A person in psychotherapy is just as much involved in personal development as is the child. The whole of personal construct psychology is based upon the fundamental idea that a person’s psychological processes are channelled by the ways in which he or she successively construes events. Many of the examples G. A. Kelly uses in his major work are to do with the construing of children. But no comprehensive application of the psychology of personal constructs to the development of construing systems is yet available, although beginnings can be seen in S. R. Jackson and Don Bannister. P. Salmon further points out that J. Piaget’s theoretical model is primarily concerned with the development of thinking about the physical world and has relatively little to say about the development of the person qua person. Both behavioural and personality constructs increased in number with age and all others decreased except for kinship constructs, which showed no variation.