Thursday, April 17, 2008

Executive functions and intellectual performance

I just read an excellent overview of the literature re: the construct of executive functions (EF). The article (by Ardila) is "in press" in Brain and Cognition (an excellent journal). Although I was not personally interested in the later portion of the articles discussion of the evolutionary basis of executive functions, I found everything prior to that section excellent.

The article provides a nice synthesis of the status of the theoretical and empirical research re: the construct of EF. What continues to excite me is the strong link between the prefrontal cortex (the dorsolateral prefrontal lobes in particular) and EF. My reading of the literature, which I've summarized in two of my PPT slide shows (in particular, see "Brain Clock IM 2007 Keynote" under the On-line PPT Slide section of the right side of this blogs home page), suggests a strong link between temporal processing/mental time-keeping (the IQ Brain Clock) and the dorsolateral prefrtonal cortex. This article is consistent with this finding.

The article also serves to remind those of us who are primarily focused on intelligence/cognitive constructs that EF is involved in two broad human behavior systems. One deals more with cognitive functions and the other more motivational/emotional/affective behaviors. I often tend to forget about the later....and I shouldn't, given that these other functions are related to the self-regulatory learning strategies conative domain I have described in a Model of Achievement Competence and Motivation (MACMM).

Article abstract
  • In this paper it is proposed that the prefrontal lobe participates in two closely related but different executive function abilities: (1) ‘‘metacognitive executive functions”: problem solving, planning, concept formation, strategy development and implementation, controlling attention, working memory, and the like; that is, executive functions as they are usually understood in contemporary neuroscience; and (2) ‘‘emotional/ motivational executive functions”: coordinating cognition and emotion/motivation (that is, fulfilling biological needs according to some existing conditions). The first one depends on the dorsolateral prefrontal areas, whereas the second one is associated with orbitofrontal and medial frontal areas. Current tests of executive functions basically tap the first ability (metacognitive). Solving everyday problems (functional application of executive functions), however, mostly requires the second ability (emotional/ motivational); therefore, these tests have limited ecological validity. Contrary to the traditional points of view, recent evidence suggests that the human prefrontal lobe is similar to other primates and hominids. Other primates and hominids may possess the second (emotional executive functions) prefrontal ability,-but not the first (metacognitive executive functions) one. It is argued that metacognitive executive functionsare significantly dependent on culture and cultural instruments. They probably are the result of the development and evolution of some ‘‘conceptualization instruments”; language (and written language as an extension of oral language) may represent the most important one. The second executive function ability (emotional/motivational) probably is the result of a biological evolution shared by other primates.

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1 comment:

gweipo said...

I'm interested in what you're saying, and would love to know what your opinion is on the popular research of people like Sax (why Gender matters) on the wiring of male vs. female brains....
as a mother of a son and a daughter I am profoundly struck by the differences.
Funnily enough this afternoon my son spontaneously started clapping the rhythm of a song he'd heard yesterday in his violin class. Which led me to re-read what you've written.

Is it cause or effect. i.e. can intelligence be trained by training the ability to keep the rhythm, or vice versa?