One potential application for our basic studies of skill learning is understanding the development of skill in performing surgery.  So I was intrigued when happening to stumble across the following report of factors predicting successful surgical outcomes:

Surgeon specialization and operative mortality in United States: retrospective analysis

BMJ 2016; 354 doi: http://dx.doi.org/10.1136/bmj.i3571 (Published 21 July 2016) Cite this as: BMJ 2016;354:i3571

http://www.bmj.com/content/354/bmj.i3571

The take home message was that ‘specialization’ may be as important as repetitions in successful skill performance.  The following clipped paragraph captures many of the things I find fascinating here:

At the same time, the degree to which a surgeon specializes in a specific procedure may be as important as the number of times that he or she performs it.11121314 A surgeon who specializes in one operation may have better outcomes owing to muscle memory built from repetition, higher attention and faster recall as a result of less switching between different procedures, and knowledge transfer of outcomes for the same procedure performed in different patients.815161718 If this specialization hypothesis holds true, a surgeon performing 20 procedures of which all 20 are valve replacements (denoting 100% specialization in the procedure) would have lower operative mortality rates than a surgeon who performs 100 operations of which 40 are valve replacements (denoting 40% specialization in the procedure). In contrast, the volume-outcomes hypothesis would suggest that selecting the surgeon who performs 40 valve replacements would lead to superior outcomes for patients. To the best of our knowledge, no study has described a statistical association between a surgeon’s degree of specialization in a specific procedure and patients’ mortality.

Of note, this is not what we’d expect from our lab work.  We find reps to be the most important.  Is there something we are missing in our work that captures some factor based on ‘specialization’?  Or is the study being influenced by other variables.

Note the assumption in the text that specialization leads to better “muscle memory.”  We think that should derive from reps, but have often wondered about interference.  Interference among procedures would produce a specialization effect, but we’ve never observed interference among sequences learned together.  Another possibility is something like “rust” — perhaps less specialized surgeons have longer intervals between performances (we have seen something like that in our forgetting curves).

It’s also possible that these ‘unspecialized’ surgeons are simply performing too many surgeries and having fatigue or other state effects.  You wouldn’t be able to spot those effects without the analysis done here because practice would be improving performance and hiding any costs of doing too many.

Or maybe it is something else entirely…