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Desirable Difficulties

Psychologists Elizabeth and Robert Bjork, directors of the Bjork Learning and Forgetting Lab at UCLA, have invested decades of research in understanding how people learn new things, and how we forget them.  Their research has pointed to a number of ways we can enhance learning and practice that improve retention and performance.  They have coined the term “desirable difficulties” to describe factors we can introduce into our training sessions that help our long-term learning by making things more challenging for us in the moment.  These difficulties may slow our apparent progress in the short-term, but paradoxically, improve long-term performance and retention.  Hence the term desirable difficulties.



The Bjorks’ refer to the first of these difficulties as “variation,” which simply means changing up the conditions in which we practice.  This variation adds a measure of difficulty that may somewhat delay short-term performance gains but will produce better long-term skill development and retention.  For example, if we only practice landings on the same runway at our home airport, our landings may appear to get better faster, but our next landing at a different airport may not be as pretty.  If we practice landings at a variety of airports throughout our training, our short-term performance may appear to lag, but we’re building better long-term skills that will help all our future landings anywhere.  Variation helps us develop a skill independent of the conditions under which we perform the skill.

Variation helps us develop a skill independent of the conditions under which we perform the skill.

It’s important to vary the conditions of a skill, but not necessarily the skill itself.  For example, when learning the response to a simulated engine failure, practice the procedure the same way each time.  Introduce variation by simulating engine failures during different phases of flight, altitudes, locations, times of day, under the hood, etc.   Similarly, you could fly different airplanes of same make and model.  The variation comes from the different avionics and handling quirks unique to each airplane even though the skills practiced are the same.


Stick and Rudder

One area that could benefit greatly from variation are stick and rudder skills.  Pilots spend so little time outside of straight and level 1G flight.  Practice slow flight and stall recoveries at a variety of airspeeds, bank angles, attitudes, and G-loading (with an instructor until you’re proficient).  The reason turning stall recoveries are so uncomfortable for many pilots is due to lack of exposure.  Introducing stalls in straight and level flight is fine, of course, but most loss-of-control (LOC) accidents involve turns and/or higher than normal G-loads.  Students may learn straight and level stalls quickly in training (short-term performance), but it’s not preparing them for actual stalls encountered in the real world (long-term performance).  Variation can help improve that balance.  Desirable difficulties introduced in training can make for better life-long skills.  Afterall isn’t that the ultimate goal of training?

Stay tuned for more articles on getting the most out of training as we explore ideas from the Bjorks and other learning and development researchers.  How do you use variation in your training and practice regimen? Leave a comment below, and please share this article with anyone you think could benefit.