Is development due more to genetics or environment? Does development occur slowly and smoothly, or do changes happen in stages? Do early childhood experiences have the greatest impact on development or are later events equally important?

Here are some of the basic questions within the realm of developmental psychology and what many psychologists today believe about these issues.

Nature vs. Nurture

The debate over the relative contributions of inheritance and the environment usually referred to as the nature versus nurture debate is one of the oldest issues in both philosophy and psychology. Philosophers such as Plato and Descartes supported the idea that some ideas are inborn. On the other hand, thinkers such as John Locke argued for the concept of tabula rasa—a belief that the mind is a blank slate at birth, with experience determining our knowledge. Some aspects of development are distinctly biological, such as puberty. However, the onset of puberty can be affected by environmental factors such as diet and nutrition.

Early Experience vs. Later Experience

A second important consideration in developmental psychology involves the relative importance of early experiences versus those that occur later in life. Are we more affected by events that occur in early childhood, or do later events play an equally important role? Psychoanalytic theorists tend to focus on events that occur in early childhood. According to Freud, much of a child’s personality is completely established by the age of five. If this is indeed the case, those who have experienced deprived or abusive childhoods might never adjust or develop normally. In contrast to this view, researchers have found that the influence of childhood events does not necessarily have a dominating effect over behavior throughout life, however there is evidence that childhood adversity may correlate to greater levels of stress in adulthood. Many people with less-than-perfect childhoods go on to develop normally into well-adjusted adults.

Continuity vs. Discontinuity

A third major issue in developmental psychology is that of continuity. Does change occur smoothly over time, or through a series of predetermined steps? Other theories outline a series of sequential stages in which skills emerge at certain points of development. Most theories of development fall under three broad areas.

Psychoanalytic Theories

Psychoanalytic theories are those influenced by the work of Sigmund Freud, who believed in the importance of the unconscious mind and childhood experiences. Freud’s contribution to developmental theory was his proposal that development occurs through a series of psychosexual stages. Theorist Erik Erikson expanded upon Freud’s ideas by proposing a stage theory of psychosocial development. Erikson’s theory focused on conflicts that arise at different stages of development and, unlike Freud’s theory, Erikson described development throughout the lifespan.

Learning Theories

Learning theories focus on how the environment impacts behavior. Important learning processes include classical conditioning, operant conditioning, and social learning. In each case, behavior is shaped by the interaction between the individual and the environment.

Cognitive Theories

Cognitive theories focus on the development of mental processes, skills, and abilities. Examples of cognitive theories include Piaget’s theory of cognitive development.

Abnormal Behavior vs. Differences

One of the biggest concerns of many parents is whether or not their child is developing normally. Developmental milestones offer guidelines for the ages at which certain skills and abilities typically emerge, but can create concern when a child falls slightly behind the norm. Psychoanalytic theories are traditionally focused upon abnormal behavior, so developmental theories in this area tend to describe deficits in behavior. Learning theories rely more on the environment’s unique impact on an individual, so individual differences are an important component of these theories. Today, psychologists look at both norms and individual differences when describing child development.