Infant positive and negative emotionality: One dimension or two?

To determine whether one or two dimensions of infant (positive and negative) emotionality best characterized infant functioning, parental reports (10 months) and elicited emotion (12-13 months) were examined. The adequacy of 1- and 2-latent-construct measurement models were evaluated and the model consisting of separate positive and negative dimensions proved to fit the data better. The discriminant validity of the 2-dimension model was evaluated. It was found that early positivity (12-13 months) predicted later positivity (18-20 months) better than later negativity, with the reverse being true of early negativity. Results are discussed in terms of prior work on infant and adult emotionality, and implications for the study of development are considered.