Final answer:
The first stage of a child's psychosocial development is the trust versus mistrust stage, according to Erik Erikson's psychosocial theory.
Step-by-step explanation:
The first stage of a child's psychosocial development, according to Erik Erikson's psychosocial theory, is the trust versus mistrust stage. This stage occurs during infancy, from birth to 12 months. During this stage, infants develop a sense of trust if their caregivers are responsive and meet their needs.