Key theories in developmental psychology

Throughout our lifespans, we constantly grow and develop. From when we’re born, through to old age there are many milestones we hit in our psychological development.

What is developmental psychology?

Developmental psychology is the study of human development across the lifespan. It encompasses physical, cognitive, social, intellectual, perceptual, personality and emotional growth, and is key to understanding how we learn, mature and adapt.

Whilst many theories within developmental psychology focus on development during childhood, there are also prominent theories relating to early and late adulthood which look at how thinking, feeling, and behaving changes throughout a person’s life.

The key theories in developmental psychology were coined by Jean Piaget, John Bowlby, and Erik Erikson.

Jean Piaget: The Four Stages of Cognitive Development

Piaget’s child psychology theory, originally published in 1936, focuses on both how children acquire knowledge and on understanding the nature of intelligence. There are four stages, founded on the belief that children take an active role in the learning process and that new knowledge is built upon existing knowledge as children interact with the world around them, and that there is a fundamental change in how a child thinks about the world as opposed to what the child thinks about the world.

Before Piaget’s theory was published, it was believed that children were just smaller versions of adults. Piaget was one of the first to identify that a child’s thought process is different to that of an adult, and proposed that intelligence is something which grows and develops through a series of stages.

The sensorimotor stage – from birth to 2 years

In this earliest stage, children’s experiences occur through basic reflexes, senses and motor responses and they are constantly making new discoveries about how the world works through their movements and sensations. 

They learn object permanence, and discover that things continue to exist even though they can’t be seen, which Piaget believed to be an important element at this point of development, and learn that they are separate beings from the people and objects around them which allows them to begin to attach names and words to objects. During this stage, children also realise that their actions can cause things to happen in the world around them.

The preoperational stage – from 2 to 7 years

During the preoperational stage of child development, the emergence of language acquisition is one of the key features. Building upon the foundations of language development which were introduced in the sensorimotor stage, children begin to think symbolically and learn to use words and pictures to represent objects.

However, at this stage, Piaget suggested that children still tend to think in very concrete terms and they tend to be quite egocentric as they struggle with logic and the ability to see things from the perspective of others.

The concrete operational stage – from 7 to 11 years

Throughout the concrete operational stage, children begin thinking logically and in a more organised way despite still being concrete and literal. They also learn how to view other people’s point of view as the egocentrism from the preoperational stage starts to disappear.

Within this stage, children also understand that their thoughts, feelings and opinions are unique to them, and that not everyone will think and feel the same way they do.

The formal operational stage – from 12 years and up

The last stage of Piaget’s theory sees children develop an increase in logic, the ability to use deductive reasoning from a general principle to specific information, and an understanding of abstract thought and ideas. 

When moving into teenhood, individuals think more about moral, philosophical, ethical, social and political issues, and are more able to think about and plan for the future.

John Bowlby: Attachment theory

Originally focused on understanding the distress that children experience when separated from their primary caregivers, British psychologist John Bowlby was the first attachment theorist. His seminal work was published in 1969. The basis of this work was formed in the 1930s, when Bowlby worked as a psychiatrist in a Child Guidance Clinic in London and treated many emotionally disturbed children.

Bowlby believed there to be a link between early infant separations from their mother and later maladjustment, and proposed that attachment can be understood within an evolutionary context as a caregiver provides safety and security for a child, thus enhancing the child’s chance of survival.

As well as the attachment between a parent and child, this theory has been applied to other long-term relationships, particularly those between romantic partners as Bowlby suggested that the earliest bonds formed between a caregiver and a child can also impact emotional bonds throughout the child’s life.

There have been many research studies that have built upon Bowlby’s original attachment theory, most notable of which may be Mary Ainsworth’s ‘Strange Situation’ study where children between 12 and 18 months were observed as their mothers briefly left them alone and then returned. It was this study which described the three major styles of attachment: secure attachment, insecure-ambivalent attachment, and insecure-avoidant attachment.

Erik Erikson: Stages of Psychosocial Development

Erikson’s theory (1958, 1963) was impacted by the work of psychoanalyst Sigmund Freud, as he also believed that a person’s personality developed in a series of stages. Focused on the impact of social experiences throughout a lifetime, as opposed to Freud’s theory of psychosexual stages, Erikson was interested in how the development and growth of an individual is impacted by social interaction and relationships.

Each stage contains a conflict which Erikson suggested serves as a pivotal moment in development, and each stage builds on the one previous. If conflicts are resolved, Erikson believed a person will emerge from the stage with psychological strengths which will stay with them throughout their lifespan.

1. Trust vs. Mistrust – from birth to 18 months

During this stage, an infant looks to their primary caregiver for stability and consistency of care. If the care is consistent, predictable, and reliable, the infant will develop a sense of trust. If the care needs are not met, the infant may develop mistrust, suspicion and anxiety. 

The outcome of this conflict is hope.

2. Autonomy vs. Shame and Doubt – from 2 to 3 years

Within this stage, children are focused on developing a sense of personal control over physical skills and a sense of independence. If children are encouraged and supported, they will become more confident and secure. If children are criticised, controlled, or not given the opportunity to assert themselves, they begin to feel inadequate, lack self-esteem, and feel a sense of shame and doubt in their abilities.

The outcome of this conflict is will.

3. Initiative vs. Guilt – from 3 to 5 years

This stage focuses on play and the development of initiative. If a child is met with criticism or control in their actions, or if a child’s questions are treated as trivial as their thirst for knowledge grows they may develop a sense of guilt, making them slow to interact with others and limiting their creativity.

The outcome of this conflict is purpose.

4. Industry vs. Inferiority – from 6 to 11 years

A child’s peer group gains greater significance during this stage. If they are encouraged and reinforced for their initiative, they feel confident in their abilities. If initiative is not encouraged or is restricted by caregivers or teachers, they may feel inferior.

The outcome of this conflict is competence.

5. Identity vs. Role Confusion – from 12 to 18 years

During this stage, an adolescent will examine their identity to find out who they are. Erikson suggested that two identities are involved: the sexual and the occupational. It includes a person growing into the changes of their body and feeling comfortable with them, and establishing a sense of identity within a society.

The outcome of this conflict is fidelity.

6. Intimacy vs. Isolation – from 19 to 40 years

This life stage is when relationships are explored, which can result in happy relationships, and a sense of commitment, safety, and care. Avoiding intimacy may result in feelings of isolation and loneliness, and mental health issues such as depression.

The outcome of this conflict is love.

7. Generativity vs. Stagnation – from 40 to 65 years

Generativity refers to a person making their mark on the world, through creating or nurturing things that will outlast them. This allows an individual to develop a sense of being part of a bigger picture, whether through raising children, being productive at work, or being involved in community activities.

The outcome of this conflict is care.

8. Ego Integrity vs. Despair – 65 to death

During this stage, a person will reflect on accomplishments and develop a sense of integrity if they believe they have lived a successful life. Those who reflect on their lives and regret not achieving their goals may experience feelings of bitterness and despair.

The outcome of this conflict is wisdom.

Learn more about developmental psychology

By studying a Master’s in psychology, you can learn more about developmental psychology and how changes differ between cultures and groups, as well as the ways our individual experiences shape how we see the world.

The University of Wolverhampton’s MSc Psychology is accredited by the British Psychological Society and is open to people with or without a psychology background.

Find out more about this part-time postgraduate psychology degree, and apply today.