Adaptationism

Adaptationism is a scientific perspective on evolution that focuses on accounting for the products of evolution as collections of adaptive traits, each a product of natural selection with some adaptive rationale or raison d'etre.[1][2][3][4]

A formal alternative would be to look at the products of evolution as the result of neutral evolution, in terms of structural constraints, or in terms of a mixture of factors including (but not limited to) natural selection.[4]

The most obvious justification for an adaptationist perspective is the belief that traits are, in fact, always adaptations built by natural selection for their functional role. This position is called "empirical adaptationism" by Godfrey-Smith.[5] However, Godfrey-Smith also identifies "methodological" and "explanatory" flavors of adaptationism, and argues that all three are found in the evolutionary literature (see [1] for explanation).

Although adaptationism has always existed— the view that the features of organisms are wonderfully adapted predates evolutionary thinking— and was sometimes criticized for its "Panglossian" excesses (e.g., by Bateson or Haldane), concerns about the role of adaptationism in scientific research did not become a major issue of debate until evolutionary biologists Stephen Jay Gould and Richard Lewontin penned a famous critique, "The Spandrels of San Marco and the Panglossian Paradigm". [6] According to Gould and Lewontin, evolutionary biologists had a habit of proposing adaptive explanations for any trait by default without considering non-adaptive alternatives, and often by conflating products of adaptation with the process of natural selection. They identified neutral evolution and developmental constraints as potentially important non-adaptive factors and called for alternative research agendas.

This critique provoked defenses by Mayr,[2] Reeve and Sherman [3] and others, who argued that the adaptationist research program was unquestionably highly successful, and that the causal and methodological basis for considering alternatives was weak. The "Spandrels paper" (as it came to be known) also added fuel to the emergence of an alternative "evo-devo" agenda focused on developmental "constraints" [7] Today, molecular evolutionists often cite neutral evolution as the null hypothesis in evolutionary studies, i.e., offering a direct contrast to the adaptationist approach.[8][9] Constructive neutral evolution has been suggested as a means by which complex systems emerge through neutral transitions, and has been invoked to help understand the origins of a wide variety of features from the spliceosome of eukaryotes to the interdependency and simplification widespread in microbial communities.[10][11]

Today, adaptationism is associated with the "reverse engineering" approach. Richard Dawkins noted in The Blind Watchmaker that evolution, an impersonal process, produces organisms that give the appearance of having been designed for a purpose.[12] This observation justifies looking for the function of traits observed in biological organisms. This reverse engineering is used in disciplines such as psychology[13] and economics[14] to explain the features of human cognition. Reverse engineering can, in particular, help explain cognitive biases as adaptive solutions that assist individuals in decision-making when considering constraints such as the cost of processing information. This approach is valuable in understanding how seemingly irrational behaviors may, in fact, be optimal given the environmental and informational limitations under which human cognition operates.

  1. ^ a b S. H. Orzack and P. Forber (2017). "Adaptationism". In E. N. Zalta (ed.). The Stanford Encyclopedia of Philosophy.
  2. ^ a b E. Mayr (1983). "How to carry out the adaptationist program?". Am. Nat. 121 (3): 324–334. doi:10.1086/284064.
  3. ^ a b H. K. Reeve and P. W. Sherman (1993). "Adaptation and the Goals of Evolutionary Research". Quarterly Review of Biology. 68: 1–32. doi:10.1086/417909.
  4. ^ a b E. A. Lloyd (2015). "Adaptationism and the Logic of Research Questions: How to Think Clearly About Evolutionary Causes". Biological Theory. 10 (4): 343–362. doi:10.1007/s13752-015-0214-2.
  5. ^ P. Godfrey-Smith (2001). "Three Kinds of Adaptationism". In S. H. Orzack and E. Sober (ed.). Adaptationism and Optimality. pp. 335–357. doi:10.1017/CBO9780511609084.012. ISBN 978-0-521-59166-9.
  6. ^ S. J. Gould and R. C. Lewontin (1979). "The spandrels of San Marco and the Panglossian paradigm: a critique of the adaptationist program". Proc. R. Soc. Lond. B. 205 (1161): 581–598. Bibcode:1979RSPSB.205..581G. doi:10.1098/rspb.1979.0086. PMID 42062.
  7. ^ R. Amundson (2005). The Changing Role of the Embryo in Evolution. Cambridge University Press, Cambridge, UK.
  8. ^ Koonin, Eugene V. (2016-12-23). "Splendor and misery of adaptation, or the importance of neutral null for understanding evolution". BMC Biology. 14 (1): 114. doi:10.1186/s12915-016-0338-2. ISSN 1741-7007. PMC 5180405. PMID 28010725.
  9. ^ L. Duret (2008). "Neutral theory: The null hypothesis of molecular evolution". Nature Education. 1: 218.
  10. ^ Lukeš, Julius; Archibald, John M.; Keeling, Patrick J.; Doolittle, W. Ford; Gray, Michael W. (2011). "How a neutral evolutionary ratchet can build cellular complexity". IUBMB Life. 63 (7): 528–537. doi:10.1002/iub.489. PMID 21698757. S2CID 7306575.
  11. ^ Brunet, T. D. P.; Doolittle, W. Ford (2018-03-19). "The generality of Constructive Neutral Evolution". Biology & Philosophy. 33 (1): 2. doi:10.1007/s10539-018-9614-6. ISSN 1572-8404. S2CID 90290787.
  12. ^ Richard Dawkins (1986). The Blind Watchmaker. London: Longman.
  13. ^ Tooby, John; Cosmides, Leda (1992). "The Psychological Foundations of Culture". In Barkow, Jerome H.; Cosmides, Leda; Tooby, John (eds.). The Adapted Mind: Evolutionary Psychology and the Generation of Culture. New York: Oxford University Press. pp. 19–136. doi:10.1093/oso/9780195060232.003.0002. ISBN 9780197736944.
  14. ^ Page, Lionel (2022). Optimally Irrational. Cambridge: Cambridge University Press. doi:10.1017/9781009209175. ISBN 9781009209175.