Surprise is a trigger for learning, so deliberately tap into learners' curiosity.
Would you be surprised to learn that suprise is the core driver of learning? Would that suprise drive you to learn more about surprise?
Much of the latest cognitive science research is too esoteric to have an impact on instructional designers' daily work; however, recent theorizing suggests that people learn as an effort to minimize future surprise. On the other hand, surprise is an eagerly pursued form of