As of this writing, it has been 24 years since 1988 (man, you don’t know how old that makes me feel). You would think that would be enough time for us to figure out that filling slides with text doesn’t work.
Why 1988? That’s the year John Sweller formulated Cognitive Load Theory, a theory about how we learn things. It’s related to the work of Princeton’s George A. Miller in 1956 that suggests we can only retain around seven discrete items in short-term memory. Though CLT has a number of implications for learning, we’re concerned here with the insight that when we are presented with both a written and an “out loud” version of the same information, we ignore one or the other. In other words, we can’t listen and read at the same time. Continue reading