Dr. Barkley’s theories suggest that ADHD is a disorder not only of attention, but of executive functioning as well. Executive functioning describes a set of cognitive abilities involved in controlling and regulating other abilities and behaviors. Such functions are necessary in initiating goal-directed behavior, suppressing impulses arising from lower brain centers, and planning future behavior.
There are five key executive functions: Behavioral inhibition (critical to development of the other functions), non-verbal working memory, verbal working memory, emotional self-regulation and reconstitution. We’ll describe in more detail the consequences of delays in the development of these functions.
Behavioral inhibition involves the ability to delay one’s response to an event (allowing time to think), interrupt a chain of responses to an event and the capacity to keep competing events from interfering with the initial response. Without this ability a person would be entirely focused on the immediate consequences of any action or behavior and would be unable to develop the capacity for self-control. Kids in whom the development of this capacity is delayed will be unable to suppress the publicly observable aspects of behavior.
Non-verbal working memory involves the capacity to maintain a picture of events in one’s mind. The ability to analyze situations for recurring patterns in order to predict future events is critical in anticipating consequences of behavior, managing relationships and planning complex, goal-directed behavior. Moral conduct and social cooperation are contingent upon this capacity as well the retention of events in sequence that allows one to estimate the time required to perform a task. Kids who experience delays in developing this capacity will have more difficulty remembering multi-step directions, more difficulty completing tasks (especially tasks that take a long time to complete), and will tend to underestimate the amount of time necessary to complete assigned tasks.
Verbal working memory involves the capacity to think in words. Internalization of speech allows kids to internalize social norms and rules, facilitating moral development. As kids develop this capacity, they’re able to hold a thought in their mind without having to actually say what they’re thinking. A classic example is the inability of little kids to pray silently.Kids with delays in development of verbal working memory would tend to talk excessively compared to peers, have more difficulty organizing and communicating thoughts, struggle more with use of proper grammar and experience more challenges in following rules and directions.