Independent Dimensions of Hyperactivity and Aggression: A Validation With Playroom Observation Data
Dr. Milich was at the University of Iowa when the article was originally published.
Data are offered that examine the validity of the two-factor solution (Hyperactivity and Aggression) originally presented by Loney, Langhorne, and Paternite (1978) for symptom data from a sample of 135 hyperkinetic/minimal brain dysfunction (HK/MBD) boys. In contrast to the Loney et al. study, the present sample (TV = 90) consisted of consecutive male referrals to an outpatient child psychiatric service. Replication and further validation of the Hyperactivity and Aggression factors are examined through hierarchical multiple regression analyses performed on demographic data, mother and teacher rating scales, and observations made in two 15-minute playroom procedures (free play, restricted - academic). The results,' in general, support the validity of the differentiation of these two externalizing dimensions. The Hyperactivity factor made a unique contribution in accounting for the variance of numerous dependent variables, beyond the variance it shared with the Aggression factor. In contrast, the Aggression factor made a unique contribution to few of these variables. In no case was the information supplied by the two symptom factors completely redundant.