A grown-up man won't sit still in a classroom while a teacher drones on about subjects that don't interest him. Andragogy recognizes that adults demand to learn things that are relevant to them, and that leverage their own life experiences rather than assuming they know nothing. Adults don't want sweeping coverage of a topic; they want to learn the parts that are interesting or relevant to them now, so they tend to prefer problem-based learning that shows the immediate applicability of what they're learning.

If adults won't stand for sitting for hours, learning about things they don't find interesting or relevant, why is it that children do? And why should they? The common response to the second question is that children don't know what they need to learn, so they need educators to decide for them. To some degree this is true; however there's overwhelming evidence that all people learn better when they're interested in the topics, and there's similar evidence that there are correlations between what we enjoy doing, what we're good at, and what we'll end up doing professionally. Typically, though, we don't teach children what fits their interests, motivations or natural talents. We simply use a one-size-fits-nobody technique that enables us to teach each student in a class of 25 almost equally poorly.