Factor structure of temperament in the third year of life.

The hypothesis that the nine dimensions of temperament defined by Chess and Thomas (1984) would emerge in a principal components analysis of maternal descriptions of 763 two-year-olds in a longitudinal study was not confirmed. The only component that bore any resemblance to the a priori dimensions of temperament proposed by Chess and Thomas was the sixth component--defining rhythmicity--in a Promax rotation. A higher order rotation to a two-factor solution produced components representing sociability and difficult behavior, respectively. It is argued that in the long term, these dimensions of temperament will, through the process of interaction with others, provide dimensions of personality identified by Hans Eysenck and his colleagues (1985).