Development of autonomy: role of walking onset and its timing.

The observations of psychoanalytically oriented clinicians such as Mahler, Pine, and Bergman and Greenacre were descriptive of intriguing aspects of the infant's transition to upright locomotion. Yet, research on how walking creates changes in the infant and in the family have scarcely been studied. In this naturalistic home study, 46 infants were designated "earlier" (13 girls and 10 boys) and "later" (12 girls and 11 boys) walkers based on their relative timing of entry into this developmental transition. Analyses between these two groups were done with age held constant and indicated that the earlier walkers showed a greater rise in autonomous functioning across the transition to self-produced, upright locomotion. Autonomy was assessed as infant proximity-seeking and distancing with respect to mother and "testing of wills" between mother and child. These findings suggested that the timing of beginning to walk crucially affects the development of autonomy. In addition to these clear differences associated with the walking transition, there were differences between the two groups in an aspect of temperament, Distress to Limitations, even prior to walking onset as well as at all time points of measurement.