- Infants followed from birth to 8 month, USA, 196?
- N = 24
- Non Response:
- 46% unattainable.
Mailed questionnaire and peerratings
- Authors's label
- Our Classification
- Examination by psychologist. Rated on 9-point scale (Activity: 'inactive -
vigorous' rating scale, from Bayley Infant Behaviour Profile).