Figure 1.
a) The eight initial positions of the handled-rod and slot presented to children in the experiment. b) The experimental setup – depicted here is a handled object with the handle on the right with a horizontal slot. Reflective markers (highlighted in blue) were placed on the 3rd metacarpal (knuckle), ulnar styloid (wrist), radial styloid (wrist), and ends of slot, rod, and handle. c) Depicted here is when the handled object approaches the slot. (The authors received signed consent for the child's likeness to be published in this article)