Review of Executive Functions: What They Are, How They Work, and Why They Evolved, by Russell A. Barkley

Abstract

[Author Affiliation]Joseph C. Blader. Department of Psychiatry, Division of Child and Adolescent Psychiatry, University of Texas Health Science Center at San Antonio, San Antonio, Texas.ISBN 978-1-4625-0535-7. 2012. New York: Guilford Press. 244 pp.Address correspondence to: Joseph C. Blader, PhD, University of Texas Health Science Center at San Antonio, Department of Psychiatry, Division of Child and Adolescent Psychiatry, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, E-mail: blader@uthscsa.eduLeave it to Russell Barkley, one of our field's most expansive and nimble thinkers, to combine at least two books into this volume of just over 200 pages of text.The first offers a conceptualization of executive functions (EF) intended to remedy flaws in prevailing ideas about them, which Barkley identifies in a withering critique. The idea he elaborates is that EF are self-directed actions needed to choose and to create, enact, and sustain actions toward those goals (p. 60). Notice the verbs in this definition - for example, choose, create - because they signify Barkley's real passion, reclaiming, on behalf of the living, socially engaged, striving self, territory in psychology now occupied by pallid, eviscerated entities such as the central executive. Barkley's criticism of the EF field dutifully includes concerns about the psychometric properties of current measures, the tendency to confuse anatomical localization with a meaningful definition (e.g., EFs are what the frontal lobes do), and weak consensus on core concepts. But he saves his most vehement language to attack the reductionism of the individual to, in essence, software: Instead, cognitive neuropsychology's view of humanity is frankly not worth having - an Orwellian automaton of an information processor without a sense of self.Barkley goes on to enumerate eight fundamental capacities upon which EF, as he defines them, develop. Spatial, temporal, motivational, inhibitory, conceptual/abstract, behavioral-structural, social, and cultural capacities all get their moments in the spotlight. Although not exactly pulled out of thin air, the framework is chiefly heuristic and derived, unapologetically, more from reason than evidence of how the brain might actually work. However, Barkley offers at least one intriguing, and, I think, elegantly argued, idea: That beneath it all lie the capacities for vicarious learning and contemplation to anticipate and manage situations that one has not personally encountered, which are, perhaps, the game changers in human evolution. But all this is a prelude to the next Great List that occupies nearly half the book, a hierarchy of human functions and activities that EF enable, and an analysis of how their effects on the social and physical environments boomerang back to shaping the individual's behavioral repertoire.These ripple effects of human activities that EF enable give rise to the second theme, which could easily have spawned a separate book. Barkley argues that these extended effects are the why of EF. To explain the evolution of EF, Barkley turns to the extended phenotype concept developed by Dawkins (Dawkins 1999). The kernel of the extended phenotype idea is that the effects of a genotype extend beyond the organism that houses it. When such distal effects of a particular allele help to propagate it in succeeding generations (i.e., natural selection favors it), these effects are as much part of the gene's phenotype as, for example, hair color. Dawkins realizes that at first glance this is an unusual way to think about gene effects, and eases us into the idea by pointing out that the proximal effect of any coding gene is simply to synthesize a protein. How that protein, in tandem with other parts of the genome, gives rise to any characteristic of the organism, is already an enormous way down the road from that initial biochemical consequence. We could readily accept that web construction is a rather direct consequence of a spider's genome. …