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Earl Hunt Ph.D.

Earl Hunt Ph.D.

Improving Intelligence

How can we improve intelligence and how do we know if a method works?

This is a summary of a longer essay. Anyone interested in the complete essay can email me at and I will be glad to send a copy.

Americans want sharp minds and flat abs. The internet, magazines, and TV abound with advertisements offering ways to sculpt your mind and chisel your body. Or is it the other way around? Whatever … there is a remarkable analogy between programs trumpeted to improve intelligence and to improve physique. What is going on?

Many of the claims assert that they are revolutionary, because intelligence researchers, or psychologists, or somebody, has said that you can’t improve your intelligence, In fact, no respectable intelligence researcher has said that problem-solving abilities cannot be improved. They have said that you have a genetically established potential for intelligence, and that the environment determines the extent to which you realize that potential. Intelligence researchers have also said that your intelligence test score, which indicates your relative standing in the population, is pretty stable once you reach early teenage years. There are certainly changes in cognitive power over the life span. A 70-year-old can solve a lot more problems than an 11-year-old can. The relative ordering of people at 70, though, is surprisingly similar, though not identical, to the relative ordering at 11.

Athletic ability can be improved by practicing relevant skills (such as keeping your eye on the ball), exercising to build up muscles (push-ups anyone?), and by using bodybuilding substances, which can range from a Mediterranean diet (red wine with fish) to steroids. Attempts to improve intelligence are similar. You can become smarter by acquiring useful, widely applicable cognitive skills, such as logical reasoning, critical thinking or mathematics. That’s like learning to keep your eye on the ball. Learning these skills is equivalent to becoming educated. You can also take the mental pushup approach; practice tasks that exercise the neural pathways central to cognition. The brain … even the adult brain … is surprisingly plastic. Using a circuit will improve the efficiency of transmission along the circuit, probably by strengthening the relevant synaptic connections. The “new” mental exercise programs are designed to exercise the working memory and control of attention circuits in the brain, because working memory and the control of attention have been shown to be a key component of general intelligence. Finally, there are both pharmacological and neuropathic agents that will make temporary improvements in cognition. These change either the supply of neurotransmitting chemicals in the brain or the brain’s sensitivity to them.

Education clearly works. It’s been estimated that every year of education adds from two to three points to a student’s IQ. Kids, pay attention in school. Senior citizens, head for the community college! It is important to learn both the thinking skills and the circumstances under which those skills are useful. This is one of my gripes with education, from roughly high school through graduate school. Educators too often stress how to execute thinking skills without explaining when to execute them.

Most of the programs marketed to improve intelligence resemble mental calisthenics and brain pills more than education. The tasks are not great new discoveries, in spite of what the advertisements say. The most popular task, the N-back task, “exercises” the brain circuits underlying working memory and the control of attention. This has been a staple in cognitive psychology laboratories for almost 40 years. Exercise using it and you will improve intelligence? Maybe, but warning—I’ve done the N-back task and I’ve done push-ups. Push-ups are more exciting. Eat this diet, or take Yakov’s elixir, and your neurons will work better? Various forms of ‘brain pills’ have been around for a long time. One of the most popular nutritional additives, ginkgo balboa, has been a staple of Asian medicine for hundreds of years.

How should you evaluate claims to improve intelligence? I offer these guidelines.

1. Beware of testimonials. Any advertiser can find (three out of five doctors) (an actor who looks like a doctor) (a pretty young woman) (a gracefully graying senior citizen) to go on TV and say, “I was a dolt, I took this course (or took this pill) and now I am the reincarnation of Einstein.” Well, maybe they won’t put it that strongly, but you get my idea.

2. Look for reports of randomized controlled studies, sponsored by a reputable body, such as the National Institute of Health (NIH), National Science Foundation (NSF) or a well-known university. Research by a wonderfully named foundation that you never heard of is suspect. The National Institute of Health has useful public information web pages discussing pharmaceuticals and nutritional additives.

3. Ask how big the effect is, and who benefits from it. Many treatments have their greatest effects upon moderately poor cognitive performance. Very bad performance may indicate brain damage that requires great efforts to overcome. If performance is already in the good range there is a general law of diminishing effects; the better you are before treatment, the harder it is to improve performance. This rule applies to mental exercise, brain food, and brain pills.

4. Educational effects can last for years. Mental exercise and various sorts of brain food will have temporary effects. (Just as you don’t stay fit forever after you stop exercising!) The effects do not stop at once but they will fade.

5. Long-term improvement requires a long term effort. Weight lifting for one day won’t do much for your body. Practicing the N-back task for one day won’t do much for your brain. Just as it takes discipline to keep up a weight lifting regimen, it takes discipline to keep up a mental exercise program. As for the pills approach, be sure to read the NIH informational website for discussions of any long term effects.

6. Improving intelligence should have widespread effects. Any claim that relies on just one test is suspect, for the effect may be on the special cognitive skills required on that test rather than on intelligence in general. In fact, the best evidence is probably not that performance on an intelligence test has been improved. The best evidence is that people who do these exercises or take these substances show improved cognition in their daily life. Unfortunately, such evidence is hard to get, so instead we rely on “intelligence tests.” These evaluate some important cognitive skills, but not all of them.