Are We Becoming More Intelligent?

The Flynn Effect1 refers to the substantial and long-sustained increase in intelligence test scores that has occurred over the last one hundred years in the industrialized countries. The average score for an IQ test is 100. Periodically these tests are redone and renormed (that is the average is recomputed with a standard deviation of 15). When the scores of people taking the new test are compared against the scores of the same people taking the previous test, the scores are typically higher. One estimates is that an IQ of 80 today would equate to an IQ of 100 in 1932. How can this be? Are we becoming more intelligent? If we are becoming more intelligent this increase is occurring much more quickly than could be explained by genetic evolution.

According to Flynn, statistical estimates are that genes account for 36 percent of the IQ variance and that environmental and experiential factors account for the remaining 64 percent. The problem is that it is impossible to conduct a study where genetic and environmental factors are independently controlled. The reality is that there is an interaction between these two factors, and it is this interaction that explains the Flynn effect.

Flynn uses an analogy with basketball to make his point. Suppose a pair of identical twins genetically endowed to play basketball are separated at birth. Regardless of the different environments under which they are raised, they are both likely to play basketball and to practice assiduously. Consequently they will excel at basketball and eventually attract the attention of coaches who will further foster their talents and abilities. A similar interaction between genetic inheritance and environmental factors can be found with identical twins with high IQs who are raised in different environments. Regardless of their respective environments they are more likely to be drawn to learning and will perform better in school. They are more likely to be admitted to competitive universities where their IQs will be increased even more.

Flynn says, “There is a strong tendency for genetic advantage or disadvantage to get more and more matched to a corresponding environment.” Accordingly, the environment will always be the determining factor of whether or not a genetic predisposition gets expressed. This applies to all our cognitive powers, not just IQ. So we can increase our own cognitive powers by our own deliberate efforts. This calls to mind what Thomas Edison said about genius, that it was one percent inspiration and ninety-nine percent perspiration.

So the answer to the question, “Are We Becoming More Intelligent?”, the question to the answer is “What is Intelligence?” But we do have the ability to increase our cognitive powers throughout our lifetimes through our own deliberate efforts.

1Flynn, J.R. (2007). What Is Intelligence? Cambridge University Press.

© Douglas Griffith and, 2011. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and with appropriate and specific direction to the original content.


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