Theories of Development

Erikson’s theory is useful because it addresses both personality stability and personality change. To some degree, personality is stable, because childhood experiences influence people even as adults. However, personality also changes and develops over the life span as people face new challenges. The problem with Erikson’s theory, as with many stage theories of development, is that he describes only a typical pattern. The theory doesn’t acknowledge the many differences among individuals.

Erikson’s Theory of Psychosocial Development
StageConflict FacedTypical Age RangeMajor Challenge(s)
1Trust vs. mistrustFirst year of lifeHaving basic needs met, attaching to people
2Autonomy vs. shame and doubt1–3 yearsGaining independence
3Initiative vs. guilt3–6 yearsActing in a socially responsible way
4Industry vs. inferiority6–12 yearsCompeting with peers, preparing for adult roles
5Identity vs. role confusionAdolescenceDetermining one’s identity
6Intimacy vs. isolationEarly adulthood Developing intimate relationships
7Generativity vs. self-absorptionMiddle adulthoodBeing productive
8Integrity vs. despairOld ageEvaluating one’s life

Piaget’s Theory of Cognitive Development

While conducting intelligence tests on children, Swiss psychologist Jean Piaget began to investigate how children think. According to Piaget, children’s thought processes change as they mature physically and interact with the world around them. Piaget believed children develop schema, or mental models, to represent the world. As children learn, they expand and modify their schema through the processes of assimilation and accommodation. Assimilation is the broadening of an existing schema to include new information. Accommodation is the modification of a schema as new information is incorporated.

Example: Suppose a young boy knows his pet parrot is a bird. When he sees a robin outside and calls it a bird too, he exhibits assimilation, since he broadened his bird schema to include characteristics of both parrots and robins. His bird schema might be “all things that fly.” Now suppose a bat flaps out at him one night and he shrieks, “Bird!” If he learns it was a bat that startled him, he’ll have to modify his bird schema to “things that fly and have feathers.” In modifying his definition, he enacts accommodation.

Piaget proposed that children go through four stages of cognitive development:

Stage 1: Sensorimotor Period

In this stage, which lasts from birth to roughly two years, children learn by using their senses and moving around. By the end of the sensorimotor period, children become capable of symbolic thought, which means they can represent objects in terms of mental symbols. More important, children achieve object permanence in this stage. Object permanence is the ability to recognize that an object can exist even when it’s no longer perceived or in one’s sight.

Example: If a three-month-old baby sees a ball, she’ll probably be fascinated by it. But if someone hides the ball, the baby won’t show any interest in looking for it. For a very young child, out of sight is literally out of mind. When the baby is older and has acquired object permanence, she will start to look for things that are hidden because she will know that things can exist even when they can’t be seen.

Stage 2: Preoperational Period

This stage lasts from about two to seven years of age. During this stage, children get better at symbolic thought, but they can’t yet reason. According to Piaget, children aren’t capable of conservation during this stage. Conservation is the ability to recognize that measurable physical features of objects, such as length, area, and volume, can be the same even when objects appear different.

Example: Suppose a researcher gives a three-year-old girl two full bottles of juice. The girl will agree that they both contain the same amount of juice. But if the researcher pours the contents of one bottle into a short, fat tumbler, the girl will then say that the bottle has more. She doesn’t realize that the same volume of juice is conserved in the tumbler.

Piaget argued that children are not capable of conservation during the preoperational stage because of three weaknesses in the way they think. He called these weaknesses centration, irreversibility, and egocentrism:

  • Centration is the tendency to focus on one aspect of a problem and ignore other key aspects. In the example above, the three-year-old looks only at the higher juice level in the bottle and ignores the fact that the bottle is narrower than the tumbler. Because of centration, children in the preoperational stage cannot carry out hierarchical classification, which means they can’t classify things according to more than one level.
  • Irreversibility is the inability to mentally reverse an operation. In the example, the three-year-old can’t imagine pouring the juice from the tumbler back into the bottle. If she poured the juice back, she’d understand that the tumbler holds the same amount of liquid as the bottle.
  • Egocentrism is the inability to take someone else’s point of view. Animism, or the belief that even inanimate objects are living, results from egocentrism. Children assume that since they are alive, all other things must be too.
Stage 3: Concrete Operational Period

From the age of seven to about eleven, children become capable of performing mental operations or working through problems and ideas in their minds. However, they can perform operations only on tangible objects and real events. Children also achieve conservation, reversibility, and decentration during this stage:

  • Reversibility is the ability to mentally reverse actions.
  • Decentration is the ability to focus simultaneously on several aspects of a problem.

Furthermore, children become less egocentric during this stage as they start to consider simultaneously different ways of looking at a problem.

Stage 4: Formal Operational Period

In this stage, which begins around eleven years of age and continues through adulthood, children become capable of applying mental operations to abstract concepts. They can imagine and reason about hypothetical situations. From this point on, people start to think in abstract, systematic, and logical ways.

Critiques of Piaget’s Theories

Although Piaget made important contributions to the research on cognitive development, his theory has come under attack for several reasons:

  • Recent research has shown that he greatly underestimated children’s capabilities. For example, researchers have shown that babies achieve object permanence much sooner than Piaget said they do.
  • Children sometimes simultaneously develop skills that are characteristic of more than one stage, which makes the idea of stages seem less viable.
  • Piaget ignored cultural influences. Research has shown that children from different cultures tend to go through Piaget’s stages in the same order, but the timing and length of stages vary from culture to culture.
  • Some people never develop the capacity for formal reasoning, even as adults.
Piaget’s Theory of Cognitive Development
StageAgeImportant Features
1SensorimotorFirst two years of lifeObject permanence, symbolic thought
2Preoperational2–7 yearsCentration, irreversibility, egocentrism, and animism
3Concrete operational7–11 yearsReversibility, decentration, decrease in egocentrism, conservation
4Formal operational11 through adulthoodAbstract thought

Kohlberg’s Theory of Moral Development

Lawrence Kohlberg focused on moral reasoning, or why people think the way they do about right and wrong. Influenced by Piaget, who believed that moral reasoning depends on the level of cognitive development, Kohlberg proposed that people pass through three levels of moral development. He divided each level into two stages.

Level 1: The Preconventional Level

At this level, children ascribe great importance to the authority of adults. For children in the first stage of this level, an action is wrong if it’s punished, whereas in the second stage, an action is right if it’s rewarded.

Level 2: The Conventional Level

In the next level, children value rules, which they follow in order to get approval from others. In the first stage of this level, children want the approval only of people who are close to them. In the second stage, children become more concerned with the rules of the broader society.

Level 3: The Postconventional Level

In the final level, people become more flexible and consider what’s personally important to them. In the first stage of this level, people still want to follow society’s rules, but they don’t see those rules as absolute. In the second stage, people figure out right and wrong for themselves, based on abstract ethical principles. Only a small proportion of people reach this last stage of moral reasoning.

Critiques of Kohlberg’s Theories

Research supports key parts of Kohlberg’s theory. People do tend to progress in order through Kohlberg’s stages, and cognitive and moral development do affect each other. However, critics of Kohlberg’s theory have two main concerns:

  • People often show the reasoning characteristic of several different levels simultaneously. For instance, in one situation, a person might reason as if he is at a conventional stage, and in another situation, he might use reasoning typical of a postconventional stage.
  • Kohlberg’s theory of moral development favors cultures that value individualism. In other cultures, highly moral people may base their reasoning on communal values rather than abstract ethical principles.
Kohlberg’s Theory of Moral Development
LevelStageWhat Determines Right and Wrong
1.Preconventional1Punishment by adults
2Reward by adults
2.Conventional3Rules set by close people
4Rules set by society
3. Postconventional5Rules set by society, judged by what’s personally important
6Rules based on abstract ethical principles