Genetics of Human Behaviour

8/8/2019 Genetics of Human Behaviour

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Genetics of human behaviourJ oa nn a Monc rie ff

Asc rib ing human behav iou r t o t he in flu ence o f g ene ti cfactors is a reductionist idea that inapprop riate lya pp lie s th e e xp la na tio ns o f p hysica l scie nce to th ehuman social world. Theresu lt i s that the designa tion ofs ome b eh av io ur a s d ev ia nt is d isg uis ed a s o bje ctiv escience. Theh igh pro fi le o f genet ic research means tha twe must b e a le rt t o th e pot en tia l s oc ia l c on sequence so f th is t yp e o f r ea soning .

The increasing technical sophistication withwhich genetic research can now be conductedhas raised its scientific and public profile. TheHuman Genome Project has been widelyheralded as the ultim ate biological endeavourand one that w ill unfold the secrets of life itself. Itw as therefore predictable that the question of thegenetic origins of human behaviour should againbecom e prom inent. R ecent commentaries indicate that genetic explanations and solutions area lready being g reeted with unc ritic al enthus ia smin some quarters. S peculation about an X -linkedpattern for the inheritance of 'genius' in thefam ily of Erasm us and Charles D arw in has beenpublished recently (Turner, 1996). In thepsychiatric literature, Huxlean visions of atechnology of behavioural m anipulation using

drugs to correct for the consequences of havingthe w rong sort of genes, have been applauded(Farmer & Owen, 1996). These ideas arereminiscent of the socio-biology of the 1970swhich in turn recalled eugenics movements ofthe past. Although these ideas have beenthoroughly challenged and some would feeldiscredited (Lew ontin, 1980; Rose et al 1984),modern molecular genetics has given them a newguise and w ith th is a n ew resp ectab ility.

Positiv ism and r educ tionismThe belief that patterns of hum an behaviour canbe explained by genetics is a type of biological'reductionism'. This phrase has been coined to

convey the manner in which the complexphenomena o f human so cia l activ ity is explain edw ith reference to biochem ical events and henceultimately in terms of the laws of physics.Reductionism can be seen, in turn, as a form ofpositivism , a creed that recommends the application of the principles of physical science to thestudy of the hum an social w orld. There has been

a sustained and wide-ranging challenge topositivism, since its inception, from withinphilosophy and social science. However, thisterritory is unfamiliar to areas that are considered to be physical sciences, and hence it isworthwhile reviewing the a rgumen ts .Opponents of positivism argue that there is a

fundamental distinction between the type ofexplanation required in the physical w orld andthat w hich is appropriate to human behaviour

(examples include Winch. 1958: Heidgegger,1962; Taylor. 1964; Dilthey, 1989). The aimsof physical science, our interaction with thematerial environment, are effective predictionand manipulation which require that we areable to generalise findings from one situation toanother. The categories we have formulated todescribe the physical world in science aretherefore constructed to reflect the constantaspects of physical phenomena. They embodyour understanding of objectivity, that is theydescribe features that are uniform , generalis-able and appear the same to different observers.O bjectivity im plies that events can be conceptualised independently of the investigator andthe process of investigation. The concept ofcausation in physical science emerges fromthese considerations. An event can be considered causal to the extent that it consistentlypredicts another event in a way that can bereplicated or generalised. The explanation isindependent of the time and place of theparticular observation.It is not clear that this paradigm can sensibly

be imported into the realm of social understanding. In the case of physical science, theob jec t o f i nvestig ation , th e material world , can b econtrasted to, or set apart from, human beingsas a whole. Scientific constructions of it aretherefore, in theory, available to everyone. Incontrast, a universal or objective perspective isnot available in the study of hum an behaviour asthe object and agent of investigation are of thesam e world. The acquisition and construction ofknow ledge about hum an beings cannot involveeve ryone equally a s it has a d iffe rent re la tionshipto d ifferen t p eop le . Some people are con stitu tedas objects of study by others that are theinvestigators or subjects .Now human beings, as all organisms, are

nec essarily d ifferent from one anoth er. D iv ersity

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is intrin sic to living systems. It is the propertythat enables each indiv idua l to d iffe rentia te h imor herself from others. The m anner in whichthis diversity is ordered by the human m ind isnot d ictated by the phenomena themselves, butby the social context which involves, mostimportantly, the needs and interests of thesoc ia l group . The dis tinctions we make betweenthe normal, the accep tab le o r the desirab le andthe deviant or unwanted are not impartial.Diffe rent groups with in soc ie ty, who have theirown particular interests, will interpret andrespond to the same behaviour differently.Types of behaviour that seem problem atic tosome will be regarded as advantageous byothers. An act of behaviour may be labelled asaggressive, for instan ce, in some situatio ns toconvey disapproval but the same action in ad ifferen t contex t may be heralded as hero ic.The issue of agency is also central to this

debate. Human beings , as all liv ing o rgan isms,are agen ts who make choices and who in fluencetheir environment through these choices . Again ,agency is a characteristic that distinguishesliving organisms from inorganic matter. Inphysical science, concepts of prediction andcausation are deterministic - they deliver acer ta in outcome for a given set ofcircumstances.In contrast the agency or intentionality ofbehaviour ensures that "it is in the nature ofliving organism s that their future is indeterminate" (Rose. 1997). We canno t, in p rincip le,know the outcome of a situation involving human beings or any living organism , even if w ecould ascertain all possible contingencies.Indiv idual human actions canno t be described

as being caused by someth ing in the same way asphysical events can be. Human behaviour ischosen, not determ ined and hum an history iscreated not predestined.

Gene ti cs as reduc tion ismGenetic reductionism loca tes the explana tion ofthe phenomena of human behaviour at the levelof the genetic code. This obscures the complexsocial processes that are involved in defining andunders tanding behav iour. It therefo re d irectsattention away from the social context or thestate o f society to the b io logy o f the indiv idual.The indiv idua l is conceptualised as the problemfor so ciety rather than the p articular natu re of

society being seen as a problem for some of itsmembers (Lewon tin , 1993). In th is way geneticreductionism fosters a neglect of possibil it ies forsoc ia l change and thereby serves the in te rests ofthose who already benefit from the currenta rrangement of the soc ia l order.T he quest for the genetic origins of life also

encourages the d iv ision o f people acco rd ing toh ie ra rchies. If the Human Genome Pro ject fu lfi ls

expectatio ns, it w ill be possible to categorisepeople accord ing to how close they come to someidea l genetic type . People wil l be d iscriminatedon the basis of their degree of physical andmenta l genetic fi tness. Although th is h ie ra rchyhas the appearance of being derived fromb io logy, it is a socially constructed h ierarchy,which merely disguises the social values itencapsulates in biological language.The politica l issues invo lved are h ighlighted

when the intervention that is dictated by thereasoning of b io logical reduction ism is considered . The indiv idual becomes not only the focusof explanation, but also, logically, the primetarget of intervention. The proposal, m ade inth e 1970s, to u se psychosurgery to manage thed is ruptive behaviour of inner-c ity militants is acrude example (Mark & Erv in , 1970). However,recent advocacy of the use of drugs to correctundesirable behaviours arising from pu tativegenetic abnormalities is based on the samera tiona le (Farmer & Owen, 1996).It is clear from this discussion that the

discovery of biological correlates of humanbehaviour does not necessarily support theu tility o f the reductionist parad igm. B io logicalas sociations only re flect at the b io logical levelthe social and evaluativ e p rocesses that determine the s ignificance of d iffe rent behaviours . Inpract ice, b io logical, including genetic , assoc iations o fbehav iour have p roved hard to demonstrate consistently, although the contents ofevery major scientific , medical and psychia tr icjournal testify to the will and the resourcesdedicated to this search. In addition, thereduct ionist inference that genet ic associations,

if found, must be construed as causes ofbehaviour needs challenging further. The results of a certain genetic disposition cannot bean ticipated e ither in abso lu te terms o r in te rmsof conferring an increased risk of imposing ahypothetical lim it to capacities. Exp res sion o fgenes is influ enced by env ironmental circumstances which cannot be predicted becauseindividuals create their own environm entsthrough the choices they make. Rose et al(1984) explain succinctly that "the properdescription of the difference between genetictypes is not some hypothetical capacity but inthe specific phenotype that will develop for thatgenotype as a consequence of som e specificcha in of environmenta l c ircumstances". It is , in

principle, im possible to know the effect ofhaving a particular gene on an individual'sbehavioural propensities.

The case of beh avioural geneticsThe case o f behav ioural genetics illu strates thetenacity of the reductionist paradigm in the

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face of these challenges. Population researchand molecular genetic techniques are widelybelieved to have demonstrated the heritabilityo f cond itio ns su ch as sch izoph renia, d ep ressio n

and alcoholism , aspects of personality including intelligence, temperament and sexualo rien tation . However, p ositive fin dings are g iv enextensive publicity and are received enthusiastically and larg ely uncritic ally in th e scien tificpress. In contrast, thoroughly researched criti ca l expossof the epidemiolg ica! evidence inareas such as the inheritance of schizophreniaand intelligence are rarely acknowledged(G ould, 1981; Rose et al 1984). The fraudulentwork of Sir Cyril Burt was accepted for manyyears before being discredited, despite glaringom issions and inconsistencies (K am in, 1974).In addition, the highest available estimates ofheritability are most frequently quoted, theextent of non-genetic variation revealed is

played dow n and inconsistencies and negativefindings are circumvented. A host of theoriesare available to explain the inconsistency of theevidence with a clear genetic pattern of inheritance, such as the heterogeneity of thedisorder, partial penetrance, multifactorial inh eritan ce and genetic mutatio n.For example, based on certain twin studies,

schizophrenia is commonly asserted to be atleast 50% heritable. However, studies thatshow that sch izophren ia congreg ate s in fam iliesalso show that around 90% of people withschizophrenia do not have a first-degree relative with the disorder. High publicity hassurrounded claims from molecular geneticstudies to have identified relevant genes butlittle attention is paid when attempts atreplication fail. A recent pan-European molecular genetic study boldly concludes that theg enetic asso ciation s rev ealed are in vo lv ed in thepathogenesis of the disorder. However, incommon with much genetic research, thisproject suffered from some basic epidemi-ological problems. The comparability of thecontrol group was questionable, multiple hypotheses were tested, and other than ethnicorigin, there was no attempt to control forsources of confounding. In addition, the relevance of the findings is uncertain as the geneis common in the general population and wasobserved to be only slightly more common inpeople with schizophrenia (Williams et al1996).

ConclusionThe d ivers ity and inde te rminacy o f life constitu tethe basic parameters of human experience. T heyconstitute the foundations on which humancommunication and activity are predicated. B ut

th ey underm in e the assump tio ns of the po sitiv istenterprise. The search for laws as a basis ofgeneralisation and prediction cannot be reconciled w ith th e fac ts th at p eople are n ecessarilydifferent from one another and that a person'sdestiny is dependent on the choices theythemse lves make.C ritics of positivism have advocated a variety

of alternative paradigm s for understanding andinvestiga ting human behaviour including phenomenology, ethnomethodology and hermeneu tics.They all acknowledge the contingency andpartiality of the act of investigation and seek toexamine the specific context or antecedents ofbehaviour rather than pursuing generalities.The type of understanding appropriate for thehuman world is held to be different in kind fromthat required of the physical world, whereprediction and manipulation form the basis ofknowledge.

Positivism and reductionism are not politically neutral. The positivist paradigm, byconstituting some human beings as objects,underm ines the authority of their perspectiveand sets up the values of the investigators andtheir patrons as universal. Reductionism, bycasting social judgem ents as biological facts,obscures this process and thereby denies thelegitim acy of alternative perspectives thus stiflin g possibilitie s fo r soc ial ch ange. Increasin gtechnological sophistication and scientific enthusiasm mask the dubious foundations ofbehavioural genetics. H owever, the eugenicsm ovem ents of the late 19th and 20th centuries,have already amply demonstrated the type ofpolitical interests that are served by thisideology. The scientific community must endits complacency and recognise the relevance ofthe debate about positivism and the critique ofbiological reductionism for research into theorigins of human behaviour. Otherwise itcontinues to reinforce possibilities for stigmatisa tion and repre ss ion.

ReferencesDILTHEY.W. (1989) Introduction to the Human S cie nces (eds

R. A. M akkreel & F. Rodi). Princeton. NJ: PrincetonUniversi ty Press .

FARM ER.A. & OWEN. M . J. (1996) Genomics: the nextp sy ch ia tr ic re vo lu tio n? B rifis li J ou rn al o f P sy ch ia try,169 . 1 35 -138 .

GOULD. S. J. (1981) The M ism easure of M an. New York:Norton.

HEIDOEGGER.M . (1962) B eing and Tim e. New York: Harperand Row.

KAMIN .L . J . (1 974) The Scie nc e and Politic s o fl.Q . London:Wiley.

LEWONTIN ,R . C . (1980) Soc iobio logy : a no th er b io logic aldeterm inism . Jntemafion al Journal of H ealth S ervices,10. 347-363 .

1993) The Doc tr in e q fDNA. London: P engu in .

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MARK.V. H. & ERVIN.F. R. (1970) Violence and the Brain. receptor gene. European Multicentre AssociatioNew York: Harper and Row. Study of Schizophrenia (EMASS) Group. Lancet. 347.

ROSE. S. P. R. (1997) Lifelines: Biology. Freedom and 1294-1296.Determinism (in press). London: Penguin. WINCH. P. (1958) The Idea of a Social Science. London:

LEWONTIN.R. C. & KAM IN,L. J. (1984) Noi in Our Genes. Routledge and Kegan Paul.

London: Penguin.TAYLOR,C . (1964) T he Exploration of B ehaviour. N ew York:R outled ge and Kegan P aul.

TURNER, G. (1996) Intelligence and the X chromosome. Joanna Moncrieff, Research Fellow andLancet. 347. 1814-1815. .-, . . . fW.LL1AMS... SPURLOCK.. . McGuFFiN.P.. et al (1996) Honorary Sentar Registrar, Section ofAssociation between schizophrenia and T102C Epidemiology and General Practice. Institute ofpolymorphism of the 5-hydroxytryptamine type 2a- Psychiatry, London SE5 8AF

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Genetics of Human Behaviour