two mechanisms
spacing and retrieval practice are not the same thing
They are often used together, but separating them leads to clearer claims and better study decisions.
Spacing
Study or review episodes are distributed over time instead of being concentrated in one session.
Retrieval practice
The learner attempts to bring an answer to mind rather than only rereading the material.
Feedback
After an attempt, seeing the correct answer helps identify errors and supplies material for another retrieval attempt.
Scheduling
A system decides when an item returns. The schedule may be fixed, expanding, or adaptive to recorded performance.
what research supports
distributed reviews can outperform massed study
The research supports careful conclusions, not a single universal timetable.
Cepeda and colleagues synthesized hundreds of distributed-practice assessments and found that the relationship between the spacing interval and later retention depends partly on the intended retention interval. Put simply, the best gap is not fixed independently of how long the learner wants the material to last.
Rawson and Dunlosky examined repeated retrieval and relearning of conceptual material. Their experiments found substantial value from relearning at widely spaced intervals, while also showing that more initial practice and more later relearning do not contribute in a simple additive way.
Kang and colleagues compared expanding and equal-interval retrieval schedules for foreign vocabulary. The schedules produced equivalent final-test recall in that study, while the expanding schedule produced higher average recall during training. This is a useful reminder that the best schedule can depend on the outcome being optimized.
in biu
how biu uses review history
The approved product claim describes observable scheduling behavior without predicting the exact moment someone will forget.
- 01
A flashcard enters the review workflow
The card may be generated from supported study material and becomes available for practice.
- 02
The learner attempts an answer
That attempt creates review history for the card instead of treating every review as identical.
- 03
A correct answer increases the interval
biu schedules each card from your review history and increases the interval when you answer correctly.
- 04
Due cards return in a later quiz
The daily quiz brings scheduled material back without requiring the learner to plan every review date manually.
primary sources
research cited in this guide
These records provide abstracts, authorship, publication details, and DOI identifiers for the studies summarized above.
- Distributed practice in verbal recall tasks: a review and quantitative synthesis
Cepeda et al., Psychological Bulletin, 2006. A meta-analysis of 839 assessments across 317 experiments examining spacing and retention intervals.
- Optimizing schedules of retrieval practice for durable and efficient learning
Rawson and Dunlosky, Journal of Experimental Psychology: General, 2011. Three experiments examining initial retrieval and later relearning sessions.
- Retrieval practice over the long term: should spacing be expanding or equal-interval?
Kang et al., Psychonomic Bulletin & Review, 2014. A study comparing expanding and equal-interval retrieval schedules for foreign vocabulary.