The authors of the paper seem to have misinterpreted why many cognitively healthy students take ritalin/adderall. It's not to make you smarter or more able to solve complex problems, it's to let you focus and cram on large workloads for far longer than you otherwise would be able to. Basically, quantity over quality.
A much better test would have been to give all the study participants some new material requiring multiple hours of study to memorize & learn, then give them a test. The knapsack problem is fine to test some measure of "intelligence", but a bad choice to simulate academics.
A much better test would have been to give all the study participants some new material requiring multiple hours of study to memorize & learn, then give them a test. The knapsack problem is fine to test some measure of "intelligence", but a bad choice to simulate academics.