I’m reviewing the vocabulary I learned in today’s Spanish class. The last time I went through my flashcard deck, I got all of those new words right. Should I keep studying? Or, is it time to move on to my Algebra?
In a recently published paper, Shibata and colleagues argue that overlearning benefits long-term memory formation. That is: I should keep studying, because that extra level of work — above and beyond what’s required to get all my flashcards correct — protects these new memories from later interference.
(If you want the neurotransmitter details, Shibata finds that overlearning, which he calls “hyperstabilization[,] is associated with an abrupt shift from glutamate-dominant excitatory to GABA-dominant inhibitory processing in early visual areas. Hyperstabilization contrasts with passive and slower stabilization, which is associated with a mere reduction of excitatory dominance to baseline levels” p. 470. Got that?)
And yet, there’s a reason I put that question mark in the title of this article. Earlier researchers have found that overlearning just doesn’t work. (Doug Rohrer and Hal Pashler have published on this topic here and here.)
For the time being, I’m inclined to believe Rohrer and Pashler. Why? Because Shibata’s research paradigm showed a change in neuotransmitters after 2 days. Rohrer and Pashler’s paradigm showed no benefits for learning after 1 month.
In my view, teachers ought to be more interested in learning than in GABA and glutamate; and we ought to be less impressed by results obtained after 48 hours than by results obtained after 4 weeks.
(To be clear: I am interested in neurotransmitters. But, as a teacher, I’m MUCH more interested in demonstrated learning.)
So, for the time being, I’m will continue to recommend that students and teachers not emphasize overlearning. However, I will add an asterisk to that advice: as of today, our understanding of the neural results of overlearning is far from complete.
