A naturalistic home study delineated earlier and later walking groups. Age-held constant analyses indicated that earlier walkers and their mothers generally showed a rise of positive exchanges as well as a testing of wills across the transition to walking. Changes were less clear for the later walkers, and differences were also observed between…

Reviews bases for contemporary discontinuity theories of mental development, presents findings that support alternative proposition of continuity and scrutinizes assessment methods from which these continuity results derive. Also offers several models that help explain the continuity findings, and argues that individual differences in mental…