants late in their second year reach around a transparent barrier using a two-step motion in order to grasp an object -a task which younger infants fail because they attempt to reach directly though the barrier for the visible object (Diamond, 1990). The second example is that 10-month-olds reach more slowly to grasp a ball when they will subsequently insert it into a tube than when they will subsequently throw it into a tub -inserting here requires more precision than throwing and is therefore facilitated by a slower preceding movement (Claxton, Keen, & McCarty, 2003).…”