A persistent error is a sign that learning has occurred, but the student has inadvertently learned the “wrong” way really, really well and needs to unlearn it:
Researchers at the University of Verona (Milanese et al., 2008) conducted a study of thirty 13-yr olds learning how to perform the standing long jump in three sessions spread out over a three week period.
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One group received instruction using an experimental teaching method called “Method of Amplification of Error” (MAE group). More details on this in a moment, but the tl;dr version is that this method involves doing things wrong on purpose, not just doing things correctly.
Another group received the traditional instructional method of verbal instruction (direct instruction group).
And the third group received no instructions at all, and just practiced on their own (control group).
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The kids who received no instructions at all performed pretty much the same at both tests. They jumped 158.9cm on the first day of training and 160.6cm on the final day of training. A difference which isn’t statistically significant, and is pretty much what you’d expect.
On the other hand, the students who received instruction and feedback during training did improve over the course of three weeks. They started out at 159.4cm, and improved to 162.3cm by the final test – a gain of 2.9cm. And though an improvement of just over an inch may not sound like much, this would have been the difference between medaling and not medaling in the men’s long jump at the 2020 Tokyo Olympics.
And how did the amplification of error group do?
Well, the kids who were coached using the Method of Amplification of Error improved by an average of 20.4cm, going from 159.5cm on the first day of training to 179.9cm three weeks later. This is almost 7 times the improvement of the regular instruction group, and would have been the difference between Gold and Bronze at the same 2020 Olympics. In the same exact amount of training time!
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On the surface, the Method of Amplification of Error training was not hugely different. The only difference was that instead of being instructed to jump with the correct technique, they were told to exaggerate as much as possible the main error that the instructor identified.
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It seems pretty counterintuitive to practice doing something the exact wrong way, but the researchers explain that this actually deepens our understanding of what not to do and initiates an internal search for a better way to perform the skill.
Nothing improves performance like no witnesses. I don’t suppose that the researchers had a video camera either.