Literacy Rates, the Flynn Effect, Brain Wiring, Tautologies

In a recent look at the Flynn Effect, we at Al Fin neglected to mention one of the possible important contributors to at least part of the changes in IQ test scores observed over the 20th century: changes in literacy rates.

World Literacy 1900s
In a trivial sense, if a test-taker is unable to read and understand the directions for taking the test, his test score would not be valid. IQ Corner blog presents an interesting discussion about the possible relationship between the Flynn Effect and literacy rates.

The importance of being able to read for performance on an IQ test cannot be understated. Instead of measuring ‘intelligence' in a nonliterate test-taker, the test is measuring that person's inability to read....If increasing literacy were really explaining a number of seemingly different IQ trends, then you would expect to see a few things. First, within a population you should expect increased education of literacy skills to be associated with an increase in the average IQ of that population. Second, IQ gains should be most pronounced in the lower half of the IQ bell curve since this is the section of the population that prior to the education would have obtained relatively lower scores due to their inability to comprehend the intelligence test's instructions. With increased literacy, you should expect to see a change in the skewness of the IQ distribution from positive to negative as a result of higher rates of literacy in the lower half of the IQ distribution (but very little change in the top half of the distribution). You should also expect to see differences on the particular intelligence test subscales, with increased literacy showing the strongest effects on verbal tests of intelligence and minimal differences on other tests of intelligence.

...To test these predictions, Marks looked at samples representative of whole populations (rather than individuals), and used ecological methods to calculate statistical associations between IQ and literacy rates across different countries. Were Marks' findings consistent with the predictions?

Strikingly, yes. He found that the higher the literacy rate of a population, the higher that population's mean IQ, and the higher that population's mean IQ, the higher the literacy rate of that population. When literacy rates declined, mean IQ also declined. Marks also found evidence for unequal improvements across the entire IQ spectrum: the greatest effects of increased literacy rates were on those in the lower half of the IQ distribution. Interestingly, he also found that both the Flynn Effect and racial/national IQ differences showed the largest effects of literacy on verbal tests of intelligence, with the perceptual tests of intelligence showing no consistent pattern.

It must be noted that literacy wasn't the only factor responsible for the Flynn effect. Adopting the Cattell-Horn-Carroll (C-H-C) framework (McGrew, 2005, 2009) Marks found that Visual processing (Gv) and Processing Speed (Gs) also made important contributions. _IQCorner

Recent research suggests that learning to read actually changes the physical structure of the brain, and consequently brain activity and processing. If that is the case, then the effect of literacy on IQ scores may extend far beyond the ability to understand the test instructions.

Reading and writing are cognitive tools that, once acquired, change the way in which the brain memorizes facts and conceptualizes ideas, and these changes stimulate abstract thinking. When psychologists use neuroimaging technology, like MRI, to compare the brains of literates and illiterates working on a task, they find many differences in how their brains work whether or not they are reading. Researcher Alexandre Castro-Caldas discovered that processing between the hemispheres of the brain was different between those who could read and those who could not. A key part of the corpus callosum was thicker in literates, and "the occipital lobe processed information more slowly in individuals who learned to read as adults compared to those who learned at the usual age." Psychologists Ostrosky-Solis, Garcia and Perez tested literates and illiterates with a battery of cognitive tests while measuring their brain waves and concluded that "the acquisition of reading and writing skills has changed the brain organization of cognitive activity in general… not only in language but also in visual perception, logical reasoning, remembering strategies, and formal operational thinking." Literacy — a human invention — rewires the human mind. _The Technium

Kelly goes on to point out that the study of music can also alter brain structure and brain function. Then he suggests that the internet and related communication and information technologies may be causing similar changes in the way the brain is wired, thus changing how (and how well) people think.

Children must be exposed to language by a certain age, or they will lose the ability to become skilled in its use -- presumably forfeiting any advantages in brain processing that language confers. The same is true for the timely learning of music, and the skillful development of musical talents. In fact, developmental windows exist for many cognitive skills -- both known and likely unknown (for now) skills.

This raises intriguing questions about what we could be doing -- but aren't -- to facilitate improved thinking skills for our children, and perhaps ourselves. Very few persons, if any, are consistently functioning at their peak cognitive levels. What training methods are we missing which we should be aware of?

As suggested by Castro-Caldas et al. (1998), learning to read and write adds a visuographic dimension, based on operation of matching phonemes and graphemes, to the internal representational system for spoken language, so learning a specific skill during childhood may partially determine the functional organization of the adult brain. _Can Literacy Change Brain Anatomy? Ostrosky-Solis 2004 IJP 39 (1) 27-35

Of course, since reading comprehension is part of what comprehensive IQ tests measure, pointing out that increased literacy rates leads to higher IQ scores is a somewhat tautological -- or circular -- argument. Nevertheless, the human brain is inherently circular in function, and the evidence for a significant change in brain structure due to the acquisition of reading and writing should not be dismissed.

As has been pointed out, the general spread of affluence (in the sense of increased food, education, information technologies, and leisure time) over the 20th century -- at least in the countries and over the time spans registering a significant Flynn Effect -- would lead to a cluster of changes in the pre-natal and post-natal environment of children. Better nutrition, a richer stimulatory environment, increased literacy, better prenatal and childhood medical care, increased exposure to music and music training, etc., could all lead to changes in brain structure and brain function in these upwardly evolving societies.

And yet, it is relatively easy to "cut to the chase" by looking at members of societies who are already at the top of the heap, the affluent socioeconomic classes. By looking at "pre-evolved," already affluent members of a given population group, one can anticipate what the maximum effects of any Flynn Effect are likely to be on a given population.

Rather than to tell you what the results of such studies have been, it might be better to allow you to cogitate on the matter first.

Over time, we are able to incorporate more factors of potential importance into our concepts of the foundations of human cognition. We are stymied by politically correct limitations on what can be studied and tested, but despite the ongoing corruption of science by political correctness, the underlying structures will be worked out piece by piece.