I just finished reading a study titled The Persistence of Thought which examined the relationship between a working memory (WM) and inattention, specifically the maintenance of task-unrelated thinking (TUT). The subjects of the study were given a standard test for working memory and performed a series of undemanding computer simulated tasks. People with higher WM scores reported more episodes of mind wandering in TUT. The study reported: “We found that individuals with higher WM capacity reported more TUT in undemanding tasks, which suggests that WM enables the maintenance of mind wandering.”
While correlation does not prove causation, I am left wondering whether increasing the working memory of individuals results in an increase of mind wandering. This would seem to be the case. Likewise, what role does task difficulty play? The article begins by saying that “tasks that tax WM have consistently been found to decrease mind wandering.” The study revealed that individual’s with greater working memory reported the task to be easier. Does increasing the task difficulty improve performance?
Past research has consistently revealed a strong link between working memory and intelligence.
I am curious how this relates to the phenomenon of ADHD, the protypical example of a wandering mind.
In the past cognitive testing attributed a deficient working memory with ADHD symptoms, leading them to believe that a poor working memory was the cause of distraction. Researchers have identified neurochemicals, specifically dopamine and norepinephrine, as a key feature of understanding ADHD symptoms, and that with the supplementation of dopamine enhancing drugs working memory improves and attention returns.
Perhaps the indication of reward dictates improved performance on attention-related tasks? Perhaps a greater challenge poses a greater reward, and thus better performance?
Is school too easy for individuals with ADHD? Too unstimulating and unchallenging? Is the environment of formal education unsuited for ADHD learning?
Research has found neural hyperactivity is associated with individuals diagnosed with ADHD, as well as a host of other mental disorders that have been historically attributed to creative genius. (See Neurology of ADHD; Is there evidence for neural compensation in attention deficit hyperactivity disorder?; Is attention deficit hyperactivity disorder a valid diagnosis in the presence of high IQ?)
Along these lines, I found this study particularly interesting: “Task-related changes in cerebral blood flow (rCBF) in the men without ADHD were more prominent in the frontal and temporal regions, but rCBF changes in men with ADHD were more widespread and primarily located in the occipital regions.” Researchers observed diffused cCBF in individuals with ADHD, rather than accute rCBF in those without.
The results showed that: “Men without ADHD demonstrated significant time-related rCBF increases in the anterior cingulate and medial frontal regions (Brodmann area 32/10) and decreases in the left middle frontal regions (Brodmann area 9). Men with ADHD showed significant time-related decreases in the left middle (Brodmann area 21) temporal lobe and increases in the right lenticulate, left parahippocampal gyrus (Brodmann area 35/36), and bilateral cerebellum.”
The anterior cingulate: It appears to play a role in a wide variety of autonomic functions, such as regulating blood pressure and heart rate, as well as rational cognitive functions, such as reward anticipation, decision-making, empathy and emotion.
The medial frontal regions (Brodmann area 32/10): Dorsal region of anterior cingulate gyrus (Brodmann area 32) is associated with rational thought processes, most notably active during the Stroop task. Rostral prefrontal cortex (approximating Brodmann area 10) has been shown repeatedly to have a role in the maintenance and realization of delayed intentions that are triggered by event cues (i.e., event-based prospective memory).
The left middle (Brodmann area 21) temporal lobe: a region believed to play a part in auditory processing and language
The right lenticulate (See Data)
The left parahippocampal gyrus (Brodmann area 35/36): The perirhinal cortex (Brodmann area 35/36) receives highly-processed sensory information from all sensory regions, and is generally accepted to be an important region for memory. The perirhinal cortex is involved in both visual perception and memory; it facilitates the recognition and identification of environmental stimuli. Lesions to the perirhinal cortex in both monkeys and rats lead to the impairment of visual recognition memory, disrupting stimulus-stimulus associations and object-recognition abilities. The perirhinal cortex’s role in the formation and retrieval of stimulus-stimulus associations (and in virtue of its unique anatomical position in the medial temporal lobe) suggest that it is part of a larger semantic system that is crucial for endowing objects with meaning.
The bilateral cerebellum: the basic function of the cerebellum is not to initiate movements, or to decide which movements to execute, but rather to calibrate the detailed form of a movement.
What are the implications?
On another unrelated note, I found this study, titled Structural brain variation and general intelligence, very interesting as well. The “results underscore the distributed neural basis of intelligence and suggest a developmental course for volume–IQ relationships in adulthood.” As in, nurture over nature.
I’ve touched on these ideas many times before, specifically: Neural Hyperactivity: Genius and Deviant Psychology and Thoughts: Novelty, Education, Society, Theory