Science
The science of retention
Why do we remember — and why do we forget? What the studies say, and how Slonto turns it into a concrete method.
The best-established effects in the psychology of memory
Results replicated for over a century explain durable retention.
Testing effect
Testing yourself (active recall) fixes things better than re-reading. Roediger & Karpicke (2006): one week later, the tested group retained far more than the group that re-read the same text. Dunlosky et al. (2013) rank practice testing among the two most effective techniques.
Spacing effect
Spreading reminders over time beats cramming. Cepeda et al. (2006), a meta-analysis of 317 experiments: the more distant the deadline, the longer the optimal spacing.
Forgetting curve
Without reminders, memory declines fast. Ebbinghaus (1885) measured it, Murre & Dros (2015) replicated it. Caveat: those figures come from nonsense syllables — the dynamic matters, not an absolute percentage.
Retention vs performance
Learning in several passes may feel slower in the moment but produces far more durable memory. Spaced reminders create a "desirable difficulty" that strengthens the trace.
How Slonto turns science into a method
A lesson is only validated once the quiz is passed: no passive consumption.
Every lesson feeds question/answer cards, actively retrieved.
The algorithm brings each card back just before forgetting, then spaces it further.
A short daily session turns effort into a habit — that's what carries the first two weeks.
What about dropout?
Knowledge retention is useless if the student quits first. More than half of online learners drop out within the first two weeks. Daily review, the streak and the community tackle early dropout at the same time as forgetting.
What's next?
In 2027 we're improving spaced repetition further (SRS v2, the FSRS-5 algorithm) to boost your students' long-term retention.
Sources
Every figure cited is verifiable and dated:
- Ebbinghaus, H. (1885). Über das Gedächtnis. — Murre & Dros (2015), PLOS ONE 10(7):e0120644, doi:10.1371/journal.pone.0120644
- Roediger & Karpicke (2006). Test-Enhanced Learning. Psychological Science 17(3):249-255, doi:10.1111/j.1467-9280.2006.01693.x
- Karpicke & Roediger (2007). Repeated retrieval during learning is the key to long-term retention. Journal of Memory and Language 57:151-162.
- Cepeda, Pashler, Vul, Wixted & Rohrer (2006). Distributed practice in verbal recall tasks. Psychological Bulletin 132(3):354-380, doi:10.1037/0033-2909.132.3.354
- Dunlosky, Rawson, Marsh, Nathan & Willingham (2013). Improving Students' Learning With Effective Learning Techniques. Psychological Science in the Public Interest 14(1):4-58, doi:10.1177/1529100612453266
- Ye et al. (2022). A Stochastic Shortest Path Algorithm for Optimizing Spaced Repetition Scheduling (FSRS), KDD.
What we don't promise
Studies measure trends across varied groups and content; exact numbers vary. Slonto presents these data as robust trends, not a guarantee of results. The method is measurable and will evolve (SRS v2 / FSRS-5 in 2027).