If that's the case, then fair point. But I've seen a lot of articles that talk about the ostensible benefits of simply having Mozart (etc.) on in the background

If that's the case, then fair point. But I've seen a lot of articles that talk about the ostensible benefits of simply having Mozart (etc.) on in the background. It was hard to get a sense of which approach this article was talking about when mentioning the subject. Passive/ambient listening may have some benefit to a small baby, whose brain is much more plastic and is generally responsive to interesting stimuli. But for adults, a more active and taxing activity is probably in order. I agree with you that the loci of improvement are probably concentration and recall.