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createagenius.ItisnoticeablethatgeneralIQisnotanemergenictrait,whereasexcep-
tionalabilitiesandtalentsare.However,anabove-averagelevelofintelligenceisbe-
lievedtobeacriticalconditionforthedevelopmentofanemergenictalent.Somepsy-
chologistsclaimthatthereisathresholdinIQlevel,abovewhichitdoesnothavean
influenceonachievements.Worthmentioningistheobservationthatintelligenceisnot
equallyimportantineverydomainofability.Forexample,musical,mathematicaland
achievementsinthefieldofhumanitiesareconnectedwithIQ,whereassomespecific
artisticabilities,forexamplesculpture,arenot(cf.Sękowski,2004).
Anotherbiologicalbasisofindividualdifferencesincognitiveabilitiesisconnected
withtheneuralsystemfunctioning.Asregardstheneuralsystem,therearethreesources
ofabilitydifferentiation:neuralconductionvelocity,neuralefficiencyandbrainvolume.
AsJensen(1998,2002)convincinglyargues,allthevariationinmentalperformancehas
abiologicalbasis.HeelucidatesthatthereisanegativecorrelationbetweentheIQand
thereactiontimeofaperson.ThatmeansthatthehighertheIQlevelofapersonis,the
lesstimehe/sheneedstosolveaproblem.Hisargumentsarebasedoncorrelationsbe-
tweenmagneticresonanceimaging(fMRI),electroencephalogram(EEG),eventrelated
potential(ERP),emissiontomography(PET)
7,andstudiesofnerveconductionvelocity
andIQ.Jensenclaimsthatbesidesthespeedofneuralconduction,IQcorrelateswiththe
efficiencyoftheprocess.Inotherwords,intelligentpeoplereactnotonlyfaster,butalso
moreregularlyincomparisontolessintelligentones.Thisstatementiswell-evidenced
intheliterature(cf.Nęcka,2003).Asystemthatismoreefficient,namelymoreresistant
todistraction,producesmoreregularreactions,which,consequently,shortensthetime
ofreactionaslesstimeisspentonsubsequenttrials.Thebiggestadvantageofsuch
averyefficientsystemisahigherlevelofcompetencetosolvedifficult,complexmental
problems.Briefly,asystemmoreefficientintransmittingnervousimpulsesisamore
intelligentone.
ThefMRIstudybyHaieretal.(2004)demonstratedthatgeneralIQappearstobe
basedonthevolumeandlocationofgraymattertissueinthebrain.Manystudieshave
convergedontheviewthatthefrontallobesarecriticalforfluidintelligence,specialrole
beingattributedtothelateralprefrontalcortex(Schoenemann,Sheehan,&Glotzer,
2005).Moreover,thefMRImethodhasprovidedevidencethatindividualsmoreadeptat
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7PET(positronemissiontomography)isusedforlocalisationofdifferentneuralfunctionsbymeansof
injectionofradioactivetracers.Moreactivebrainareashavehigherlevelsofbloodflowand,conse-
quently,ofthetracer.Bycreatingpicturesofthetracerdistribution,aneuroscientistcanobtainapat-
ternofbrainfunctioning.fMRI(functionalmagneticresonanceimaging)givessimilarresultstoPET,
butreliesonmeasuringthemagneticresonancesignalgeneratedbytheprotonsofwatermoleculesin
neurons.ERP(eventrelatedpotential)is,unlikePETandfMRI,basednotonlocalisationofneural
activity,butonthetimingofneuralevents.Electrodesplacedontheskinofthescalprecordactivity
ofthebrain.ThistechniqueisbasedonEEG(encephalography),buthasanexperimentaldesign
(Goswami,2004,pp.5-6).
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