Final answer:
Sullivan contends that peer relationships contribute to the social development of a child by fostering skills such as reciprocity, mutual respect, and equality. The correct domain of development related to Sullivan's description is social development, which is shaped by personal interactions and influences from the broader society.
Step-by-step explanation:
Harry Stack Sullivan, an American psychiatrist, contends that peer relationships are crucial for social aspects of a child's development. These relationships foster skills such as reciprocity, mutual respect, and equality. Given Sullivan's emphasis on interaction with peers and the formation of respectful relationships leading to proper functioning within a society, the correct option to describe this domain of development is b) Social development. Psychosocial development, including social and emotional development, emphasizes the importance of forming healthy attachments. Developmental psychologists explore the role of parent-child relationships, the effect of neglect, and the reasons behind different attachment styles in infants. Transitioning from parent-focused interactions, peers become a primary influence on individuals' development during adolescence, shaping their social behaviors and norms.