Is intelligence fixed, or can it be improved over time? The answer, it seems, depends both on your age and how one defines "intelligence," a professor of clinical psychiatry explains in an op-ed for the New York Times.
Richard Friedman, director of the psychopharmacology clinic at Weill Cornell Medical College, says finding ways to stave off cognitive decline has personal significance to him.
Friedman—age 59—writes that "starting at age 55, our hippocampus, a brain region critical to memory, shrinks 1% to 2% every year, to say nothing of the fact that one in nine people age 65 and older has Alzheimer's disease." It is not surprising, he says, that a burgeoning brain-training industry has developed based on the idea that with a little work people can slow these declines—or even make themselves smarter than they were to begin with.
Study: Personality, not intelligence, predicts academic success
But what does the science say?
Cognitive enhancement is both "seductive and plausible," Friedman says. Our brains have a property called neuroplasticity, which allows them to remodel themselves and adapt in response to various stimuli. Brain training, the theory goes, prompts the brain to remodel itself in a way that increases cognitive function.
In one study of more than 11,000 people, researchers from BBC and Cambridge University put viewers of a popular online science program through six weeks of brain training. Participants were sorted into three training regimens in which they practiced for 10 minutes, three times a week:
- One group played games of reasoning and took tests of problem-solving skills;
- Another emphasized tests of attention, short-term memory, and math skills; and
- A third was the control group "that performed the equivalent of Google searches by answering obscure test questions," Friedman writes.
Researchers administered a modified IQ test at the beginning and end of the experiment.
Overall, "there was no evidence that brain training made people smarter," Friedman says. But participants over the age of 60 did show improved verbal reasoning skills after six weeks. A follow-up study that Friedman says will be published soon found continued training helped those participants maintain their improved cognitive skills over time.
Some critics might argue the results show a slowed decline in verbal reasoning skills—rather than enhanced cognition—but Friedman counters, "Call it what you will, but it still sounds fine to me."
Perception of one's own intelligence
On the lower end of the age spectrum, Friedman says other research suggests young people's perception of intelligence can have a significant effect on learning. In one study of low-achieving seventh graders, students who were told "to think of their own cognitive capacity as a quality that they can improve" scored significantly better on a test of material they learned in a summer seminar than a control group.
See also: Fields where a belief in innate talent dominates are less diverse
"Perhaps it is not the same as increasing innate intelligence, but helping young people hit their intellectual potential is critically valuable—and apparently not so difficult to do," Friedman says.
And what about those of us who are not especially young or old? Friedman says there is evidence that various types of exercise can improve memory and reduce brain shrinkage. While the mechanism isn't entirely clear, Friedman explains that exercise increases the level of a protein called brain-derived neurotrophic factor (BDNF), which is linked with the growth new neurons.
Low levels of BDNF in depressed individuals could be at the root of diseases' negative cognitive effects, he says.
How walking meetings make you smarter—and how to do them right
And finally, there is the question of drugs that improve cognitive performance like Adderall. Overall, Friedman says, "The only consistent cognitive benefit of stimulants is their effect on the consolidation of long-term memory, meaning that they strengthen the ability to recall previously learned information."
So, while stimulants may increase focus and some types of learning," there is no evidence that any prescription drug or supplement or smart drink is going to raise your IQ," Friedman concludes (Friedman, New York Times, 10/23).
Next in Today's Briefing
Why one expert changed his mind on student success software