Psychologist Richard Nisbett’s February 2009 book, “Intelligence and How to Get it”, looks at the important contribution experience and environment make to IQ. In the book, he argues that the commonly held view that genes are the main determinant of intelligence is mistaken. His critique centers on flaws in the research. Most research, according to Dr. Nisbett, focus on twins raised in “different” environments. The problem is that kids raised apart tend to be in very similar environments. When studies look at kids who have been raised in very dissimilar environments, a large discrepancy in measured IQ scores is seen. More specifically when a subset of kids are studied, for instance, when poor kids are adopted into upper middle class families, the typical increase in IQ is 15 points. In addition, Dr. Nesbitt notes that if people at the beginning of the 20th Century were given today’s IQ measure, half would be considered mentally retarded. Clearly, culture and education has had an impact.
The debate about the greater impact of genes versus environment should have been resolved some time ago. Trying to isolate genes from experience is very difficult in that there is a moment to moment interaction between the two that makes them intricately intertwined and in many ways inseparable. Arguments persist due to the socio-political implications of giving greater import to one over the other. If genes are the main determinants of intelligence then, by extension, we should not be wasting money trying to improve the impoverished environments in which many kids grow up. Why waste tax dollars? Dr. Nisbett’s book notwithstanding, the general trend over the last 20 years has been to over-emphasize genetics. This is due to the improved technology that is allowing us to take a closer look at genes and their potential impact on behaviour, as well as due to the conservative political trends that have predominated over the past twenty years. The general tenor of our times is one of neurogenetic determinism. The problem is that this lack of balance tends to lead to a polarization of the arguments on either side.
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