I.Q. tests are traditionally viewed as a quantitative measure of a person’s intelligence. Children who score very well on I.Q. tests are often tracked into programs for the “gifted,” while those who do very poorly are tracked into “remedial” programs. Despite their prevalence, the true meaning and import of I.Q. tests are subjects of some controversy in the fields of education, psychology, and neuroscience.

Over the past year, the subjects of intelligence, a possible biological basis for intelligence, and ways to improve intelligence have all received a significant amount of media attention. This article is a short review of some of these studies.

There seem to be two main camps on the subject of intelligence. In one camp are the researchers who not only support the concept of I.Q. as a measure of intelligence, but also believe that there is a biological switch that governs this intelligence, such as a gene or some kind of brain chemical. These researchers also believe that I.Q., and thus intelligence, can be improved by external means, such as through dietary supplements or specific learning exercises.

In the second camp are the researchers who reject the concept of a single definition of intelligence and suggest instead that human intelligence is too complex a mesh of qualities which cannot be measured by a single score on a single test. These researchers also believe that intelligence can be improved, but only by incorporating a much wider definition of intelligence than is currently in place in our society.

Let’s start with some of the studies that fall into the first camp of opinion on I.Q as a measure of intelligence.

In July 1999, researchers at the University of New Mexico announced a study linking levels of two brain chemicals to performance on I.Q. tests.

William Brooks and his colleagues used brain-imaging techniques to measure levels of choline and N-acetylasparate (NAA) in the brains of 26 healthy volunteers.

The researchers found that people with low levels of choline and high levels of NAA tended to have the higher scores on I.Q. tests. The researchers suggested that a manipulation of the levels of these brain chemicals, such as with dietary supplements, could increase I.Q. scores.

Methods for increasing I.Q. scores abound in the press and are also the focus of a number of academic articles.

The well discussed and much publicized “Mozart effect” stems from a Wisconsin study that suggests that listening to Mozart boosts IQ. Although a number of later studies suggest that the effect may not be as powerful as originally thought, many preschools have instituted programs such as “Mozart hour” to give their students the music’s perceived benefits.

Popular dietary supplements such as gingko biloba and phosphatidylserine are advertised as brain enhancement products that improve mental functions such as problem solving and memory, although there is very little scientific evidence to support these claims. There is even a firm out of Beverly Hills that offers a product called “Brain Gum”. Their promise for the product is encapsulated in their phone number: 1-888 “IQ BOOST”.

In the field of child development, Linda Acredolo, a psychology professor at the University of California, Davis, has found that babies who are taught sign language starting at the age of 11 months tend to have higher average IQs when they reach second grade than their peers who were not taught sign language (scores were 114 for the sign language proficient, 102 for the non-signers).

Behavioral experimentation on mice is a traditional tool for the study of gene manipulation on intelligence. Last September, researchers at Princeton reported that genetically engineered mice that over-express a particular form of the brain protein called the NMDA receptor perform better at a number of behavioral tasks than normal mice. The researchers suggest that this receptor could be a target for treating learning and memory disorders-this creation of a mouse that performs well on memory tasks has been described as a possible first step in making human beings “smarter”.

One question should be considered: Does performance on I.Q. tests really tell us something concrete about a person’s intelligence? This leads us to the second camp of researchers-those who argue that traditional I.Q. tests do not tell the whole story.

Howard Gardner, a professor of education at Harvard University, proposes the theory of “multiple intelligences” in which there are at least eight different types of intelligence, all of which must be taken into account when establishing a vision of a person’s abilities and potential.

Michael Howe, a psychology professor at Exeter University, has spent ten years studying the development of high achievers, such as Mozart, Michael Faraday and Isaac Newton. In his book Genius Explained, Howe argues that most “geniuses” don’t have some ineffable quality that promotes their intelligence above that of the general population. He argues that what distinguished these admittedly remarkable people was incredible persistence and devotion to their particular field of interest. Howe believes that sheer intelligence as measured by an I.Q. test won’t automatically lead to success without the added qualities of determination and perseverance.

Another researcher, Dr. Ken Richardson, also argues that the idea of an I.Q. score is too strict of a limit on the definition of intelligence. In his book The Making of Intelligence he suggests that the idea of a single cause or kind of intelligence is not supported by our ever-increasing understanding of the mind and its functions. His main idea is that intelligence is not a static thing that is coded for us by our genes, but is instead a result of a dynamic interaction between the mental process with which we represent the world and the culture in which we live. According to Dr. Richardson, society has as much an influence on our intelligence as do our genes.

Thomas Edison’s famous definition of genius as 99% perspiration and 1% inspiration suggests that intelligence is as much a product of nurture as it is of nature. However, it is the question of the origin of that mysterious 1% that fuels much of the interest in I.Q. scores, memory enhancing drugs, and mind-boosting music. Research results from the “smart mouse” and from the New Mexico study on brain chemical levels suggest that there may in fact be a biological quality, be it gene or chemical, that is the seat of that extra brain power that details the difference between “smart” and “not-smart”, “gifted” and “remedial”. Researchers like Gardner and Richardson argue instead that the brain is too plastic and complex for intelligence to be limited by the actions of a single gene, chemical or concept of I.Q..

All of this intriguing research tells us that, just as in so many areas of science, more time and study is necessary before we can hope to find a clear answer. In the end, the final answer to the question of intelligence will most likely be a multi-layered vision of human potential that combines all of these studies in biology, psychology and cultural context.

Linda Acredolo and Susan Goodwyn. Baby Signs: How to Talk with Your Baby before Your Baby can Talk. 1999.

Howard Gardner. Frames of the Mind: The Theory of Multiple Intelligences. 1983.

Howard Gardner. Intelligence Reframed: Multiple Intelligences for the Twenty-First Century. 1999.

Michael Howe. Genius Explained. 1999.

Ken Richardson. The Making of Intelligence. 1999.

Tang et al. “Genetic enhancement of learning and memory in mice,” Nature. September 2, 1999.