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Neuropsychology Review, Vol. 16, No. 1, March 2006 ( 2006) DOI: 10.1007/s11065-006-9002-x
Executive Function and the Frontal Lobes: A Meta-Analytic Review
Julie A. Alvarez1 and Eugene Emory2
Published online: 1 June 2006
Currently, there is debate among scholars regarding how to operationalize and measure executive functions. These functions generally are referred to as supervisory cognitive processes because they involve higher level organization and execution of complex thoughts and behavior. Although conceptualizations vary regarding what mental processes actually constitute the executive function construct, there has been a historical linkage of these higher-level processes with the frontal lobes. In fact, many investigators have used the term frontal functions synonymously with executive functions despite evidence that contradicts this synonymous usage. The current review provides a critical analysis of lesion and neuroimaging studies using three popular executive function measures (Wisconsin Card Sorting Test, Phonemic Verbal Fluency, and Stroop Color Word Interference Test) in order to examine the validity of the executive function construct in terms of its relation to activation and damage to the frontal lobes. Empirical lesion data are examined via meta-analysis procedures along with formula derivatives. Results reveal mixed evidence that does not support a one-to-one relationship between executive functions and frontal lobe activity. The paper concludes with a discussion of the implications of construing the validity of these neuropsychological tests in anatomical, rather than cognitive and behavioral, terms.
KEY WORDS: Executive function; Frontal lobe; Neuropsychology; Meta-analysis.
Executive functions generally refer to higher-level cognitive functions involved in the control and regulation of lower-level cognitive processes and goal-directed, future-oriented behavior. Over 2500 scientic articles have been published on this topic in the past 10 years. They have examined the role of executive functions in normal development (e.g., Espy and Kaufmann, 2002), Attention-Decit/Hyperactivity Disorder (e.g., Sergeant et al., 2002), Antisocial Personality Disorder (e.g., Morgan and Lilienfeld, 2000), Parkinsons disease (e.g., Dagher et al., 2001), and neuropsychiatric disorders including Schizophrenia and Obsessive-Compulsive Disorder (e.g., Nieuwenstein et al., 2001; Perry et al., 2001).
The component processes of executive functions have been investigated by means of factor-analytic studies. The Wisconsin Card Sorting Test (WCST) taps neu-
1Department of Psychology, Emory University, Atlanta, Georgia, 30322, USA.
2Center for Prenatal Assessment and Human Development, Emory University, Atlanta, Georgia, USA.
ropsychological processes involving (a) cognitive...