Also, IQ tests become less accurate in the outer deviations. Just about impossible to test for a difference between 140 to 150 IQ, or 60 to 70. How much sleep a

Also, IQ tests become less accurate in the outer deviations. Just about impossible to test for a difference between 140 to 150 IQ, or 60 to 70. How much sleep a person got and their diet can change a brain's plasticity by more than that number of points. IQ tests aren't a great measure of plasticity in the first place - they're just the best thing we have to measure on a wide scale. Plasticity is a far more personal attribute. Many IQ tests just repeat the same problems, and a person can improve their score without really learning anything but how to take an IQ test. Throw someone something entirely new and you may get real insight into their mental plasticity.