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Is methodological adaptationism really so dangerous?In this paper, I defend against Lloyd’s criticism of methodological adaptationism. Methodological adaptationism is a research strategy widely used in evolutionary biology, in which “adaptation” is often used as a good organizing concept for evolutionary research (Godfrey-Smith 2001). Although great research progress has been made with the help of this strategy, there is still much criticism of methodological adaptationism as the “first choice” for evolutionary research (Gould and Lewontin 1979).
Lloyd (2015) discusses some dangers of methodological adaptationism from a new perspective called the “logic of research questions”, and proposes the “evolutionary factors framework” as an alternative approach. According to Lloyd, the research questions asked under methodological adaptationism and the evolutionary factors framework are logically different from each other. Since methodological adaptationists usually first assume the trait in question as an adaptation, their leading research question will be: “What is the function of this trait?” By contrast, researchers adopting the evolutionary factors framework will ask: “What evolutionary factors account for the form and distribution of this trait?” Lloyd argues that the methodological adaptationist research question excludes possible non-adaptive answers, brings about a lot of serious dangers, and hence is very harmful to evolutionary research.
I’m not going to say that methodological adaptationism is a perfect research strategy, but many of the problems proposed by Lloyd do miss the point: 1) Some of the dangers, such as shirking the “onerous burden of proof”, are not inherent to or brought about by methodological adaptationism per se. These dangers can be controlled or avoided, as long as methodological adaptationism is properly applied. 2) Some of the dangers, such as the lack of a stopping rule for the search of adaptive accounts, do exist. However, it is not a danger that is peculiar to methodological adaptationism, and Lloyd fails to explain how the alternative approach, i.e., the evolutionary factors framework, could avoid these dangers better. Hence, it should not be regarded as a good reason to attack methodological adaptationism and support the evolutionary factors framework. 3) Some of the dangers, such as the inability to evaluate evidence for non-adaptive hypotheses, result from an oversimplified interpretation of the research methods under methodological adaptationism. Although an adaptive hypothesis usually takes natural selection as the major factor for the evolution of a trait, it doesn’t have to exclude other possible evolutionary factors. In fact, testing an adaptive hypothesis usually involves the consideration and testing of other alternative factors. In sum, methodological adaptationism would not be so dangerous as Lloyd describes if it can be properly conceived and carefully employed.
Lloyd, E. A. (2015). Adaptationism and the logic of research questions: How to think clearly about evolutionary causes. Biol Theory, 10, 343-362.
Godfrey-Smith, P. (2001). Three kinds of adaptationism. In: Orzack, S. H. & Sober, E. (eds.) Adaptationism and Optimality. Cambridge University Press, Cambridge, pp. 335-357.
Gould, S. J. & Lewontin, R.C. (1979). The spandrels of San Marco and the Panglossian paradigm: a critique of the adaptationist programme. Proc. R. Soc. Lond. B, 205, 581-598.
Department of Philosophy
University of Pennsylvania