Engaging lecturers can breed overconfidence

Eloquent and engaging scientific communicators in the mould of physicist Brian Cox make learning seem fun and easy. So much so that a new study says they risk breeding overconfidence. When a presenter is seen to handle complicated information effortlessly, students sense wrongly that they too have acquired a firm grasp of the material.

Shana Carpenter and her colleagues showed 42 undergrad students a one-minute video of a science lecture about calico cats. Half of them saw a version in which the female lecturer was confident, eloquent, made eye-contact and gestured with her hands. The other students saw a version in which the same lecturer communicated the same facts, but did so in a fumbling style, frequently checking her notes, making little eye contact and few gestures.

After watching the video, the students rated how well they thought they'd do on a test of its content ten minutes later. The students who'd seen the smooth lecturer thought they would do much better than did the students who saw the awkward lecturer, consistent with the idea that a fluent speaker breeds confidence. In fact, both groups of students fared equally well in the test. In the case of the students in the fluent lecturer condition, this wasn't as good as they'd predicted. Their greater confidence was misplaced.

A second study was similar – 70 students watched either a fluent or fumbling lecturer, but this time the students had a chance afterwards to spend as long as they wanted reviewing the script. On average, both groups of students devoted the same amount of time (perhaps out of habit). But only among the students who'd watched the fumbling lecturer was there a link between time spent on the script and subsequent performance on the test. This suggests only they used the time with the script to fill in blanks in their knowledge.

"Learning from someone else – whether it is a teacher, a peer, a tutor, or a parent – may create a kind of 'social metacognition'," the researchers said, "in which judgments are made based on the fluency with which someone else seems to be processing information. The question students should ask themselves is not whether it seemed clear when someone else explained it. The question is, 'can I explain it clearly?'".

An obvious limitation of the study is the brevity of the science lecture and the fact it was on video. It remains to be seen whether this result would replicate in a more realistic situation after a longer lecture. Also, in real life, there may be costs to a fumbling lecture style that weren't picked up in this study, such as students mind wandering and skipping class.

Further reading

Carpenter, S., Wilford, M., Kornell, N., and Mullaney, K. (2013). Appearances can be deceiving: instructor fluency increases perceptions of learning without increasing actual learning. Psychonomic Bulletin and Review DOI: 10.3758/s13423-013-0442-z