During which stage of social and emotional development do children begin to…

Concept: Social and emotional development is described as a sequence of age-graded stages, and conscience is one of its milestones. Conscience means holding an internal standard of right and wrong and recognising that behaviour produces outcomes. It can only begin once a child has enough symbolic thought and language to keep an adult rule in mind when the adult is not present, and a stable enough self-concept to measure its own act against that rule.

Application: Applying that principle to the stages named here:

1. Between about 3 and 6 years, symbolic thought and rapid language growth let a child represent an adult rule internally and recall it on its own.

2. The self-concept stabilises in the same window, so the child can compare an act with that internalised rule. The self-conscious emotions of pride and guilt, which first stir near the end of the second year, now attach to that adult standard rather than to bare success or failure.

3. Erikson names this period initiative versus guilt: the child acts on plans of its own and feels guilt when those plans run against adult standards.

4. Kohlberg places the same years at the pre-conventional level, where an act is judged by the outcome that follows it, which is precisely the link between an action and its consequence described in the question.

5. The milestone in the question therefore belongs to early childhood, roughly 3 to 6 years.

Cross-check: The other stages named do not mark the beginning of this milestone:

• Infancy, birth to about 2 years: behaviour is regulated by the caregiver rather than by any internal rule, and the achievement of the period is attachment and basic trust.

• Middle childhood, about 6 to 11 years: the moral sense is already in place and is being refined, with rules negotiated among peers and intention weighed against outcome. That is refinement, not a beginning. Some parenting and school-readiness checklists describe school-age children as still acquiring moral judgement; that description refers to this continued refinement rather than to the first appearance of the sense.

• Adolescence, about 12 to 18 years: moral reasoning turns abstract and principled and values are tested against personal identity, which is the latest of the four periods and long after this milestone starts.

Result: A sense of right and wrong, and the understanding that actions have consequences, begin to develop in early childhood.