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Comment by jacobolus | Hacker News Reader

This seems to be a different thing than just practicing different activities related to the same sport. These are two functionally similar activities which use slightly different muscle patterns to accomplish, so that the trainee is directly applying their knowledge of the first action to the second, but can’t just do the precise same motion.

> “If you make the altered task too different, people do not get the gain we observed during reconsolidation. The modification between sessions needs to be subtle”

A better baseball analogy might be practicing catching line drives then practicing catching popups then practicing catching one-bounce throws then practicing catching a lobbed egg.

Or maybe practicing batting and then practicing golfing and then practicing kendo swings.

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If I'm reading the source article correctly (linked below by Perixoog), it sounds like change was so subtle that the participants themselves weren't even aware of it:

"Participants were unaware of this manipulation"

"We chose to manipulate sensorimotor variability so that participants were unaware of the fact that there was any change in the task"

[1] http://www.cell.com/cms/attachment/2045379445/2056784269/mmc...

So not only are the tasks similar, but they're so similar that participants weren't consciously aware that they were doing something different. Wacky

They also mention that "participants strengthened skill through the re-exploration of sensorimotor space."

I wonder how large an exploration of the sensorimotor space could be while generalizing/improving the original skill. (re batting and kendo). No idea, but interesting article either way

Which makes me wonder if you can apply this as an autodidact. If you know you have made subtle changes, do the results still hold. I'd guess the answer would be yes but it could be an interesting problem.

There also might be a delta (variation of the activity) that optimizes the learning progress. My guess for that would be...change too little and you're inefficient, change too much and you are inefficient, too.

This is all speculation, on my part (certainly not an expert in this area)

In the article they say that "Contextual variability can strengthen retention [15] and generalization of skills", but that they "chose to increase sensorimotor variability while maintaining constant the original learning context."

They also mention that "attributing errors to internal sources can strengthen learning [19, 20] and generalization [21] of motor behavior"

My guess for an autodidact would be how powerful internal attribution is compared to the change in context and exploration of the sensorimotor space. Of course, they're probably not discrete, and probably also impact one another.

Sounds like some really interesting possible implications, and possibilities for further research. Really makes me want to reread the article and go through some of the articles they cite

The delta factor is probably e!

> “If you make the altered task too different, people do not get the gain we observed during reconsolidation. The modification between sessions needs to be subtle”

I saw that quote but I have no idea what the researcher is basing it on. As described, the study can only show that blocking/interleaving is superior to massed practice:

> The volunteers were split into three groups, and each spent 45 minutes practising this. Six hours later, one of the groups was asked to repeat the same training exercise again, while another group performed a slightly different version that required different squeezing force to move the cursor. The third group only completed the first training session, so they could act as a control.

That is, as described, there is no 'interleaved subtle-difference' vs 'interleaved gross-difference' comparison, because they only compared 'near-zero-practice' vs 'massed-practice' vs 'interleaved-practice'. They seem to be wildly extrapolating from there, in ignorance of a good deal of prior work.

A tangentially-related point:

> practicing batting and then practicing golfing and then practicing kendo swings

Actually, as the subject progresses toward being an "expert" their practice should be increasingly specific. Beginners will certainly benefit from the approach you mention initially, but professionals will not.

Regular successful achievement of a physical task (reliably hitting a ball with a bat) can be considered a walk through a problem space. Initially, any training that approximates the task will take you closer to the target in the space. However as you approach that target, the margin for error diminishes sharply. Consequently your training should become more specific.

We got best improvement on our catcher by getting close enough to force a rapid response, or get hit by the ball, and a series of varied throws. High left, low right, center fast, high slow...

Take a bucket of balls and just run through them quick.

This seems to align with the study. Same basic task, lots of minor, well in our case occasionally major too, variations. The kids would improve notably and significantly in a single session.

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