Russell A. Barkley:

1. Self-Restraint (executive inhibition) – This represents self-stopping or the ability to interrupt the flow of ongoing behavior that serves initially to decouple a stimulus or event from the subsequent response to be prepared for it. It involves (a) the capacity to suppress or otherwise disrupt or prevent the execution of a prepotent or dominant response to an event (the response that has been previously associated with reinforcement or has the highest likelihood of being performed under ordinary circumstances); (b) the capacity to interrupt an ongoing sequence of behavior toward a goal if it is proving to be ineffective; and (c) the capacity to protect the self-directed actions that will subsequently occur and the goal-directed actions they are guiding from interference by external and internal goal-irrelevant events (creating a freedom from distraction or a control of interference).

2. Self-Directed Sensory-Motor Action: This is an alternative means of defining nonverbal working memory and refers chiefly to the use of self-directed visual imagery along with the private rehearsal of visuo-motor actions it permits. While this largely is comprised of visual imagery, or the mind's eye, it also consists of the other senses, such as private hearing to the self, re-tasting, re-smelling, and re-feeling (kinesthetic-proprioceptive experience) to the self. In totality, this EF provides for the conscious, willful re-experiencing of past events that provides a metaphorical Cartesian theater of the mind. Yet, this capacity also eventually comes to include sensory and motor actions to the self that permit an individual to privately practice or re-perform sensory-motor actions to one's self creating a form of mental behavioral simulation.

3. Self-Directed Private Speech: This EF is the alternative explanation for the verbal working memory system to that offered by information processing and traditional cognitive models of EF, such as Baddeley's phonological loop in his model of working memory (Baddeley, 1986; Baddeley & Hitch, 1994). It is based on Vygotsky's theory of the internalization of speech to form the mind's voice used in verbal thinking (see above). Individual's talk to their self to permit not just a private rehearsal of utterances (verbal simulations) but also to self-instruct, self-question, and other verbal means by which language can be used for self-regulation, self-organization, and problem-solving.

4. Self-Directed Emotion/Motivation: This EF is believed to arise from the combination of 1-3 above in which the individual comes to use inhibition, private imagery (and sensing more generally), and private speech to initially inhibit strong emotions and then to down-regulate or otherwise moderate them (Ochsner & Gross, 2005, 2008; Ochsner et al., 2009). They then employ these other EFs to replace the initial strong emotion with alternate emotional responses more consistent with social demands and the individual's goals and longer-term welfare. Because emotions are motivational states, this EF also provides for the capacity for self-motivation – the drive states needed to initiate and sustain action toward the future. Recent research in neuro-imaging and in developing rating scales of EF suggest that the emotion regulation and motivation regulation aspects of this unit may be partially separable both neuro-anatomically (Murray, 2007; Rushworth et al., 2007) and behaviorally (Barkley, 2010c).

5. Self-Directed Play (Reconstitution): This EF is an alternative to the planning, problem solving, and innovative (generativity/fluency) components noted in other views of EF. It is hypothesized to be founded on the development of play and pretense in childhood (Carruthers, 2002) and is seen as essentially a two-step activity. The first is analysis, or taking apart features of the environment and one's own prior behavior toward it. This is followed by synthesis or the recombination of components of the environment and behavioral structures into novel combinations. These novel combinations can then be tested out against a criterion, such as a problem or goal, for their likely effectiveness in over-coming obstacles to goal attainment. While this begins as observable manual play, it progresses like the other EF components to being turned on the self and internalized as a form of private mental play. This permits both the manipulation of mentally represented information about the environment and about prior behavioral structures so as to yield new combinations that can serve as options for problem solving toward goals. It is possible that this component can be subdivided into both nonverbal and verbal modules that provide for fluency and generativity in each of these forms of behavior. Nonverbal, verbal, and action fluencies are believed to arise from this EF.

6. Self-Directed Attention – Self-Awareness: It has become increasingly clear since the foregoing original model of EF was first proposed that a sixth unit may be distinguished from these five. Originally, it was housed within the second module above dealing with self-directed sensory-motor actions, particularly imagery. Yet it is so important as the starting point for EF, has been acknowledged so in prior reviews of PFC functions as the pinnacle EF or central executive, and may arise out of more than just self-directed sensing as to probably warrant being a distinct component of this model. This is the self-direction of attention that comes to create self-awareness. Though listed here as the last component of the model for explication's sake, it likely is the first to arise in development and may well be the most important; out of this module arises self-consciousness or self-awareness that must be seen as a precursor to all other forms of self-regulation set forth above. It is here that the individual becomes conscious or aware of the entirety of their internal and external states, drives, wants, and actions and so achieves an organized, integrated unity or sense of self. As noted previously, this is the prime candidate to be the central executive.