Convergences and discrepancies, among mothers' and professionals' assessments of difficult neonatal behaviour.

The idea that difficult newborn behaviour reflects an inborn disposition was tested by comparing measures from different circumstances, occasions and observers. Correlations between researcher measures from separate settings and occasions were statistically significant but modest, indicating a "rudimentary" constitutional trait contribution to difficult newborn behaviour. Little evidence of a discrete subgroup of particularly difficult newborns was obtained. Maternal assessments were internally consistent but weakly explained by baby constitutional factors or nurses' reports. The importance of contextual and development variables is discussed. Alternative methodological strategies for studying constitutional and social-developmental contributions to difficult behaviour are needed.