Final answer:
An infant develops self-concept around 18 months, when they can recognize themselves in a mirror, demonstrated in the 'mirror test'. Mead's theory outlines a developmental path involving imitation and understanding of societal roles, culminating in self-awareness. Development of object permanence and stranger anxiety also reflect growing self-awareness.
Step-by-step explanation:
Development of Self-Concept
When an infant realizes the person in the mirror is himself, he has developed self-concept. Self-concept is the understanding of who one is, and it's a fundamental psychosocial milestone in childhood development. Considering the Amsterdam study mentioned, this developmental phase is usually identified around 18 months of age using the 'mirror test'. During this test, toddlers recognized a mark – such as a red dot of paint – on their nose and touched their reflection accordingly, demonstrating self-recognition. As they reach 24-36 months of age, children's ability to identify themselves in pictures further strengthens this self-awareness.
Furthermore, George Herbert Mead's theory highlights the stages through which children develop self-awareness and the generalized other. Initially, children mimic parents and caregivers, and gradually, they start to understand others' roles and societal norms. This culminates in the development of the generalized other, where children begin to grasp how they are perceived by broader society, forming a sense of self.
Another aspect of developing self-concept in infants includes understanding object permanence and exhibiting stranger anxiety. Both of these signify cognitive advancements where the child begins to comprehend persisting objects, even when not visible, and shows fear towards unfamiliar individuals, respectively. These developments contribute to the wider framework of an infant's growing awareness of themselves and their environment.