Reflection on Roger Schank's 'Expectation Failure'. Schank suggests that learning is achieved through expectation failure. You have a mental model for how something works, then you encounter an event or data that breaks your mental model. You incorporate that new information and adjust your mental model. 

The strongest way to learn is to have a hypothesis and then act on it. For example, knowing how a saw works in your head and then actually using a saw to cut wood and realising it's rather hard to cut perfectly straight. 

A weaker version of expectation failure is encountering new information you were not looking for. For example, reading leisurely about France and learning that it was called Gaul in ancient times.

The implication is that the learning by doing is a far more effective way of learning than reading and absorbing facts. Unused facts dissipate from memory far more quickly.