The ability to respond emotionally is present in the newborn. It is a part of developmental process and not learned. Emotion is governed by "biological clock" of the brain and its maturation. The environment and its influences at different times can alter the emotional development in children.
The Swiss Psychologist, Jean Piaget (1970, 1972) took a different approach from that of the psychometricians to understand human cognition.
Public expenditure whether plans or non-plan or capital or revenue can also be classified into developmental and non-developmental expenditure.
Child psychology is a part of the developmental psychology, as it studies the growth and development of the child from conception till adolescence. Studying the child is helpful for understanding adult behaviors, as most of the adult personality and behaviors are the results of childhood experiences