The Seven Sins of Evolutionary Psychology - Konrad Lorenz Institute

Scott AtranThe Case for Modularity: Sin or Salvation?IntroductionThe central thesis ofPANKSEPP and PANKSEPP(2001, henceforth, P&P)is that there are no speciallyevolved, higher-orderdomain-specificcognitive mechanisms tospeak of. Apart from thebasic DARWINIAN emotions(fear, surprise, anger,sadness, joy, disgust),so-called cognitive ‘modules’are more likely “theproduct of dubious humanambition ratherthan sound scientific reasoning”.What evolutionarypsychologists (as wellas many cognitive anddevelopmental psychologists)take to be modularstructures are actually theepigenetic products ofthe ancestral emotionalfunctions of the brain(rooted in what was oncecalled “the limbic system,”MACLEAN 1990)and more recent “general-purposebrain mechanisms”.In more than a dozen places, P&P repeat asmantra that empirical evidence indicates the modernhuman mind was created through the dualfunctioning of subcortical mammalian emotionsand a neocortical general-purpose computationaldevice. Furthermore, this highly flexible, all-purposeintelligence probably emerged “more rapidlyvia group selection than by individual selection”.There is much to commend the cautionary talethat P&P tell regarding possible excesses of sociobiologicalspeculation, including what are arguably‘just-so’ stories about modularized adaptations forAbstractThe case for evolved cognitive modules rests on severalconverging lines of evidence: Functional design(analogy), ethology (homology), universality, precocityof acquisition, independence from perceptual experience(poverty of stimulus), selective pathology(cerebral impairment), resistance to inhibition (hyperactivity),ease of cultural transmission. No factor maybe necessary but evidence for all or some is compelling,if not conclusive, for domains like folkmechanics,folkbiology, folkpsychology. By constrast, noempirical evidence supports PANKSEPP and PANKSEPP’scentral thesis: that what evolutionary psychologists(and many cognitive and developmental psychologists)consider modular structures are actually epigeneticproducts of subcortical mammalian emotionsand neocortical general-purpose computations. Arguably,no significant empirical discovery about languageor other higher-order cognitive structures yetowes to inquiries about evolutionary origins and functions.Nevertheless, adopting evolutionary psychology’srequirement that candidate exaptations andspandrels be described, as far as possible, in connectionwith evolved adaptations, opens new avenues forexploring and testing modular designs.Key wordsModularity, domain-specificity, language, folkpsychology,folkbiology.Evolution and Cognition ❘ 46 ❘ 2001, Vol. 7, No. 1rape (THORNHILL/PALMER2000), homicide (BUSS1999) and emotional disorderssuch as depression(NESSE/LLOYD 1992).P&P’s position on the derivativeand epigeneticcharacter of ‘secondary’or ‘social’ emotions (guilt,love, empathy, etc.), isalso defensible (e.g., DAM-ASIO 1994), although seriouslydebatable (cf.LEDOUX 1996; GRIFFITHS1997). Finally, P&P’s takeon the current, overlyfundedfad for neuroimaging(driven more bytechnological innovationand the industry it supportsthan by any theoreticalinsight) is credible.There can no more be atheory directly derivedfrom observations of neuroimagingthan there canbe a theory derived directlyfrom observationsof meter readings; it isonly in the service ofsome prior abstract theorythat such observationscan make sense. Nevertheless, there is no empiricalevidence whatever to indicate that P&P’scentral thesis is true, and much to suggest it is false.Evolutionary Psychology:No Explanatory Value forHigher-Order Cognition (Yet)To-date, evolutionary psychology has not predictedor discovered any significant or surprising aspect oflanguage or higher-order cognitive devices of thesort I describe below. But this does not mean that all