"The mental ability of teenagers can improve or decline on a far greater scale than previously thought, according to new research. Until now the assumption has been that intellectual capacity, as measured by IQ, stays quite static during life. But tests conducted on teenagers at an average age of 14 and then repeated when their average age was nearly 18 found improvements – and deterioration." Big deal, my IQ fluctuates pretty much every day. Although that is probably related to alcohol.