The structure of temperamental fear and pleasure in infants: a psychometric perspective.

Despite the prominence of temperament constructs in the study of infant development, little evidence exists about the internal structure of temperament. We assessed temperament both via questionnaire and in repeated laboratory visits for 168 9-month-old twins and singletons. Mothers' and fathers' agreement on temperament questionnaire scales was low, except for scales tapping negative emotionality and activity level. The factor structure of mothers' and fathers' questionnaire scales also differed, with fathers tending to associate higher motoric activity with hedonically positive behaviors. We measured fearfulness during 2 visual cliff episodes and a stranger approach, and we measured joy/pleasure during a series of 4 games. For both fearfulness and pleasure we found moderate cross-situation generality, short-term stability, and convergence with specific temperament questionnaire scales. Parameters of response, such as latency, duration, and intensity, intercorrelated within--but not across--response types. Fearful distress and avoidance proved to be uncorrelated. The results suggest that the component behaviors of infant fearfulness and pleasure are structured in a fashion consistent with a temperamental interpretation.