Questions: Working Memory and Executive Control Development

Question 1

A 9-year-old consistently loses track of multi-step math problems when a peer talks nearby, even though she understands each step individually. According to the developmental model, which capacity most directly explains this difficulty?

• A. Long-term memory — she has not stored enough procedural knowledge
• B. Working memory — limited capacity to hold and manipulate information under divided attention
• C. IQ — her general intelligence predicts performance on all academic tasks equally
• D. Inhibitory control — she cannot suppress her interest in her peer's conversation

Answer: (B)

Working memory is the cognitive workspace for holding and manipulating information in real time. Multi-step tasks are exactly where its limits bite: each step must be held active while the next is processed, and distraction degrades this maintenance. This is distinct from long-term memory (she understands the steps) and from IQ (working memory is predictive of academic success independently of IQ). Inhibitory control is relevant too, but the primary bottleneck described is maintaining information across steps, which is a working memory function.

Question 2

The A-not-B error, in which an infant reaches for an object in its old hiding location after watching it be moved, is a classic demonstration of which developing capacity?

• A. Working memory updating — the infant cannot refresh the contents of the workspace to reflect new information
• B. Cognitive flexibility — the infant cannot shift from one rule to another
• C. Inhibitory control — the infant cannot suppress the prepotent reach response toward the original location
• D. Language — the infant cannot process the verbal instruction to look elsewhere

Answer: (C)

The A-not-B error is specifically a failure of inhibitory control: the infant has a habitual, prepotent reach toward location A and cannot suppress it in favor of the new correct location B. This is the canonical demonstration of immature inhibitory control in early development. Working memory updating (option A) and cognitive flexibility (option B) are also executive functions, but the defining feature of the A-not-B scenario is suppressing a learned motor habit — inhibition.

Question 3

Working memory is the brain system responsible for the permanent storage of facts and autobiographical memories for later retrieval.

• T. True
• F. False

Answer: False

Working memory is a short-term, capacity-limited workspace for holding and manipulating information that is currently active — not a long-term storage system. It is contrasted with long-term memory, which stores knowledge persistently. Working memory holds a phone number while you dial it; long-term memory is what lets you remember a phone number you learned years ago. The capacity limit of working memory (roughly 3–4 items in young children, approaching 7±2 in adults) reflects its role as an active processing space, not a storage archive.

Question 4

Inhibitory control and cognitive flexibility are dissociable executive functions that develop at different rates and can be selectively impaired.

• T. True
• F. False

Answer: True

The three core executive functions — inhibitory control, working memory updating, and cognitive flexibility — are related but distinct. Inhibitory control develops earliest in childhood; cognitive flexibility matures later and remains sensitive to context into adolescence. They show different patterns of individual variation and can dissociate in neuropsychological profiles: a child may have strong inhibitory control but poor cognitive flexibility, or vice versa. ADHD, for instance, is associated with specific inhibitory control deficits, while some learning profiles show working memory weaknesses without proportionate inhibition impairments.

Question 5

Why does the late maturation of the prefrontal cortex specifically predict the behavioral profile of adolescence — particularly the gap between emotional reactivity and cognitive control?

Model answer: Emotional reactivity is driven largely by limbic structures (amygdala, reward circuitry) that mature early. Cognitive control — the ability to override impulses, plan, and regulate behavior — depends on the prefrontal cortex, which continues myelinating and pruning synapses into the mid-20s. Because PFC maturation lags limbic maturation by years, adolescents have strong emotional reactions but immature brakes. This imbalance — not immaturity across the board — explains why adolescents can be sophisticated reasoners yet still make impulsive decisions under emotional or social pressure. The maturational gap is structural, not merely motivational.