I am very enthusiastic about Bjorklund & Pellegrini’s 2002 text, Evolutionary Developmental Psychology. I am going to discuss four places I believe that the book’s discussion can be extended, on ADD, domain generality, geological time, and group selection. While I feel the authors’ work to be incomplete in these areas, I choose these areas because otherwise the book seems flawless.
On page 5, the authors mention mention that “natural selection has similarly shaped domain-general information processing mechanisms,” and that “working memory” and “speed of processing” are examples of such domain-general mechanisms. I agree that these things exist, are important, and were shaped through evolution, though I do not know if they are “domain general.”
For instance, I think it is clear that working memory effects how we memorize names, how we do long division, and how we solve complicated puzzles. But does working memory capacity load only cheater detection, or in the hundred subconscious ques we receive to tell us how the person we talk to is feeling? I believe the authors could have been more accurate had they spoken of these “conscious, domain-multiple” skills instead of domain-general ones.
Additionally, I think the author’s words on the nature of selection cover much of evolution. They write that “natural selection does not necessarily yield what is ‘best for the group’ but rather works on the level of the individual” (14). Sometimes this is true. However, eusocioal adaptations (those that benefit the group but harm an individuals’ inclusive fitness) have been observed in the wild (Wilson & Holldobler, 2005) and computer simulations (Hammond & Axelrod, 2006) and network analysis (Bloom, 2000) imply that something similar may exist among men . Selection pressure is not limited to the individual level, or the genetic level, or the group level, but exists on every level of organization (Alford & Hibbing, 2004).
Relatedly, the authors claim that “individuals who truly have ADHD would be at a disadvantage in any environments” (28). This may or may not be true, but the Goldstein & Barkley (1998) paper they say they agree with goes further, arguing that ADHD could not be “adaptive” (1) or “adapted” (2) (it is not clear that Goldstein & Barkley understand the difference in these concepts) because because it is not shown to be beneficial in some economic activity (hunting, wading, etc). Goldstein & Barkley then bizarrely state: “[Advocates for ADHD] can not on the one hand argue that ADHD needs to be taken seriously as a legitimate developmental disability. Then on the other hand simultaneously sing its praises as a once successful adaptation that leads to higher intelligence, greater creativity, and heightened sensory awareness, but that now results in suffering due to an overcontrolled, linear-focused, and intolerant culture” (4-5). Why this should be true is beyond me. It may well be that ADHD is adapted on a genetic level to increase reproduction. For instance, if ADHD leads to rape (Giotakos, Markianos, & Vaidakis, 2005) then it easily could be an adaptation that is beneficial to a selfish gene while being harmful to individuals and society. Alternatively, ADHD may well be a stable polymorphism, in other words humanity may be â€œa mixed population [that] is evolutionary stableâ€ (Buller, 2005, 42) with regard to ADHD. This could arrive if at certain times a group’s survival hinged on having hyperactive members, and at other times hinged on having members capable of concentration.
Last, while I agree that the “human mind has been prepared by natural selection, operating over geological time, for life in a human group” (Bjorklund & Pellegrini, 4). However, human minsd have also been prepared by natural selection, operating over historical time, for life in human groups (Voight, et al., 2006). That is, human genomes of different populations have undergone selection within the past few thousand years. Evolution acted in the past, giving us stone-age brains for our modern lives. But it also acted more recently, adapting those stone-age brains for live in agricultural communities.
However, while these are nit-picks, Bjoklund & Pellegrini’s contribution to the field should not be underrated. Their text competently integrates evolutionary psychology and cognitive psychology, two fields who share many assumptions but whose practitioners are often unaware of each other’s advances. It is through books like this can scientists in both domains leverage each other’s unique contributions and advance the state of our unified, scientific view of the world.
Alford, J. & Hibbing, J. (2004) .The Origin of Politics: An Evolutionary Theory of Political Behavior. Perspectives on Politics, 2(4), 707-723
Bloom, Howard. (2000). Global Brain. Wiley & Sons: New York, NY.
Bjorklund, D. F., & Pellegrini, A. D. (2002). The origins of human nature: Evolutionary developmental psychology. Washington, DC: American Psychological Association.
Buller, D.J. (2005). Adapting Minds. MIT Press: Cambridge, MA.
Goldstein, S., & Barkley, R. (1998). ADHD, hunting, and evolution: “just so” stories. The ADHD Report 6(5): 1-4.
Giotakos, O., Markianos, M., & Vaidakis, N. (2005). Aggression, impulsivity, and plasma sex hormone levels in a group of rapists, in relation to their history of childhood attention-deficit/hyperactivity disorder symptoms. Journal fo Forensic Psychiatry and Psychology 16(2): 423-433.
Hammond, R., & Axelrod, R. (2006) The Evolution of Ethnocentricism. Journal of Conflict Resolution, 50(6).
Spielman, R.S., Bastone, L.A., Burdick, J.T., Morley, M., Ewens, W.J., & Cheung, V.G. (2007). Common genetic variants account for differences in gene expression among ethnic groups. Nature doi:10.1038/ng1955.
Voight BF, Kudaravalli S, Wen X, Pritchard JK (2006) A Map of Recent Positive Selection in the Human Genome. PLoS Biol 4(3): e72 DOI: 10.1371/journal.pbio.0040072
Wilson, E. O., & Holldobler, B. (2005). Eusociality: Origin and Consequences. PNAS 102(38)-13367-13371.
Evolutionary Cognitivism, a tdaxp series
1. Selection and Cognition
2. Epigentics and Diversity
3. Children and Civilization
4. The Implicit and the Explicit
5. Man Among Men
6. More Than Genes