Barkley's Executive Functions Framework
According to Russell Barkley's model, executive functions consist of four core neuropsychological abilities that depend on behavioral inhibition: nonverbal working memory, internalization of speech (verbal working memory), self-regulation of affect/motivation/arousal, and reconstitution (analysis and synthesis of behavior). 1
The Four Executive Functions in Barkley's Model
1. Nonverbal Working Memory
- This function involves holding events in mind (retrospective function) and using this information to anticipate and prepare for upcoming events (prospective function) 1
- Enables individuals to mentally represent and manipulate visual-spatial information without external cues 1
- Critical for maintaining a sense of time and using past experiences to guide future behavior 1
2. Internalization of Speech (Verbal Working Memory)
- Represents the development of self-directed speech that becomes progressively more covert and internalized during childhood development 1
- Functions as verbal working memory, allowing individuals to use language to guide and control their own behavior 1
- Enables self-questioning, problem-solving through internal dialogue, and rule-governed behavior 1
3. Self-Regulation of Affect, Motivation, and Arousal
- This executive function controls emotional responses and motivational states to facilitate goal-directed behavior 1
- Allows individuals to modulate their emotional reactions to events rather than responding impulsively 1
- Enables the maintenance of drive and motivation toward long-term goals despite immediate frustrations 1
4. Reconstitution
- Involves two complementary processes: analysis (breaking down observed behaviors into component parts) and synthesis (recombining behavioral units into novel sequences) 1
- Permits behavioral flexibility and creativity by allowing individuals to generate multiple response options 1
- Essential for problem-solving and adapting behavior to novel situations 1
The Central Role of Behavioral Inhibition
Barkley's original 1997 model positioned behavioral inhibition as the foundational process necessary for these four executive functions to operate effectively 1, 2
- Behavioral inhibition includes three interrelated processes: inhibiting prepotent responses, stopping ongoing responses, and interference control (protecting the delay period from disruption) 1
- Without adequate behavioral inhibition, the four executive functions cannot be deployed effectively, leading to the characteristic symptoms of ADHD 1
Evolution of Barkley's Model
Barkley recently updated his model to elevate working memory from a mediator variable to a primary exogenous variable alongside behavioral inhibition, creating what is now called Barkley's Updated Executive Functioning Model (BUEFM) 2
- This change reflects the substantial independent role of working memory in explaining ADHD symptoms 2
- Research comparing the original model to the updated version shows that BUEFM demonstrates superior predictive power and better model fit indices (RMSEA of 0.067 vs 0.076 for the original model) 2
Clinical Implications
These executive functions collectively enable self-regulation by removing behavior from control by the immediate context and bringing it under the control of internally represented information and time 1
- The model explains ADHD as fundamentally a disorder of self-regulation rather than simply attention 1
- Individuals with ADHD demonstrate "blindness to time" - an inability to direct behavior toward the future and sustain goal-directed actions 1
- The framework predicts that ADHD returns control of behavior to "the temporal now," making individuals overly responsive to immediate environmental contingencies 1
Important Caveat
While Barkley's model specifically addresses ADHD pathophysiology, the broader field recognizes a simpler three-component framework of executive functions: inhibition (including response inhibition and interference control), working memory, and cognitive flexibility 3