What influences psychological development?

Psychological development means patterned change and continuity in thinking, feeling and relating to other people. Cognitive development concerns processes such as reasoning, attention and understanding. Emotional development involves identifying, expressing and regulating feelings. Social development concerns relationships, social understanding and participation. These aspects interact: learning language can help a child explain frustration, while supportive relationships can create opportunities to practise that language. Development continues through adolescence and adulthood.

It should not be described as a ladder on which every person must move at the same rate.

Hereditary influences are characteristics transmitted biologically between generations. Environmental influences include experiences and conditions before and after birth, such as opportunities to learn, family relationships and cultural practices. An interaction occurs when the effect of one influence depends on another. A predisposition does not guarantee an outcome, and an environmental association does not establish that experience alone caused a difference. Research comparing groups must consider differences in both their characteristics and circumstances.

Avoid treating an individual difference as proof of a single genetic cause.

A lifespan explanation identifies what changed, which developmental aspects are involved and what evidence could distinguish competing explanations. Age may describe when a difference appears, but age itself is not a complete mechanism. A comparison between different age groups can also reflect cohort experiences. Following the same people over time provides another kind of evidence, although participants may withdraw and repeated testing may influence performance.