The short answer, of course, is an IQ test-But here are some facts about IQ that might surprise you from Psychology Today.

  • FACT 1: IQ is affected by school attendance. Although intelligence does influence the decision to stay in school, staying in school itself can elevate IQ. Or, more accurately, it'll prevent it from slipping. Each additional month a student remains in school will increase their IQ.
  • FACT 2: There is a correlation between IQ and head size. Modern neuroimaging techniques prove the link and there was also a study of members of the Armed Services. Those with the biggest helmet sizes were also the ones whose IQs were the highest.
  • FACT 3: Intelligence scores can also predict income. Generally speaking, the greater a person's IQ, the higher that person's weekly earnings.
  • FACT 4: IQs are on the rise. IQ has risen approximately 20 points with every generation. If people taking an IQ test today were scored against their grandparents' performances 50 years ago, more than 90% of them would be classified as "geniuses." But if our grandparents were scored today, most of them would be classed as "borderline mentally retarded." That's the term Psychology Today used, that's not my opinion. The rise in IQ has been attributed to factors such as better nutrition, more schooling, better-educated parents and more complex spatial environments thanks to smart toys and computers.