Abstract
This study aims at clarifying developmental changes of prehension during early childhood. Two hundred and twenty seven infants ranged from 30 to 69 months of age were asked to fill a circle with a felt-tip pen, and their processis were simultaneously monitored through four video cameras located at various position from the subjects. Reproducing the video tape, their prehensions of the pen were evaluated and were classified into seven different types. As the age increased, the infant tended to show “tripod grip” Upper limb-desk contacts were also classified into four different types. The more the age increased the more the distal upper limb tended to touch the desk. These results suggested that an acquisition of the tripod grip and a stable suspension made it possible to manipulate a pen effectively during early childhood.
