In this essay I will discuss and critically analyse the Nature-Nurture debate. This essay contains relevant information regarding each perspective and theorists involved as well as evidence to support the pertinent facts from each perspective. The 'Nature-Nurture' debate is principally concerned with hereditary (nature) verses environmental influences (nurture) and particularly in this case, how each influences development of human intelligence.
Theorists such as Herrnstein & Murray as well as Jenson do not support educational programs for underprivileged groups since "intelligence cannot be increased noticeably because a child's genetic destiny cannot be altered" (Weiten. 2001).
Paradoxically theorists such as Angoff and Wahlstein support the concepts of remedial educational programs and various roles these programs play in an effort to improve lower-class schooling in financially troubled neighbourhoods. (Weiten, 2001)Twin studies have been utilised due to the fact that families share more than just genes -they most probably share the same environment. By simply analysing family studies, one would not be given a purely objective testing method as the factors of environment would be ignored while evaluating hereditary influence on intelligence. The value of twin studies is immeasurable as it provides the opportunity to compare genetic relatedness and similar environments, whether in terms of behaviour or in this case, to analyse levels of intelligence.
"In twin studies researchers assess hereditary influence by comparing the resemblance of identical twins and fraternal twins with respect to a trait" (Weiten, chapter 3, p105).
Critics of twin studies argue that identical twins are more alike in IQ because parents and others treat them more similarly than they treat fraternal twins. Support could be made that identical twins are the same gender and are therefore brought up in the same manner, but at the same time, this could be rebutted by the unlikelihood of separated identical twins having a very similar IQ. (Weiten)A " 'Heritability Estimate' is an estimate of the proportion of trait variability in a population that us determined by variations in genetic inheritance" (Weiten ch9 pg 365).
The estimate varies greatly amongst theorists (some like Jenson claim it as high as 80%, construing environment to influence only 20% of intelligence whereas Devlins, Daniels and Roeder have claimed estimates as low as 48% suggesting heredity has a substantial influence on a person's intelligence). (Weiten)Evidence for Environmental influence also uses adoption studies, environmental deprivation and enrichment, as well as Home environment and schooling and generational changes (the Flynn Effect).
Generally the studies done have shown that parents upbringing and a child's home environment affect their intelligence greatly. Children from the same house will be similar in IQ compared to those siblings reared apart. (Lourto, 1990; Loehlin, Horn, & Willerman...