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Intelligence: Nature or Nurture?

One of the main bio-sociological debates entails the question of whetheror not intelligence is the result of genetics or the design of environmentalactors. While there is much evidence weighting to support both claims,

some believe in the predominance of one of the factors.here is much debate mong researchers and scientists over whichin!uence, genetics or environment, has the largest role in determiningoverall intelligence, because both have been scienti"call# established ashaving an impact on intelligence.

NatureHeritabilityhe natural genetic ma$e-up interacts with environment from the momentof conception. % geneis the unit of heredit# b# which a biological trait ispassed down through generations of human beings. &eritabilit#describeswhat percentage of the variation of a trait in a population is due to geneticdi'erences in that population (as opposed to environmental factors).

win studies in the western world have found the heritabilit# of I*to bebetween +. and +., meaning that the variance in intelligence among thepopulation is +-+ due to genetics. /onventional twin studiesreinforce this pattern: mono0#gotic (identical) twins raised separatel# aremore similar in I* than di0#gotic (fraternal) twins raised together, andmuch more than adoptive siblings.

%s a stud# b# a team of UCLA University of California (1++2) shows,human intelligence is highl# heritable and geneticall# determined. his isdue to the qualit# of axons in the white matter of the brain which isstrongl# controlled b# genetic factors. he a3ons are the transmitters anddecoders of the e3ternal stimulations an individual ma# come across. Itshows that the lesser the qualit# of the a3ons, the slower the braindevelops and matures to full# comprehend comple3 thoughts and$nowledge. he qualities of an individual4s a3ons are completel# geneticand cannot be modi"ed in an# wa#. herefore, it is proven that ever#oneis born with di'erent I* levels geneticall# programmed that cannot be

altered.

5ource: 6/7%

Nurture

Biological Inuences8iological in!uences include ever#thing from nutrition to stress, and beginto shape intelligence from prenatal stages onward. Nutrition has beenshown to a'ect intelligence throughout the human lifespan9 malnutrition

during critical earl# periods of growth (particularl# the prenatal period andduring the second #ear of life) can harm cognitive development.

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Inadequate nutrition can disrupt neural connections and pathwa#s, andleave a person unable to recover mentall#.

Stress5tress also pla#s a part in the development of human intelligence:e3posure to violence in childhood has been associated with lower schoolgrades and lower I* in children of all races. % group of largel# %frican%merican, urban "rst-grade children and their caregivers were evaluatedusing self-report, interview, and standardi0ed tests, including I* tests. hestud# reported that e3posure to violence and trauma-related distress in#oung children was associated with substantial decreases in I* andreading achievement. 3posure to to3ins and other perinatalfactors havealso been proven to a'ect intelligence, and in some cases, cause issuessuch as developmental dela#s.

Dr ic! Heber"s #il$au!ee %ro&ect

%lthough proven that biological factors ma# also pla# some part indetermining human behaviour, it is proven that our intelligence can betrained and pushed to higher levels. he results based on Dr ic!Heber"s #il$au!ee %ro&ectshows to stand for the latter. &e conducteda case stud# on ' ne$borns from #il$au!eewhose parents had I*lower than +and found that the care and love provided, in other words,the primar# socialisation, is essential to a child4s mental development.

,arly Socialisation

he famil# unit is one of the most basic in!uences on child development,but it is di;cult to untangle the genetic from the environmental factors ina famil#.

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told the# are intelligent, the# will appear more intelligent on I* tests9 ifthe# are told the# belong to a group that is unintelligent, the# will performworse, even if these distinctions are random and fabricated (as in labstudies). eople=s access to education, and speci"c trainingand interventionresources, also determines their life-long intelligence

level.

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