Table 1.

Summary of the theoretical models concerning cognitive-control abilities.

The “unity and diversity” model [22]	Three cognitive-control abilities engaged in complex executive tasks: (a)shifting between tasks or mental sets (b)updating and monitoring of working-memory representations (c)inhibition of dominant or prepotent responses The abilities are separable but moderately correlated, indicating both unity and diversity of executive functions.
The “load theory” [23]	Cognitive control & perceptual load are associated with selective attention. Two mechanisms are activated against distractor intrusions: (a)a perceptual-selection mechanism that reduces distractor perception in situations of high perceptual load (b)a cognitive-control mechanism that acts to ensure that attention is allocated in accordance with current stimulus-processing priorities and minimizes intrusions of irrelevant distractors as long as working memory is available to actively maintain the current priority set
The “two-factor” theory of cognitive control [24]	Tests of working memory (WM) and fluid intelligence are related. WM reflects the ability to control attention, particularly when other elements of the internal and external environment could capture attention away from the currently relevant test. Individual differences in WM capacity lead to performance differences. WM or executive attention is important for maintaining information in active memory and secondly, is important in the resolution of conflict resulting from competition between task-appropriate responses and prepotent but inappropriate responses.
The “unity and diversity” model of executive functions in a behavioral and a genetic level [25]	At a behavioral level Executive functions (EFs) share common functions but have large differences between patients and inpatients. EF tests show low correlations due to task impurity; therefore, multiple measures are necessary. Inhibition, updating, and shifting are combined in the service of more complex EFs such as planning. EFs can be broken down into more basic functions. EFs are not the same as intelligence. Some EF components differentially relate to intelligence.