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What Neuroscientists Now Know About Your Intelligence

A The Eminents interview of Richard Haier

CBlue98, Flicker, CC 2.0
Source: CBlue98, Flicker, CC 2.0

Richard Haier is President-Elect of the International Society for Intelligence Research and as of January 1, will be Editor in Chief of the journal, Intelligence. He is Professor Emeritus in the School of Medicine at the University of California, Irvine, an expert on the use of brain imaging to study the neural basis of intelligence, and the author of the forthcoming book, The Neuroscience of Intelligence. His video course, The Intelligent Brain is avalaible through The Great Courses

In today's The Eminents interview, I spoe with Dr. Haier.

Nemko: First, is there consensus on what the word "intelligence” means?

Haier: Researchers typically define intelligence as a general ability common across a wide range of mental abilities. This is known as the g factor. It can be estimated from mental tests such as standardized IQ tests. Although other factors are involved, such tests are good predictors of academic and life success.

Nemko: Is there a recent research finding on intelligence you're most excited about?

Haier: In the last decade, a number of neuroscientists have been looking at whether brain characteristics correlate with intelligence. Just a few weeks ago, an important study was published in Nature Neuroscience that shows the tremendous progress that has been made. Using fMRI data from the Human Connectome Project, the Yale researchers found brain patterns so unique to a person and stable within that person that they acted like "brain fingerprints" Even more exciting, those brain fingerprints predicted intelligence test score. This is light years beyond the limitations of traditional psychometric studies.

Nemko: Does another recent finding also excite you a lot?

Haier: There are a number of DNA analyses combined with neuroimaging in twins that have completed intelligence testing. The findings are compelling that brain structures have genes in common with intelligence. Larger and larger data sets are being collected and this area is advancing rapidly. It’s another example of neuroscience approaches to questions about intelligence that go far beyond older controversies from the last century about the meaning of IQ scores.

Nemko: It's long been agreed that intelligence is affected both by genes and environment. Have we learned more about that in recent years?

Haier: There are now many large-sample studies of twins from around the world that show genes account for more individual variance than environment on intelligence tests. In fact, heritability estimates for intelligence increase with age — up to about 80% in adulthood. Environment clearly plays some role, and some environmental factors likely influence the expression of some genes — this is the study of epigenetics. Once specific genes related to intelligence are identified, even if they account for only tiny proportions of variance, epigenetic influences on those genes can be determined. This will be a daunting task but is an area of great interest to neuroscientists.

Nemko:  Can we improve our intelligence?

Haier:  Every few years, someone publishes a paper claiming a large increase in IQ after some intervention — We have seen this with the Mozart Effect, memory training, and video-game playing. None of these claims have survived independent replication. If there were any way to increase intelligence, I would be the first to buy it. But once we have a neuroscience understanding of intelligence, we might find ways to manipulate the cascade of neurochemical events from synapses to networks that cause individual differences in intelligence. Then, dramatic increases in intelligence could be possible. Wouldn’t that be exciting? Wouldn’t you take an IQ pill?

Marty Nemko's bio is in Wikipedia