Emergence and constructvalidation of the big five factors in early childhood: a longitudinal analysis of their ontogeny in Sweden.

Researchers have shown that the five major dimensions of personality (extraversion, agreeableness, conscientiousness, neuroticism, and openness to experience) and two additional factors (irritability and positive activity) are evident from adolescence. This study attempted to replicate and extend these results in a longitudinal study of 102 Swedish children, followed from 2.3 to 15.2 years of age. Item analyses revealed consistently reliable irritability, conscientiousness, and positive activity factors, whereas the internal reliability of the extraversion, agreeableness, neuroticism, and openness to experience factors increased over time. Irritability and positive activity were not independent of the other factors. Scores on most of the personality factors were fairly stable over time. Over time, children became less extraverted, more agreeable, and more conscientious. Neuroticism and openness to experience increased in Phase III, although openness then decreased in Phase V. Validity of the original factors was demonstrated by correlations with independent assessments of the children's cognitive performance and adjustment to school.