During which stage do infants primarily know the world through sensory impressions and motor activities?

The correct choice is the sensorimotor stage, which is the first stage in Jean Piaget's theory of cognitive development. During this stage, which spans from birth to about 2 years of age, infants engage with the world primarily through their senses and motor actions. This means they learn by looking, touching, sucking, and grasping, essentially exploring their environment through direct physical interaction. It is during this time that they develop important concepts such as object permanence, the understanding that objects continue to exist even when they cannot be seen.

In contrast, the other stages represent different developmental milestones. The preoperational stage follows the sensorimotor stage and involves the development of language and symbolic thinking, but it still lacks the logical reasoning characteristic of later stages. The concrete operational stage, which comes after preoperational, is marked by the beginning of logical thought about concrete objects but still lacks abstract reasoning. Finally, the formal operational stage involves the capacity for abstract thought and hypothetical reasoning, which is not present in infants at the sensorimotor stage.