Which statement best describes the sensorimotor substages as a group?

• A. They include reflexes up to coordination of tertiary reactions.
• B. They are the cognitive milestones in adolescence.
• C. They refer to language development in toddlers.
• D. They are unrelated to motor actions.

Answer: (A)

The sensorimotor substages describe how infants build knowledge through action, moving from reflexive behavior to purposeful, experimental interaction with the world. In this period—from birth to about two years—the child starts with natural reflexes, then develops primary and secondary circular reactions, advances to coordinating secondary actions, and then engages in tertiary circular reactions where they vary actions to observe outcomes. This progression captures motor-based learning and problem-solving before symbolic thought emerges. Saying they include reflexes up to coordination of tertiary reactions correctly reflects the range of motor-driven changes within this stage.