The study and measurement of abilities in young children has been a field of early and continuing interest in psychology. Within this field it is possible to discern several major areas of inquiry. In attempting to draw up a schema of sorts it can be seen, first of all, that there have been many studies which broadly fall into the category of ' Developmental '. These studies have dealt with aspects of child development such as physical growth, motor development, perceptual development and so on (e.g. Birch & Lefford, 1967; Brozek, 1970; Gliner, Pick, Pick & Hales, 1969). Secondly, there have been what might be called 'Social Development ' studies, concerned with acquisition of various behaviours such as communication skills necessary for harmonious group behaviour, and the learning of appropriate roles (e.g. Baldwin, Baldwin, Hilton & Lambert, 1969; Selman, 1971). Many of these studies have been influenced by theories and investigations of ' personality development ' in children, particularly the ' child rearing ' studies (e.g. Ritchie & Ritchie, 1970; Sears, Maccoby & Levin, 1957; Whiting and Child, 1953). More recently there have been systematic observational studies of interaction patterns between children and significant others in their milieu.