Kicking, rocking, and waving: contextual analysis of rhythmical stereotypies in normal human infants.

I analysed the triggering contexts of over 14,000 bouts of rhythmical stereotypies of the legs, arms, and whole torso observed in 20 normal infants during their first year. Infant stereotypies were elicited by a wide variety of contexts including non-alert states, interactions with the caregiver and other persons, feeding situations, object interest, and kinaesthetic changes. The frequency of stereotypy in all contexts was a function of age. Non-alert states and interactions with the caregiver were disproportionately associated with leg and torso stereotypies. The relationship between these human stereotypies and the function and control of stereotyped behavior in other species is discussed.