Is there a Minimum Effective Dose for learning maths?

This is something I’ve been pondering a while, ever since I read about the concept in Tim Ferris‘ Four Hour Body:

“The minimum effective dose (MED) is defined simply: the smallest dose that will produce a desired outcome. Jones referred to this critical point as the “minimum effective load,” as he was concerned exclusively with weight-bearing exercise, but we will look at precise “dosing” of both exercise and anything you ingest.* Anything beyond the MED is wasteful. To boil water, the MED is 212°F (100°C) at standard air pressure. Boiled is boiled. Higher temperatures will not make it “more boiled.” Higher temperatures just consume more resources that could be used for something else more productive.

If you need 15 minutes in the sun to trigger a melanin response, 15 minutes is your MED for tanning. More than 15 minutes is redundant and will just result in burning and a forced break from the beach. During this forced break from the beach, let’s assume one week, someone else who heeded his natural 15-minute MED will be able to fit in four more tanning sessions. He is four shades darker, whereas you have returned to your pale pre-beach self. Sad little manatee. In biological systems, exceeding your MED can freeze progress for weeks, even months.”

Whilst listening to the recent interview with Kris Boulton on the Craig Barton podcast, they briefly talked about “Overlearning” in the context of repeating too many of the same question. I suspect we are thinking about similar things.

Is there an MED for students learning a particular concept and how would it vary from student to student? Would settling on an average MED for a class put some/many at a disadvantage compared to overlearning, which errs on the side of caution, ensuring that everyone gets more than enough, even if it is far from optimal for the majority.

Kris also mentions Variation Theory, which if applied correctly within the Direct Instruction model, probably negates the need to think in terms of an MED as the questions posed to the students are constantly changing. I need to look into this in more detail.

One technique I’ve used consistently in my years of teaching is the “Quick 5”, an idea given to me by Geoff Hannan. I attended a two-day workshop on Improving Boys’ Performance and the Quick 5 was the best take-away from the course. It was promoted as a way of keeping boys’ attention and keeping the pace of lessons swift. I have used it to great effect in many situations so maybe it is the mathematical equivalent of the MED.

I’d love to hear from you if you have any thoughts on what an MED for maths might look like.