Individual studies of the topic show different, and sometime contradictory, results, and as one meta study puts it, asking the question “Does cognitive training improve intelligence?” is as inappropriate as asking “Does medicine cure disease?”, since none of them specify which particular intervention (which medicine or working memory training program) is being evaluated, for alleviating which condition is it applied (ADHD, stroke, general cognitive improvement etc.), and under what circumstances is it administered (selection criteria, adherence rate, outcome variables etc.).