The Seven Sins of Evolutionary Psychology - Konrad Lorenz Institute

Ian Pitchfordother biological resources, patterns of maternalcare, play, and so forth can ‘mutate’ producingnovel phenotypic characteristics. In contrast to theperspective encouraged by the ‘genetic blueprint’ or‘genetic program’ metaphors, this approach allowsfor phenotypic variability, and for constant, stableoutcomes, provided that all of the resources requiredby the developmental system are available(GRIFFITHS 1997, p186). This theory is applicable tothe whole of evolutionary biology, and not only tothe neocortex as the PANKSEPPs seem to think.Perhaps the most insidious consequence of thegenetic blueprint idea is the expectation that phenotypiccharacteristics are innate, meaning ‘hereditarilydetermined’, or arising independently of environmentor experience (LEHRMAN 1953). Describinga trait as ‘innate’ confuses at least four propertiesthat can vary independently: “(1) that it is found inan individual because of their ancestry rather thantheir current environment; (2) that its growth doesnot depend on that environment for anything butbasic sustenance; (3) that it is present at birth or earlyin development; and (4) that it is part of the ‘nature’of the species… The result of this mismatch betweenconcept and reality is that when theorists discoverthat one element of the innateness concept appliesto a trait, they are liable to assume that the otherelements must also apply” (GRIFFITHS 1997, p104).Our faculties are the product of developmental systems,and consequently they are neither innate norstructured by the environment. The PANKSEPPs formulationperpetuates the very ‘nature versus nurture’dichotomy that developmental systems theoryaims to transcend.Adaptations, Exaptations, and SpandrelsThe PANKSEPPs are surely correct that we should beconfident where convergent lines of evidence pointin the same direction, which makes their assertionthat recent brain evolution is characterised by “therapid expansion of general-purpose cortico-computationalspace (which permitted the emergence offoresight, hindsight and language)” appear strikinglyincongruous. The obfuscations of those wholike to characterise themselves as opposed to ‘DAR-WINIAN fundamentalism’ (GOULD 1997) play a rolehere. The PANKSEPPs tell us that “since the emergenceof massive, general-purpose cortical space, exaptationsand spandrels have arisen everywhere welook”. Their mentor GOULD (1984) does not disagreewith biology’s emphasis on natural selection but believes“that we have become overzealous about thepower and range of selection by trying to attributeevery significant form and behavior to its direct action”.Obviously, we should not be interested in ‘attributing’anything at all to natural selection. Weneed to look at the evidence that “a function isserved with sufficient precision, economy, efficiency,etc. to rule out pure chance as an explanation”(WILLIAMS 1996, p10).In their original paper on ‘spandrels’ GOULD/LEWONTIN (1979) make entirely prosaic observationsconcerning the ubiquity of phyletic constraints, andargue that the evidence for Aztec cannibalism, thechin, and papillary ridges as adaptations is notstrong. In a second paper cited by the PANKSEPPsGOULD (1991) observes that ‘exaptations’ can be definedas characters not selected for their currentfunction which may or may not have arisen originallyby the direct action of natural selection. Usefulcharacters that did not arise by the action of naturalselection are a type of exaptation, or coopted nonaptation,called a spandrel. GOULD mentions weight,the delayed ossification of skull bones, and languageas probable exaptations.It seems clear from these examples that (with theexception of language, which appears to share littlein common with the other examples) spandrels aretrivial features that would not be identified as adaptationsby anyone using the conventional criteria. Itis equally clear that we have no good reason to restrictthe term ‘adaptation’ to only those charactersthat perform the function for which they were firstselected. As GRIFFITHS and STERELNY point out“GOULD and VRBA think that a trait is an adaptationonly for the purpose for which it was first selected.But what justifies this special status for the first ofmany selection pressures? The importance of theconcept of adaptation in biology is that it explainsthe existence of many traits of the organisms we seearound us. This explanation is not just a matter ofhow traits first arose, but of why they persisted andwhy they are still here today” (STERELNY/GRIFFITHS1999, p219). The only complex functional characteristicclaimed as an exaptation is language, andthis is done by argument from authority—the authorityin question being CHOMSKY, who is said tohave “long advocated a position corresponding tothe claim that language is an exaptation of brainstructure” (GOULD 1991, p61). However, CHOMSKYhas not “expressed views on the lack of a role fornatural selection in… the origin of language”. Onthe contrary he believes “that natural selection isoperative in this case” (personal communication1999).Evolution and Cognition ❘ 40 ❘ 2001, Vol. 7, No. 1