AFFECTIVE REORGANIZATION IN THE INFANT, THE MOTHER, AND THE DYAD - THE ROLE OF UPRIGHT LOCOMOTION AND ITS TIMING

Clinical theory is replete with rich observations that the onset of wa lking engenders an enhancement of emotional expression in the infant. Yet, no empirical research exists on this subject. Moreover, the impor tance of normal timing variations in the onset of developmental transi tions has not been a topic of investigation in most developmental rese arch. In this naturalistic home study, ''earlier'' and ''later'' walki ng groups were delineated on the basis of timing of entry into this de velopmental transition. Age-held constant analyses indicated that earl ier walkers and their mothers generally showed a rise in positive exch anges as well as ''testing of wills'' across the transition to walking . These changes were less clear for the later walkers. Differences wer e observed also between the two groups even prior to walking. These fi ndings suggest that future studies should take account of timing varia tions in the onset of a developmental transition.