What does neuroscience have to say about the educational value of lectures?
Not much, says pedagogist Ken Masters in a lively article just published in Medical Teacher: Nipping an education myth in the bud: Poh’s brain activity during lectures
Masters lays into an emerging slice of neurononsense. The claim is that neuroscientists have shown that, during lectures, students brain activity flatlines – and is even lower than during sleep. There’s a superficially-plausible graph that purports to prove this. Here’s an expert – the ‘class’ section represents lectures:
The implications of this chart are immediately apparent: in a lecture, the student’s brain is less active than at most other times, including during sleep… this is damning evidence against the lecture as a method of education.
Although first published less than three years ago, this chart has already been cited on various internet sites and blogs, Twitter trends (#altc2012), education conferences and in education journals (Lancaster 2013). It has also recently been shown at the Association of Medical Education (AMEE) Conference in Prague in 2013.
With this grounding, it is surely only a matter of time before it becomes de facto evidence in medical education journal articles arguing against the use of lectures in medical education.
In fact, however, the chart has nothing to say about lectures, and wasn’t intended to. It appeared in a paper by Poh et al (2010), A wearable sensor for unobtrusive, long-term assessment of electrodermal activity. The data
were from a single device attached to a single volunteer student (N=1). The focus of the original research was not on lectures, or any other educational aspect, but was on testing a new mobile device (“a novel, unobtrusive, non-stigmatizing, wrist-worn integrated sensor”) to measure the device’s suitability and accuracy against an FDA-approved device.
While the results are valid for the purpose of the original research, applying them to any generalizability in medical education would be irresponsible. In clinical research, this would be the equivalent of accepting or rejecting a drug after a single trial with a single patient, with no further medical information and with no control group.
And the graphs don’t show brain activity at all:
According to the education researchers (Mazur 2012 time 2:39; Lancaster 2013; Neve et al. 2013; van der Vleuten 2013), brain waves or brain activity is being measured. Unfortunately, this is incorrect. Poh et al. were not measuring brain activity; they were measuring Electrodermal Activity (EDA). The purpose was the “measurement of EDA during physical, cognitive, as well as emotional stressors”.
[...] there is a wide range of possible causes of fluctuations, including fear, anger, sexual arousal or any number of stressors. Although these data would be interesting to examine in more detail, they do not indicate brain activity, and any inference about the student’s attentiveness or cognitive participation compared to other activities cannot be made.
As Masters says, the value of lectures is debated and there may be good reasons to think that they’re an ineffective form of teaching, but an n=1 study of skin conductance isn’t one of them. So this is an important little paper. It reminds me of one of my first ever posts, about educational neurononsense in schools.
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