IQ Tests and Exceptions to The Rule

For most individuals, intelligence Quotient (IQ) tests have relatively high predictive validity. Scores are also likely to remain consistent across the lifetime of individuals. However, as with medical tests, there are always patients that display exceptions to this general rule.

At age 6, I displayed a 40 point discrepancy between my verbal and performance IQ on the WISC (Wechsler Intelligence Scale for Children). with my verbal IQ in the high average range and my performance IQ in the borderline range. When retested at age 12, my performance IQ was in the average range and my verbal IQ was in the superior range. Sometimes, children with learning disabilities are able to use their areas of strength to compensate for their weaknesses. For instance, I learned to verbalize my way through visual-spatial tasks. The psychologist administering the test noted that I spoke aloud to myself as I solved the non-verbal portions of the test.

The high predictive validity of IQ tests still stands for the general population. However, predicting an individual's future (especially when making decisions that will have a major impact such as choosing to place a child in a special education class) should be done with extreme caution. In addition to cases with children with learning disabilities, there is also some controversy about IQ testing with children who are recent immigrants or who have low socioeconomic status. For instance, a child may do poorly on the verbal section of a test due to lack of general knowledge about Canadian culture or a language barrier rather than a learning difficulty.

Except in the case where cognitive disability is fairly certain, limiting a child's educational opportunities by placing them in an educational program that will not give them full access to academics may put an artificial cap on the potential of the child. In some cases, a child will simply need accommodations such as extra time to complete tasks and additional instruction in order to perform at grade level. In other instances, modifications to the child's home environment can make a difference. Modifications to the core outcomes of the academic curriculum should be a last resort.

The best use of an IQ test with children with disabilities or other barriers to learning such as poverty is to determine their current strengths and weaknesses so professionals can best determine ways to help children overcome or compensate for these difficulties. As a child, my parents and therapists spent time coaching me in how to use self-talk to convert visual information into words. That and my already strong verbal skills allowed progress much farther than predicted in visual-spatial abilities. I was even able to interpret curves in first year University calculus with the help of a tutor. However, as predicted by that initial test at age six, residual difficulties still remain. For instance, I have problems with direction and orientation in space, thus taking many trials before I learn a route. The intent of this post is not to discount the predictive validity of IQ tests, but rather to state that humans are a diverse population and that not every individual in this population will perform as predicted. Therefore efforts should be made to aim for the best possible outcome rather than the predicted outcome.