Flynn observed changes in scores for intelligence quotient (IQ) tests over time. This has a number of implications on how IQ tests are designed and interpreted.


The Flynn effect is an increase in IQ scores over time when people take old IQ tests graded by the original guidelines.


Possible explanations:

(1) People are becoming more intelligent (which is unlikely).

(2) Performance on IQ tests are affected by education and other factors, so that the tests are imperfect measures of intelligence (whoops).


When an IQ test is initially released, it is adjusted to the population at that time, with the median given a score of 100. These adjustments may not apply to a different population.



(1) Performance on IQ tests taken over time must be interpreted with caution.

(2) IQ tests must be periodically recalibrated to the current population.

(3) Performance on an old IQ test taken today may be biased if the old grading standards are used.


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