Objective: To chart the emergence of precursors and early signs of autism spectrum disorder (ASD) and autistic traits in the Avon Longitudinal Study of Parents and Children, a prospective longitudinal cohort study of the surviving offspring of 14,541 pregnant women from southwestern England with an expected delivery date between April 1991 and…

The purpose of the study was to establish dimensions of functioning accounting for interindividual variation in behavior in the later infancy period and to investigate the stability of the dimensional structure during the infancy period. Factor analyses were performed on parent questionnaire data for 357 infants, aged 11 to 15 months. An 8-factor…

The purpose of this study was to apply factor analysis techniques to delineate dimensions of early infant behavior and to establish categories of functioning which can be seen as a source of individuality in early childhood. Data about the behavior of 791 infants in two age groups (11-25 weeks and 26-41 weeks) were obtained using a questionnaire…

The influence of age, sex, representational detail of objects (prototypicality) and adult play suggestions on children's progression of pretend behaviors was studied. A checklist was developed and utilized for coding the responses of 20 children (10 males, 10 females), to objects judged to be high and low prototypical by 12 adults. Children ranged…

Factor analysis of 25 rating scales from Bayley's infant behavior record were performed for a sample of about 300-400 infant twins tested one or more times between 3 and 24 months of age. The analyses provided five major and two minor factors that were considerably consistent at all ages. (Author/DB)