Temperament, Environment, and Six-Month Cognitive-Intellectual Development: A Test of the Organismic Specificity Hypothesis

The major question asked in the present study was whether temperamental differences mediated the infants' response to the early environment (organismic specificity). A corollary question involved the nature of the relationship between temperament and cognitive-intellectual development. Subjects were 100 six-month-old infants who were observed in their homes three times over a three-week period. Home observations were coded into social and physical environmental parameters. During this time period infant temperament and level of sensorimotor development were independently assessed. Canonical and univariate analyses revealed the following relationships: (1) Infants classified as temperamentally "easy" were more sensitive to environmental parameters than temperamentally "difficult" babies; when environmental influences were relevant for "difficult" infants, they tended to have a negative impact upon development. (2) Temperamental characteristics associated with difficultness were also associated with an inability to coordinate specific sensorimotor schemes. Implications of the above for our understanding of early environmental action were discussed.