Executive system

The executive system is a theorised cognitive system in psychology that controls and manages other cognitive processes. It is thought to be involved in processes such as planning, cognitive flexibility, abstract thinking, rule acquisition, and inhibiting inappropriate actions and irrelevant sensory information.

It is also referred to as executive function or the central executive and plays a central role in many psychological theories.

Theories of the executive system were largely driven by observations of patients who had suffered frontal lobe damage. They exhibited disorganised actions and strategies for everyday tasks (a group of behaviours now known as dysexecutive syndrome) although they seemed to perform normally when clinical or lab based tests were used to assess more fundamental cognitive functions such as memory, learning, language and reasoning. It was hypothesised that, to explain this unusual behaviour, there must be an overarching system that co-ordinates other cognitive resources.

Psychologist Alan Baddeley had proposed a similar system as part of his model of working memory1 and argued that there must be a component (which he named the 'central executive') that allows information to be manipulated in short term memory (for example, when doing mental arithmetic).

However, the executive system has been traditionally quite hard to define, mainly due to what psychologist Paul Burgess calls a lack of "process-behaviour correspondence"2. That is, there is no single behaviour which can in itself be tied to executive function, or indeed executive dysfunction. For example, it is quite obvious what reading impaired patients cannot do, but it is not so obvious as to exactly what executive impaired patients might be incapable of.

This is largely due to the nature of the executive system itself. It is mainly concerned with the dynamic, 'online' co-ordination of cognitive resources and hence its effect can only be observed by measuring other cognitive processes. Similarly, it does not always fully engage except in real-world situations. As neurologist Antonio Damasio has reported, a patient (known by the initials EVR) with severe day-to-day executive problems may still pass paper-and-pencil or lab-based tests of executive function3.

The executive system is thought to be heavily involved in handling novel situations outside the domain of some of our 'automatic' psychological processes that could be explained by the reproduction of learnt schemas or set behaviours. Psychologists Don Norman and Tim Shallice have outlined five types of situation where routine activation of behaviour would not be sufficient for optimal performance4:
 * 1) Those that involve planning or decision making.
 * 2) Those that involve error correction or troubleshooting.
 * 3) Situations where responses are not well-learned or contain novel sequences of actions.
 * 4) Dangerous or technically difficult situations.
 * 5) Situations which require the overcoming of a strong habitual response or resisting temptation.