Not so smart? "Smart" drugs increase the level but decrease the quality of cognitive effort.
Level 2 - randomized trial
Placebo-controlled trial evaluating pharmacological cognitive enhancers
PubMed 37315143 · doi:10.1126/sciadv.add4165
What was done
Participants completed a complex computational decision task (the knapsack optimization problem) under the influence of methylphenidate, dextroamphetamine, modafinil, or placebo to assess the effects of cognitive enhancers on task performance, decision time, and solution strategies.
What was found
Methylphenidate, dextroamphetamine, and modafinil significantly reduced the knapsack value attained compared to placebo, although the chance of finding the optimal solution (~50%) did not change significantly. Effort (measured by decision time and number of steps taken) increased significantly, but productivity (quality of effort) decreased significantly. Baseline differences across participants reversed, with above-average performers dropping below average due to increased randomness in their search strategies. No exact sample size or effect sizes were reported in the abstract.
Why it matters
These results challenge the assumption that smart drugs improve performance on complex everyday tasks, demonstrating that higher motivation and effort can be offset by poorer strategy execution.
Limits
The abstract omits sample size, participant characteristics, exact drug doses, and numerical effect sizes with confidence intervals. The stylized knapsack task may not capture all aspects of real-world decision-making.
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