These three drugs may boost your thinking skills but cost you time-wise

In chess players, cognitive enhancement agents boosted performance marginally -- but not if speed was a factor.
(Koen Suyk / AFP/Getty)
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For the cognitively ambitious among us, there are always new debates to win, tests to ace, and feats of intellect to accomplish. And just as for the athletically gifted, the lure of performance-enhancing drugs is hard to resist.

The question is, can drugs boost intellectual performance?

For the record:

5:32 a.m. July 22, 2024An earlier version of this article said some recruits were given 200 mg of Ritalin. They were given 20 mg.

New research shows that for tournament-level chess players, they can. In a series of experiments, researchers found that caffeine, the stimulant Ritalin and the stay-awake drug modafinil ever-so-slightly improved players’ chances of winning a game against a computer program set to their skill level.

In a single game, the edge gained by taking one of these cognitive enhancement drugs was subtle — essentially, the equivalent of giving a player the opening move. But over many chess games, the marginal improvement seen in players taking Ritalin (whose generic name is methylphenidate) and modafinil could propel a player’s ranking upward from 5,000 in the world to nearly 3,500, the authors reckoned.


“The enhancement effects of methylphenidate and modafinil … are large and relevant,” write the study’s authors, led by psychologists Andreas G. Franke and Klaus Lieb at the University of Mainz in Germany.

But that improvement came with an important caveat: Players under the influence of performance enhancers slowed their play enough that when chess games were conducted under tight time pressure, they were more likely to lose a game because of poor time management.

In short, for these cognitively enhanced competitors, greater prowess came with more deliberation. And more deliberation came at the cost of speed. There’s no free lunch here.

The new study, published this week in the journal European Neuropsychopharmacology, set out to rigorously test whether three drugs with reputed powers of cognitive enhancement actually improved users’ performance of complex, real-world intellectual tasks more than a placebo. They recruited 40 German chess players between the age of 18 and 60 who were skilled enough to be tournament-ranked.

Over at least a month, researchers had each participant come to the lab on four separate days. After breakfast and again after lunch, each recruit was given either 200 mg of caffeine, 20 mg of Ritalin, 200 mg of modafinil (marketed as Provigil), or a placebo. All were packaged identically in capsule form.

On each of four days, every participant underwent neurocognitive tests and played a total of 20 games of chess against a computer program. By the end of four sessions, each player had tried each of the four agents.


Competing against the chess program at the level on which one is tournament-ranked, an un-enhanced human player should prevail 50% of the time. Sure enough, under the influence of placebo, players won 51% of the time.

Over 757 games played under the influence of Ritalin, players won 54.1% of the games. Hopped up on caffeine, players triumphed in 54.3% of 760 games. In 763 games, modafinil boosted players’ win rates to 55.1%. Overall, that’s an performance improvement of 6% to 8% over the placebo.

As for the speed issue, compared with players on the placebo, the players’ average reflection time per game increased when they were administered a capsule of caffeine, Ritalin or modafinil. Over all players, average reflection time per game rose from 437 seconds for those on the placebo to as high as 553 seconds for those on modafinil.

Compared with players taking a placebo, those taking any one of the three cognitive enhancement drugs were much more likely to lose a game on time or due to time trouble. When the researchers stripped out games lost on time, players who got modafinil and Ritalin (but not those on caffeine) showed even greater performance enhancement over those on the placebo.

When the researchers looked at players’ performance on standard tests of cognition, it was difficult to discern any differences that might have been attributable to the drugs they took. Players’ performances on tests gauging processing speed, fatigue, visual attention, cognitive flexibility and risk-taking didn’t vary significantly depending on what drug they took. Only when players took Ritalin, widely used to treat attention deficit hyperactivity disorder, did they show an enhanced ability to tune out distractions.

The study’s findings certainly have implications for chess competitions. The World Chess Federation has adopted the World Anti-Doping Agency’s list of banned substances, including Ritalin and modafinil, but not caffeine. The fact that neither body sees a problem with caffeine “is questioned by our data,” the authors wrote.


For the performance of complex and highly demanding intellectual tasks, the study suggests that cognitive enhancement is a real possibility. If time is not a factor, taking any one of these three drugs appears to significantly improve an individual’s ability to sort through competing strategies, tune out distractions and deliver an improved performance.

But when time is limited — especially for people who tend to be slow and deliberative to begin with — that improved performance may come at too high a cost.



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