H567/02 Section B - Developmental psychology

Explaining change across development

Developmental psychology studies how behaviour and psychological processes change over the lifespan.

Childhood is important, but development is not confined to children. Maturation involves biologically guided changes as an organism grows; learning involves changes associated with experience. These can interact: developing capacities influence what a child can learn, and opportunities to practise influence how those capacities are used. An age difference alone does not identify which process produced it.

Development may be described as continuous change or as stages. A stage theory proposes qualitatively different ways of functioning, rather than simply doing the same thing faster. Kohlberg's stages, for example, concern the reasoning used to justify moral choices, not a score for how “good” a child is. Different people may progress at different rates, and a theory of ordered stages does not require everyone to reach the final stage.

A longitudinal design follows the same people over time, making individual change visible. A cross-sectional design compares different age groups at one period, making an age comparison quicker. However, cross-sectional differences can also reflect cohort or experience differences, while longitudinal research can lose participants or change their responses through repeated testing. These Component 01 design principles matter because a developmental conclusion must be supported by evidence of change, not merely an age label.

Learning, reasoning and cultural experience

Developmental evidence can reveal both environmental influences and changes in the organisation of thought.

Bandura et al. (1961) exposed young children to aggressive or non-aggressive adult models, with a control group, then observed behaviour in a different setting without the model. Children who saw an aggressive model showed more imitation of that model's physical and verbal aggression. This illustrates acquisition of behaviour through observation during childhood. It does not establish that every observed act becomes a lasting adult trait: the measured outcome was behaviour in a short, structured situation.

Chaney et al. (2004) examined young children's use of a conventional asthma spacer and then a Funhaler with incentive toys. Parent reports indicated improved adherence with the Funhaler. The developmental link concerns how a child's behaviour can be influenced by an age-appropriate learning environment. It is not evidence that chronological age alone caused the improvement, or that the study followed the children into adulthood.

Kohlberg (1968) used moral dilemmas and longitudinal observations to investigate changes in boys' moral reasoning. His proposed sequence moves from reasoning focused on personal consequences towards conventional expectations and, for some, more general ethical principles. Repeated observations support claims about the order of change better than a single age comparison, although the original male sample limits a universal account.

Lee et al. (1997) compared Chinese and Canadian children of different ages using stories about deeds and truth-telling or lying. With increasing age, Chinese children's ratings became more favourable towards denying their own prosocial act, consistent with modesty norms; the pattern differed from Canadian children's. Culture and age therefore need to be considered together. This challenges a simple account in which development expresses the same moral values everywhere. Because different age groups were compared, the study does not directly track each child's changing judgements.

Judging a developmental account

Developmental research gains explanatory power when it identifies both the change and the conditions under which it occurs.

A strength is the ability to challenge adult assumptions about children. Bandura demonstrated that observed behaviour could be reproduced without the model remaining present; Chaney showed how a learning-based device could make a difficult routine more engaging. Such findings help adults change the environment instead of assuming an unwanted behaviour is fixed or deliberate.

Longitudinal evidence is another strength. Tracking the same participants allows changes in reasoning to be related to earlier responses rather than inferred from unrelated groups. In Kohlberg's work this supports investigation of a proposed sequence. Nevertheless, repeated interviews may influence familiarity with dilemmas, and participant loss can leave a less representative group. Consistency over time does not remove sampling or measurement problems.

A weakness of a universal stage account is that the chosen measure can privilege particular cultural values. Lee's findings show why denying credit for a good deed can carry a different meaning in different settings. Treating one community's judgement as a universal developmental standard could misclassify culturally learned modesty as immaturity. Research across cultures can refine a theory, but two national samples still do not represent every culture or every member of either country.