Executive Functions of the Frontal Lobes: A New Perspective on an Old Story
On September 13, 1848, an apparently responsible, capable, and virile 25-year-old foreman of a railroad construction crew, named Phineas Gage, accidentally dropped a 131/4-pound iron tamping rod on a dynamite charge. The resulting explosion drove the rod through the left side of his face and out the top of the frontal portion of his cranium.
Seventy-four days after the accident, Phineas was able to return to his home 30 miles away. But there were discernible differences in Phineas’s behavior, not related to his health, general intelligence, or memory.
Physician J. M. Harlow (1868) was Phineas’s attending physician. Harlow wrote about the changes in behavior that happened after the patient’s accident. Clearly, Harlow was associating Phineas’s most important change to the loss of his once shrewd business acumen and his former ability in “executing all of his plans of operation.”
Harlow’s description may have been the first in the written psychological literature for the frontal lobe metaphor: that the frontal lobes serve as a kind of executive that makes decisions, forms goals, devises strategies for attaining these goals, plans, organizes, and changes and devises new strategies when initial plans fail.
Subsequently, this executive functions model has been developed by a scientific discipline known as neuropsychology. This field provides explanations for brain and behavior relationships based on studies of brain-damaged patients, clinical populations with suspected brain dysfunction, and healthy people.
Tests and measurements on the latter group (healthy people) help to define what normal or average functioning is so that behavior that deviates from standard functioning can be better defined. Neuropsychology is also broadly concerned with how the brain and its parts function and in identifying the symptoms of dysfunction.
One of the most prominent neuropsychologists of modern times was Russian Alexander Luria (1966), who wrote extensively about these executive functions of the frontal lobes.
Luria noted that patients with frontal lobe damage frequently had their speech, motor abilities, and sensations intact, yet their complex psychological activities were tremendously impaired. He observed that they were often unable to carry out complex, purposive, and goal-directed actions. Furthermore, he found that they could not accurately evaluate the success or failure of their behaviors, especially in terms of using the information to change their future behavior. Luria found that these patients were unconcerned with their failures, and were hesitant, indecisive, and indifferent to the loss of their critical awareness of their own behaviors.
Lezak (1982), a contemporary American neuropsychologist, wrote that the executive functions of the frontal lobes were:
…the heart of all socially useful, personally enhancing, constructive, and creative abilities. Impairment or loss of these functions compromises a person’s capacity to maintain an independent, constructively self-serving, and socially productive life no matter how well he can see and hear, walk and talk, and perform tests. (p. 281)
Welsh and Pennington (1988) defined executive functions in a neuropsychological perspective as the ability to maintain an appropriate problem-solving set for the attainment of a future goal. Pennington and Ozonoff (1996) view the domain of executive functions as distinct from cognitive domains such as sensation, perception, language, working memory, and long-term memory. Also, they see it as overlapping with such domains as attention, reasoning, and problem-solving “but not perfectly.” (p. 54). They also add interference control, inhibition, and integration across space and time as other aspects of executive function.
Their central view of executive function is a: context-specific action selection, especially in the face of strongly competing, but context-inappropriate, responses. Another central idea is maximal constraint satisfaction in action selection, which requires the integration of constraints from a variety of other domains, such as perception, memory, affect, and motivation. Hence, much complex behavior requires executive function, especially much human social behavior. (p. 54)
So, this seems to be how the idea of the executive functions of the frontal lobes originated. In the next post, we’ll detail exactly what these functions are supposed to be as they were laid out earlier this century.