Continuity of personality patterning from 3 to 15 years in a longitudinal sample

A longitudinal sample of 97 subjects was rated at 3, 7, 11 and 15 years on variables selected as indices of Extraversion-Introversion (EI) and Neuroticism (N) or emotionality. Principal factor analysis and Varimax rotation were performed at each age. Continuity of patterning of the variables across the four ages was determined before, and after, rotation of the items to maximal contiguity by Kaiser's method. Two principal factors, clearly identifiable as EI and N, displayed very high continuity, as did 45 rotated factors, according to Gray's model. Four Varimax factors, which initially appeared dissimilar at different ages, were shown to display high continuity, in terms of loadings on standard reference axes, after alignment of the item vectors. Thus the inadequacy of simply comparing factors as they happen to emerge, was clearly demonstrated.