Why is teaching the best way to learn ?

For a new study in Applied Cognitive Psychology researchers led by Aloysius Wei Lun Koh set out to test their theory that teaching improves the teacher’s learning because it compels the teacher to retrieve what they’ve previously studied. In other words, they believe the learning benefit of teaching is simply another manifestation of the well-known “testing effect” – the way that bringing to mind what we’ve previously studied leads to deeper and longer-lasting acquisition of that information than more time spent passively re-studying.

The researchers recruited 124 students and asked them spend ten minutes studying a text, with accompanying figures, about the Doppler Effect and soundwaves – a topic about which none of them had any previous knowledge – with a view to teaching the material themselves afterwards without notes. Participants were told they could take notes while studying but not keep them for the next stage.

After the study phase, the participants were divided into four groups. In one group participants spent five minutes being filmed alone while they stood and delivered a lesson on the study material without notes (they could use a blank flip chart to draw figures if they wanted). The other groups either spent the same time completing multiplication arithmetic; standing up and teaching verbatim from a set script (including making reference to pre-drawn figures on a white board); or writing down all they could remember from the text (i.e. a form of retrieval practice designed to induce the testing effect).

A week later, all the participants returned to the lab for a surprise test of their knowledge and comprehension of the original study text in the form of six free-response questions that required them to explain key concepts from the study materials.

The critical finding is that the teaching-without-notes group outperformed the group that had spent the same time completing arithmetic problems and the group that had taught from a script, but so too did the group who simply spent the same time retrieving what they’d learned. In fact, the final comprehension performance of the teaching-without-notes group and the retrieval-practice group was comparable.

The researchers said their results suggest that “the benefits of the learning-by-teaching strategy are attributable to retrieval practice; that is, the robust learning-by-teaching strategy works but only when the teaching involves retrieving the taught materials.”