Various adult learning theorists advocate self-direction. Adults want to chart their own paths and learn better if they do so. To me, the model seems very much like surfing the Internet: click here, click there, whatever interests you.
If you’ve done any online courses recently, you probably haven’t seen much that is designed this way. Online courses tend to be particularly linear—mostly devoid of learner choice. Why is that?
One answer is lack of trust. Designers have a goal and subject-matter experts think they know how to get there. They’ve never experience the road-not-taken. They devalue any learning experience that deviates from their preconceived notion. The problem is motivation. If I, as a learner, follow your path and not mine, I’m probably not very motivated. There are multiple paths to learning and we need to facilitate that as course designers.
Another answer is an assumption of efficiency. Designers are often under pressure to deliver the absolute minimal learning in the shortest amount of time. No digressions are possible. No failures, even if thoughtful reflection on a failure leads to superior learning in the end. This way of operating leads to learning that keeps students as dumb as possible for as long as possible. We want the gold, but we have no patience with processing the ore.