Time in action
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WHEN we look at infants younger than three months of age our impression is that their movements lack proper coordination. When they move their arms and legs they seem to be flailing about, attempting, perhaps, to gain control over their movements as they adjust to their newly found gravity (Hopkins and Prechtl 1984; Prechtl and Hopkins 1986). For this reason, in part, developmental studies have traditionally argued that body schemas (understood as mechanisms of motor control) are absent at birth, and that their development depends on prolonged experience. Video studies, however, have shown that there is more organization in these movements than the casual glance reveals. Close to one-third of all arm movements resulting in contact with any part of the head lead to contact with the mouth, either directly (14%) or following contact with other parts of the face (18%) (Butterworth and Hopkins 1988; Lew and Butterworth 1995). Moreover, a significant percentage of the arm movements that result in contact with the mouth are associated with an open or opening mouth posture, compared with those landing on other parts of the face. In these movements the mouth anticipates arrival of the hand.1 This kind of coordination can be traced to even earlier points in development. Ultrasonic scanning on fetuses shows that similar hand-mouth movements occur between 50-100 times per hour from 12 to 15 weeks gestational age (DeVries, Visser and Prechtl 1984).2 This suggests that a basic hand-mouth coordination may be an aspect of early, centrally organized and organizing processes that come to involve proprioceptive input even prior to birth.
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