< Page:First steps in mental growth (1906).djvu
This page has been proofread, but needs to be validated.

DEVELOPMENT OF HAND AND ARM MOVEMENTS

21

REFLEX HAND-MOVEMENTS

Reflex movements may be defined as those movements in which the excitation of an end organ is transmitted to a nerve center, and there directly and without conscious antecedents sets free an impulse which, through an outgoing nerve fibre, arouses activity in a muscle or other organ. Reflex movements are distinguished from spontaneous movements by the fact that they presuppose the existence of an external stimulus; and they are distinguished from instinctive movements by their greater simplicity—only a small number of muscles or other organs being involved in their production—and by the immediacy of the end they serve; and also by the absence of consciousness—particularly of characteristic moods or feeling-tones which arise in connection with instinctive actions.

The first note relating to reflex hand-movements which my record contains is with reference to clasping with the fingers. When J. was four hours old he firmly clasped a finger which was placed in the palm of his hand.[1] On R.’s second day, when his cheek was lightly touched, his right hand made a quick and strong movement toward the face as if to remove the disturbance. A light touch of J.'s forehead while the child was asleep caused, on the second day, the arms to fly up convul-}}
  1. ↑ In this first clasping, the thumb did not play a part, merely resting lightly against the second joint of the fore-finger. Clasping with the thumb contraposed, in the case of J., was established by the middle of his fourth month.
This article is issued from Wikisource. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.