Final answer:
Jean Piaget emphasized that a child's cognitive development is greatly influenced by their interaction with the physical and the social environments, involving a continuous interplay between their sensory experiences, motor behaviors, and social learning from family and others.
Step-by-step explanation:
For optimal cognitive development, Jean Piaget stressed the importance of a child's interaction with the physical environment and the social environment. Piaget's theory of cognitive development underscores that children learn about the world around them through sensory experiences and motor behaviors, a process that takes place from birth through age 2, known as the sensorimotor stage. As social beings, children also develop cognitive abilities through interactions with family members, such as parents and grandparents, who are the primary agents of socialization, teaching the child about various aspects of society and helping them differentiate between what is real and what is imagined. Additionally, Piaget believed that cognitive abilities develop in specific stages and that this development involves a negotiation between an individual's internal understanding of the world and their social experiences.