Final answer:
Children's self-concept stability increases due to the development of autonomy, favorable comparisons with peers, the formation of a more complex self-identity during adolescence, and the development of a sophisticated cognitive framework, as proposed by developmental theories and Erikson's psychosocial stages.
Step-by-step explanation:
The increasing stability of a child's self-concept over time can be explained by several developmental processes. In early stages, toddlers begin to develop autonomy and a sense of self through recognizing themselves, as seen through the mirror test. As they grow, children learn to compare themselves to others, with favorable comparisons reinforcing a sense of competence and motivation. Erikson's stages of psychosocial development highlight that during adolescence, individuals re-evaluate their self-concept as they form an identity, cementing their notion of self through internalizing messages about their strengths and weaknesses.
Developmental theories by Piaget emphasize how children develop and adjust their schemata, mental models to understand the world, through assimilation and accommodation. This cognitive framework becomes more complex and stable as they mature. Furthermore, through social interactions, children start to understand the generalized other, which represents societal behavioral expectations, further solidifying their self-concept.
As children transition through cognitive, physical, and psychosocial domains, their self-concept becomes increasingly stable, influenced by their experiences, socialization, and innate developmental trajectory across the lifespan.