Questions on: Intelligence
I recently learned in my Psychology class of the "Flynn effect" named after James. R Flynn (1984, 1987, 1999). My book claims that the Flynn effect shows a global increase in intelligence test scores of about 3 points per decade. It doesn't mention which tests specifically, but they were specific enough in their point that intelligence is on the rise. The book attempts to explain it by saying that this improvement is due to increasing global complexity, with each person being exposed to a greater amount of information throughout his or her lifetime. They also said it could be caused by a widespread increase in nutrition throughout a person's life, including growth and maturation. They sited Dickens & Flynn, 2001; Neisser, 1997, 1998 for more information. This is in direct contradiction to what you have said, so I thought I'd bring it to your attention.
William Dickens and James Flynn set out to prove the effect of environment upon intelligence; being that this has been common knowledge in the scientific community for over seventy years (H.M. Skeels originally established this fact in practical experiments, followed by many others), I am unsure as to why this modern study attracts any attention.
There are several reasons why the Dickens and Flynn statistical research cannot be broadened to apply to intelligence in general. First, the work focuses on IQ tests, rather than the percentile scale. IQ testing is strictly used for comparing the development of children, and compares mental age to chronological age; obviously this does not work outside of a structured educational environment. As well, adults cannot be measured on such a scale: a fifty year old who scores well does not then have the mental ability of a seventy year old - this would be, considering the effect of ageing on the brain, contradictory.
The analysis was based on the scores of children in only twenty select nations, and covers several generations. Unfortunately, we did not have an accurate IQ test until the early Seventies. The original Binet-Simon test (and its variants) used earlier was seriously flawed, and was more a reflection of one’s command of the written English language and culture, than a true measure of intelligence; consequently, it was originally assumed that immigrants and members of ethnic cultures (that had no access to adequate education or nutrition) were mentally inferior to “White Anglo-Saxon Protestants”. Pre-1970’s tests cannot be compared to post-1970’s tests, there is no true correlation (although the Binet-Simon test is, surprisingly, still used in some places).
Naturally, nations that have improved their standard of living over time will yield progressively higher IQ scores due to the availability of structured learning environments and improved nutrition. Conversely, nations in decline will demonstrate a decrease in IQ scores. All cultures outside of the “Developed” nations will show a higher IQ level, based on the modern (images only) testing method, than was shown by the old written testing done prior to the Seventies.
And finally, I would suggest that Dickens and Flynn have not proven their hypothesis that intelligence is more a matter of environment than genetics. As with all the practical research done prior to their statistical analysis, all that has been established is that a favourable environment allows an individual to realise their genetic potential.
Neisser’s work is merely a reiteration of the ideas put forward by Charles Spearman, and later Raymond Cattell. This has to do with there being types of intelligence, rather than one overall measure. It never ceases to amaze me how we routinely forget the knowledge of the past, although the records still exist.
The one-percent-per-decade statistic I quote is from projections made based on data from 1971 to present. A 2001 study suggests a decline of 30 percent during that interval, but I am awaiting verification of this in further independent research before assuming its accuracy. More significant is the anthropological evidence showing that human brain size has consistently decreased over the past ten thousand years. It appears that the beginning of this decline corresponds to man’s “domestication”. Anecdotal evidence is to be found throughout recorded history, where philosophers of all ages and cultures have complained about the decrease in intelligence evident (to them) in the passing of each generation, despite the advancement of civilisation. Intellectuals of their time, such as Plato, even put forward the idea of using eugenics to curb this trend.. [back to FAQ index]
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