All 4 Terms & Definitions
- Competing frameworks: Miyake vs Diamond
- There is no universally agreed taxonomy of executive functions. Miyake et al. (2000) used latent variable analysis to identify three separable but correlated factors: inhibition (suppressing prepotent responses), updating (monitoring and refreshing working-memory contents), and shifting (switching between mental sets). Diamond (2013) proposed inhibitory control, working memory, and cognitive flexibility as three core EFs, with higher-order functions — planning, reasoning, problem-solving — built from these. The terminologies overlap: updating is a working-memory operation; shifting corresponds closely to cognitive flexibility. Both frameworks agree that executive functions are distinguishable but correlated.
- Executive-control networks
- Executive functions are supported by distributed brain networks rather than the prefrontal cortex alone. Key systems include the fronto-parietal control network (lateral PFC + posterior parietal cortex), which maintains task rules and working-memory contents; the cingulo-opercular network (anterior cingulate cortex + anterior insula), which sustains task engagement; and the basal ganglia, which contribute to action selection and inhibitory control. The dorsolateral PFC is associated with working memory and planning; the orbitofrontal cortex with impulse control and decision-making under uncertainty. Damage to any part of this system can produce executive deficits.
- Measuring executive functions
- Executive functions are assessed with tasks designed to tax specific processes — but no single task measures one process in isolation. The Stroop and go/no-go tasks target inhibitory control but also involve attention and processing speed. The WCST and task-switching paradigms target flexibility but require working memory. N-back and operation-span tasks measure updating. This task impurity problem means poor performance on one test should not be interpreted as a direct readout of a specific executive deficit. Performance also varies with motivation, fatigue, and stress.
- Higher-order executive functions
- Planning, reasoning, problem-solving, decision-making, and performance monitoring are sometimes described as higher-order executive functions, built from the three core processes. Planning requires working memory (holding the goal state), inhibitory control (suppressing premature actions), and flexibility (considering alternative steps). Standardised tests such as the Tower of London and Tower of Hanoi measure planning; the Iowa Gambling Task measures decision-making under uncertainty. These functions are particularly vulnerable to frontal-lobe damage and to the executive difficulties seen in ADHD and ageing.