Developmental Psychology

File photo. The Developmental Stages of a Child (Online Psychology Degree Guide, 2021)

Developmental psychologists study children’s development, and the development of human behavior across the lifespan, from a variety of different perspectives. Thus, if one is studying different areas of development, different theoretical perspectives will be important and may have influence over the ways psychologists and students think about, and study, development.

Using the developmental perspective, a psychologist might look at how memory functions in people of different ages. Without further practice, 3-month-old babies can retain for about a month the memory that kicking moves a mobile suspended above their crib. However, most adults have difficulty recalling events that occurred before the age of 3 or 5 years. Teens and young adults are able to remember names faster than are older adults.

In this introductory article we first discuss the role of age-related factors in affecting development. Then we describe different concepts of human development and human nature that have helped to shape people’s thinking about development.

Studying Changes with Age

The newborn infant is a helpless creature, with limited means of communication and few skills. By 18–24 months—the end of the period of infancyOpens in new window—all this has changed. The child has formed relationships with others, has learned a lot about the physical world, and is about to undergo a vocabulary explosion as language development leaps ahead. By the time of adolescenceOpens in new window the child is a mature, thinking individual actively striving to come to terms with a rapidly changing and complex society.

It is tempting to think that the many developments we find as childhood progresses are a result of age, but in this we must be careful.

Increasing age, by itself, contributes nothing to development. What is important is the maturation and changes resulting from experience that intervene between the different ages and stages of childhood: the term maturation refers to those aspects of development that are primarily under genetic control, and which are relatively uninfluenced by the environment. An example could be pubertyOpens in new window: although its onset can be affected by environmental factors, such as diet, the changes that occur are primarily genetically determinend.

With respect to environmental factors, we would not, for instance, expect a particular 4-year-old child to be more advanced in language development than a 2-year-old if, from the age of 2, the child had not been exposed to language at all.

The normal 4-year-old will have been exposed to a multiplicity of agents, forces and events in the previous two years, and will have had the opportunity actively to explore and experiment with the world.

Development psychologists study age-related changes in behavior and development, but underlying their descriptions of these changes is the clear understanding that increasing age by itself causes nothing, and so we always need to look for the many factors that cause development to take place.

Concepts of Human Development

The assumptions and ideas we have about human nature will affect how we rear our own children and how we interpret the findings from studies of children. Our implicit, lay or ‘folk’ theories of development often reflect the issues that psychologists investigate, with the aim of putting our understanding on a firmer, more scientific footing. We will begin by discussing two such views — ‘punishment or praise?’ — and then we will discuss some of the theoretical views that have influenced psychologists’ thinking about development.

‘Folk’ theories of development: Punishment or praise?

We all have theories and views on how children should be reared. These views result from our own upbringing, our peers’ experiences, our parents’ ideas, the media and many other sources.

These views will often influence how we bring up our own children and there is often intergenerational continuity of childcare practices. For example, there are several ways in which children become attached to their caregivers and these ‘styles of attachment’ may show continuity and stability across generations — from grandparents to parents to children (e.g., Benoit & Parker, 1994).

Here are two opposing views about the usefulness of physical punishment — see which one you agree with!

Spare the rod and spoil the child

The dauphin, Louis, was born to King Henri IV of France in 1601 (‘dauphin’ means the eldest son of the king, and he became King Louis XIII at the age of 9). The king wrote to Louis’ governess:

John Wesley (1703 – 91) was the founder of the religious Evangelical movement known as Methodism. He was the 15th of 19 children born to Samuel and Susanna Wesley. Here is part of a letter from Susanna Wesley (a woman of great piety) to her son John about how to rear children (cited in Sants & Barnes, 1985, p.24):

At that time infant morality was very high (why else have 19 children?), and Susanna Wesley’s views originate from a belief that children are born in a state of sin and it is therefore necessary to use all means to save their souls, almost from birth. A similar view was expressed by Theodore Dwight (1834, The Father’s Book) —‘No child has ever been (born) destitute of an evil disposition—however sweet it appears.’

All sweetness and light: Like begets like

Compare these views with the following: ‘Your baby is born to be a reasonable, friendly human being’ (Benjamin Spock, from his book Baby and Child Care, 1946, cited in Sants & Barnes, 1985). Spock’s book had a huge impact on American parents’ rearing of their children. Here is an extract from the famous poem ‘Children Learn What They Live’ by Dorothy Law Nolte:

In this and the previous section we have two opposing lay, or ‘folk’ theories about child rearing:

1. children need to be punished regularly in order to develop as pleasant, law-abiding citizens — failure to use harsh physical punishment carries with it the possibility, if not the certainty, that the child will grow up to be disobedient, and their very soul may be at risk;
2. the contrary view is that children are born inherently good, a view that carries the implication that the use of physical punishment might be unnecessary, perhaps even harmful.

We shall see later that research has given strong support to the latter view, but clearly the views and theories that parents and guardians have about child rearing will influence their own child-rearing practices.

In much the same way that parents will be influenced by their ‘folk’ theories, developmental psychologists will be influenced by their theoretical learnings (which are not always based on a fully objective appraisal of the evidence!), and we discuss two of the most important of these next.

Defining development according to world views

Psychologists, and others who study children’s development, also have different views of development. The manner in which development is defined, and the areas of development that are of interest to individual researchers, will lead them to use different methods of studying development. We will describe two such different views of development that have been offered by psychologists holding different world views.

The eminent developmental psychologist Richard Lerner defines a world view (also called a paradigm, model, or world hypothesis) as ‘a philosophical system of ideas that serves to organize a set or family of scientific theories and associated methods’ (1986, p. 42). They are beliefs we adopt, which are often not open to empirical test — that is, we simply believe them!

Lerner and others note that many developmental theories appear to fall under one of two basic world views: organismic and mechanistic. Only a superficial description of these two world views will be presented here.

Organismic world view

According to the organismic world view a person is represented as a biological organism that is inherently active and continually interacting with the environment, and therefore helping to shape its own development.

This world view emphasizes the interaction between maturation and experience that leads to the development of new internal, psychological structures for processing environmental input (e.g., Geldhof et al., 2015; Gestsdottir & Lerner, 2008).

As Lerner states: ‘The Organismic model stresses the integrated structural features of the organism. If the parts making up the whole become reorganized as a consequence of the organism’s active construction of its own functioning, the structure of the organism may take on a new meaning; thus qualitatively distinct principles may be involved in human functioning at different points in life.

These distinct, or new, levels of organization are termed stages . . . (p. 57). An analogy is the qualitative change that occurs when molecules of two gases, hydrogen and oxygen, combine to form a liquid, water.

Other qualitative changes happen to water when it changes from frozen (ice) to liquid (water) to steam (vapor). Depending on the temperature these qualitative changes in the state of water are easily reversed, but in human development the qualitative changes that take place are rarely, if ever, reversible — that is, each new stage represents an advance on the preceding stage and the individual does not regress to former stages.

The point is that the new stage is not simply reducible to components of the previous stage; it represents new characteristics not present in the previous stage. For example, the organism appears to pass through structural stages during foetal development.

In the first stage (Period of the Ovum — first few weeks after conception) cells multiply and form clusters; in the second stage (Period of the Embryo — two to about eight weeks) the major body parts are formed by cell multiplication, specialization and migration as well as cell death; in the last stage (Period of the Foetus) the body parts mature and begin to operate as an integrated system, for example, head orientation towards and away from stimulation, arm extensions and grasping, thumb sucking, startles to loud noises, and so on (Fifer, 2010; Hepper, 2011). Similar stages of psychological development beyond birth are postulated to occur as well.

Piaget is perhaps the best example of an organismic theorist. In brief, Piaget suggested that cognitive development occurs in stages and that the reasoning of the child at one stage is qualitatively different from that at the earlier and later stages.

The job of the developmental psychologist subscribing to an organismic viewpoint is to determine when (i.e., at what ages) different psychological stages operate and what variables, processes, and/or laws represent the differences between stages and determine the transitions between them.

Mechanistic world view

According to the mechanistic world view a person can be represented as being like a machine (such as a computer), which is inherently passive until stimulated by the environment. Ultimately, human behavior is reducible to the operation of fundamental behavioral units (e.g., habits) that are acquired in a gradual, cumulative manner.

According to this view the frequency of behaviors can increase with age due to various learning processes and they can decrease with age when they no longer have any functional consequence, or lead to negative consequences (such as punishment).

The developmentalist’s job is to study the environmental factors, or principles of learning, which determine the way organisms respond to stimulation, and which result in increases, decreases, and changes in behavior.

Unlike the organismic view development is reflected by a more continous growth function, rather than occurring in qualitatively different stages, and the child is passive rather than active in shaping its own development. Behaviorists represent this world view, and their views are discussed elsewhere.

Ways of Studying Development

Developmental psychologists have a variety of strategies with which to study development. These various strategies can be subdivided into two broad, interrelated categories — designs that enable us to study age-related changes in behavior, and the associated research methods that are used to collect the information or data about development. These are discussed under the next two broad headings — Designs for studying age-related changesOpens in new window and Research methods, which include observational studiesOpens in new window, experimental methodsOpens in new window, psychological testingOpens in new window, and correlational studiesOpens in new window.