This subject explores the cognitive, emotional and social changes people undergo as they pass through the entire life span. To what extent is the infant the parent of the child, and the child the parent of the ageing adult?
The Developmental Psychology is mainly concerned with the slow mental and physical changes in children and adolescents over time, but it also embraces the entire life span from conception to the mental and physical changes of old age.
It is typical of theory in developmental psychology to reckon time in terms of stages, where a stage has its own qualitative characteristics, and it cannot be skipped. Stages are a kind of ‘evolution’ applied to the individual, and may indeed have their origins in Charles Darwin’s theory of evolution.
No matter what aspect of development is under investigation, physical, learning, emotion, cognition, personality or social, stages are usually at least implied. Sigmund Freud proposed the first formal stage theory of character development. Given there are so many aspects to development, it is not surprising that the field breaks down into sub-specialties.
In addition, within the area of child psychology, psychologists are interested in special problem areas such as mental retardation and autism. Child psychologists sometimes work as school psychologists, which can be considered a sub-field in its own right and is also related to clinical psychology. They deal with the behavioural problems which may affect the learning of students in the school system. At the other end of the age scale are those who study disorders of old age, such as Alzheimer’s disease.
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