Final answer:
The primary psychosocial milestone of childhood is the development of a positive self-concept. Starting from around 18 months, toddlers recognize their reflections, beginning the journey of self-awareness. As they grow, they assert their independence and, during the preschool stage, learn to initiate activities that foster self-confidence and a sense of purpose.
Step-by-step explanation:
The primary psychosocial milestone of childhood is the development of a positive self-concept, which is an understanding of who they are. This crucial stage of early childhood development essentially refers to how children come to recognize themselves as distinct individuals with their own set of thoughts, feelings, and abilities. From infancy, when a baby can't recognize themselves in a mirror, to around 18 months when a toddler will begin to recognize that the reflection they see is themselves, as identified by the mirror test.
During the toddler years (ages 1-3 years), the focus is on resolving autonomy versus shame and doubt. This is often referred to as the 'me do it' stage, where toddlers assert their independence through personal choices, like selecting clothes to wear, which helps shape their self-concept and sense of autonomy.
As children reach the preschool stage (ages 3-6 years), they further develop their self-concept as they learn to initiate activities and assert control through social interactions and play. Erik Erikson's theory points to the task of initiative versus guilt where successful navigation results in self-confidence and a feeling of purpose.