By the end of the ______ period, children first become capable of engaging in…

Concept

Piaget described cognitive development as a sequence of stages, each organized around a different way of representing and reasoning about experience.

A mental representation is an internal symbol for an absent object or event. Its emergence permits deferred imitation and the earliest forms of pretend play.

Application

The blank asks for the stage by whose end this representational capacity has emerged. In Piaget’s final sensorimotor substage, around 18–24 months, children can use internal symbols rather than relying only on immediate sensory action.

Contrast

• Pre-operational (about 2–7 years): symbolic thought and pretend play become frequent and elaborate after their initial emergence.

• Concrete operational (about 7–11 years): children apply logical operations to concrete situations, including conservation and classification.

• Formal operational (about 11 years onward): abstract, hypothetical, and deductive reasoning becomes possible.

• Sensorimotor (birth to about 2 years): knowledge begins through sensory and motor action, and internal representation emerges in the final substage.

Result

Therefore, the period completed when representational mental activity first becomes possible is the sensory–motor period.