Cognitive Development in Toddlerhood

All 6 Terms & Definitions

Symbolic function (Piaget)

The capacity to use one thing to represent another — a word, image, gesture, or object standing for an absent referent. Emerges around 18–24 months at the end of the sensorimotor period. Underlies language, pretend play, deferred imitation, and mental imagery. For Piaget, symbolic function is the defining achievement that marks the transition from sensorimotor to preoperational thought.

Pretend play

The use of objects, actions, or roles in non-literal, "as if" ways — feeding a stuffed animal, using a block as a car. Emerges around 12–18 months, initially with self-directed actions, then extended to others and to substitute objects. Tracks broader symbolic development and is considered a reliable index of representational capacity in toddlerhood.

Language and thought (Vygotsky)

Vygotsky argued that language and thinking have separate developmental origins (the pre-linguistic stage of thought; the pre-intellectual stage of language) but merge around age 2, transforming both. From this point, thought becomes verbal and language becomes rational — a qualitative leap that enables increasingly sophisticated self-regulation and problem-solving.

Inhibitory control

The ability to suppress a dominant or prepotent response in favour of a goal-appropriate one. In toddlerhood, measured via A-not-B tasks and the Detour Reaching task. Extremely limited at 12 months, it develops substantially across toddlerhood and early childhood, driven by prefrontal cortex maturation. Foundational to later executive function, emotion regulation, and academic readiness.

Working memory (early development)

The capacity to hold and manipulate information in mind over short periods. In toddlerhood, working memory is extremely limited — typically one to two units — but expands substantially across the preschool years. Underlies object tracking, simple problem-solving, and early language comprehension. Prefrontal and parietal development drives its expansion.

Causal understanding

Toddlers develop an understanding that events have causes, distinct from mere association. By 24 months, toddlers show a preference for causal over coincidental sequences; they can use a tool to retrieve an out-of-reach object (demonstrating means-ends reasoning), and they infer hidden causes from incomplete evidence. This emerging causal framework is foundational for later scientific reasoning.