The behavioral development of rural Guatemalan infants was assessed shortly after birth on a Neonatal Assessment Scale (NAS) and at 6-, 15-, and 24-months-of-age on a Composite Infant Scale (CIS). Summary variables based on NAS performance poorly predicted later assessed performance even as recently as six months after birth. The CIS modestly…

The popular view among American psychologists has been that there is a continuity of psychological structure that is shaped by early experience. Data gathered in studies of Guatemalan villages imply serious discontinuities in the development of particular cognitive competencies and capacities for affect through preadolescence. The first two years…