If you're interested in scientific studies on how memory and information retention can be improved, you might want to check out a 2007 report called
Increasing Retention without Increasing Study Time (PDF), published in
Current Directions in Psychological Science.
This particular paper is only about 4 pages long, so it's fairly digestible although the primary field of learning studied here is mathematics, so results may vary if a different field is considered.
A bit of a surprising quote from the abstract is as follows:
"Our results suggest that a single session devoted to the study of some material should continue long enough to ensure that mastery is achieved but that immediate further study of the same material is an inefficient use of time."
Normally I'd consider repetition to be a good thing. The study also focuses on spaced repetition, so there are some comments on that. I'm sure there have been other such studies done since 2007, but I happen to come across this one and thought it was interesting enough to share.
Now on to this week's hand-picked productivity links!