It’s appropriate that Robert Kurzban author this overview of evolutionary psychology, as he is the academic offspring of Leda Cosmides and John Tooby who are considered the founders of evolutionary psychology (EP). Needless to say, Kurzban is an active and productive evolutionary psychologist.
Kurzban’s overview of EP is excellent, outlining EP’s principles of functionality, adaptationism, and modularity. My remarks, outlined below, are offered to flesh out some of the ideas presented by Kurzban.
In the Plausible Evolved Functions section, the concept of an “adaptive problem” is introduced, but not fully articulated. An adaptive problem is an obstacle or impediment that was recurrent during a species’ evolutionary history and whose solution affected the survival and reproduction (i.e., genetic propagation) of an organism. Adaptive problems are not necessarily “problems” in the negative sense; instead, they are the “regularities of the physical, chemical, developmental, ecological, demographic, social, and informational environments encountered by ancestral populations during the course of a species’ or population’s evolution” (Tooby & Cosmides, 1992, p. 62). Recognizing others’ faces was one adaptive problem our ancestors faced. This adaptive problem lead to the evolution of cognitive architecture associated with face recognition.
In the last paragraph in the Plausible Evolved Functions section, Kurzban discusses the concept of evolutionary time lags. Including the common example of maladaptive modern eating habits might help to bring home this point. Our preferences for sugar and fat were once adaptive because of the scarcity of food items rich in these elements in our evolutionary past but now generate unhealthy food consumption, given the wide availability of these elements in the modern environment. Would you like fries with that? You bet I would.
In the Levels of Explanation section, three levels of explanation are discussed. One is the functional level, one might be the mechanistic (or proximate) level, but it’s not clear what the other level is. Perhaps the last sentence could be modified (and completed) to read, “…it is convenient to break down explanations for biological phenomena into three levels: _____, _____, and _____.”
In the Methods section, one statement might be added to the first paragraph. It might be worth noting that claims of adaptations typically are stated as tentative until the hypothesized adaptation has undergone rigorous hypothesis testing using multiple methods and techniques.
In the Panadaptation section, it might be a good idea to note that identifying byproducts is as rigorous a process as identifying adaptations because the hypothesis that a trait is a byproduct requires the identification of the adaptation of which it is a byproduct.
-Aaron Goetz, Ph.D.
Robert Kurzban’s article provides an excellent overview of evolutionary psychology. My comments, therefore, suggest only minor additions/revisions. Kurzban states that the source of functional complexity is evolution by natural selection. It may be worth mentioning sexual selection here too. This would also suggest citing Darwin, (1871) in the opening paragraph. A brief note that these two selection forces operate in opposition to one another might also be included (e.g., Zahavi, 1975).
Kurzban states that the notion that the source of functional complexity is evolution by natural selection is “uncontroversial.” Several authors, however, have challenged this claim by noting other sources (e.g., Gould, 1997; Lickliter & Honeycutt, 2003)).
Along with the important developments to Darwin (1859) listed, Kurzban might also mention Trivers (1971,1972, 1974).
Kurzban notes, “A commonly-used analogy is that organs can similarly be analyzed as functional components of the whole organism, and organs can themselves be further broken down into functional subcomponents.” Although this is, of course, correct, I am unsure as to whether the analogy aids the reader unfamiliar with evolutionary psychology. This is because noting that organs can themselves be broken down into functional subcomponents might confuse the notion of the integrity of functional subcomponents of organisms. Personally, I think the analogy between bodily and mental organs might be more helpful for the naïve reader.
In the fourth paragraph, Kurzban notes, “Although there is significant disagreement within the discipline.” It is not, however, quite clear here as to what this disagreement pertains. Is it over whether the mind consists of subcomponents or the number of them? Also some references might help.
In the fifth paragraph, Kurzban writes, “The reasoning behind this position rests not on the analogy with organ systems.” I may be wrong but although, as Kurzban notes, the cognitive revolution’s idea regarding the logic of computation was a primary force underlying this reasoning, did not Chomsky make the analogy with bodily organs and was it not this that kick started the cognition revolution? Thus, maybe “solely” might be inserted into the above sentence.
Also in paragraph five, Kurzban writes the broader the range of problems a mechanism is designed to solve, the worse it will be at solving them, and, the more narrow the range of problems a computational mechanism is designed to solve, the better it will be at solving them. I would prefer one or the other, not both, of these statements. In paragraph nine, Kurzban notes, “A common term in evolutionary psychology is ‘’modularity.’’ It might be worth noting that this term does not originate in EP and referencing Fodor (1983) here.
In paragraph ten, Kurzban notes, “Adaptive problems are diverse, and depend exquisitely on the life history of the species in question. That is, because different organisms survive and reproduce in very different ways, the features – and thus the genes – that are advantageous vary from one species to the next.” Many adaptive problems are similar across species, however, and that is why different species share many of their genes. In paragraph twelve, Kurzban notes, “the computational mechanisms humans possess are the ones generated by genes selected over the course of human evolutionary history.” There is no reference for this quotation.
Also in paragraph twelve, Kurzban writes, “Because of the way that brains, and especially development, work, humans can do many things for which there was not specifically selection in the past.” It may be worth stating that evolutionary novel tasks are performed through the use of abilities or amalgamations of abilities that have been selected for i.e. by directing abilities that have been selected for toward novel goals.
In paragraph sixteen, Kurzban writes, “One of the most thoroughly described phenomena in psychology to be described is the eye.” It might be better to replace “eye” with “vision.” The last sentence of the first paragraph in the section “Development”, namely “Natural selection therefore can be thought of as a process that retains genes that interact with the environment – i.e., cause development – in a way that leads to the reliable development of functional elements of the phenotype” repeats the first sentence of the paragraph. I would, therefore, suggest rewriting this paragraph.
In the final paragraph in the section “Development”, it might be worth having a final sentence stating something like, “As such, evolutionary psychology rejects the notion of ‘genetic determinism’.” Alternatively, the section, “Genetic Determinism” might be incorporated into the section on development.
In the final paragraph in the section “Panadaptationism”, that a trait is a byproduct generally requires an account of the adaptation or adaptations of which the trait in question is a byproduct.” Here, I suggest referencing Buss, Haselton, Shackelford, Bleske, & Wakefield (2002).
To support the position in the section, “Universality & Culture”, it might be worth quoting Tooby and Cosmides (1989): “The mapping between the innate and the manifest operates according to principles of expression that are specified in innate psychological mechanisms; these expressions can differ between individuals when different environmental inputs are operated on by the same procedures to produce different manifest outputs” (p. 36).
- Buss, D.M., Haselton, M.G., Shackelford, T.K., Bleske, A.L., & Wakefield, J.C. (2002). Adaptations, exaptations, and spandrels. In D. Levitin (Ed.), Foundations of cognitive psychology: core readings. Cambridge, MA: MIT Press [reprinted from American Psychologist, 53, 533-548.]
- Chomsky, N. (1957). Syntactic Structure. Mouton: The Hague.
- Darwin, C. (1871). The Descent of Man and Selection in Relation to Sex. London: Murray.
- Fodor, J. A. (1983). Modularity of mind: An essay on faculty psychology. Cambridge,
Mass.: MIT Press.
- Gould S. J., 1997. Evolution: The Pleasures of Pluralism. New York Review of Books, June 26, pp. 47-52.
- Lickliter, R., & Honeycutt, H. (2003). Developmental dynamics: Toward a
biologically plausible evolutionary psychology. Psychological Bulletin, 129, 819–835.
- Tooby, J. & Cosmides, L. (1989). The innate versus the manifest: How universal does universal have to be? Behavioral and Brain Sciences, 12, 36-37.
Trivers, R. L. (1971). The evolution of reciprocal altruism. Quarterly Review of Biology, 46, 35-57.
- Trivers, R. L. (1972). Parental investment and sexual selection. In B. Campbell, ed. Sexual Selection and the Descent of Man, 1871-1971, Aldine-Atherton, Chicago, pp. 136-179.
- Trivers, R. L. (1974). Parent-offspring conflict. American Zoologist, 14, 247-262.
- Zahavi, A. (1975). Mate selection – A selection for a handicap. Journal of
Theoretical Biology, 53, 205-214.
Alastair P. C. Davies, MA