Cramming works right up until the moment it's tested
A German psychologist memorized nonsense syllables alone in a room and discovered why school calendars fight against memory itself.
In the 1880s, Hermann Ebbinghaus ran perhaps the loneliest experiments in the history of psychology: alone, with no subjects but himself, he memorized long lists of meaningless syllables and tracked, with punishing precision, how fast he forgot them. Out of that self-experimentation came two durable findings — the forgetting curve, which showed memory decaying fastest in the hours right after learning, and the spacing effect, which showed that breaking study into separated sessions beat cramming the same material into one sitting, even when total study time was identical.
The spacing effect has since been replicated across languages, ages, and subjects with unusual consistency for psychology. Spreading four hours of study across a week produces better long-term retention than the same four hours the night before a test — not a marginal edge, but a substantial, repeatable one.
Most school calendars do the opposite by design. A unit gets taught, tested at its end, and rarely revisited — the material's last contact with the student is often the exam meant to prove they learned it. Cramming isn't a student failure to plan ahead; it's a reasonable response to a system that only ever asks about what was covered most recently.
Ebbinghaus figured this out with nothing but a notebook and his own forgetting. Most classrooms still schedule as if he never published it.