Spacing study sessions out beats cramming, a finding that's held up for 150 years

In 1885 Hermann Ebbinghaus found he remembered nonsense syllables far better when he reviewed them on separate days rather than all at once. Psychologists call this the spacing effect, and it's one of the most replicated findings in memory research: spaced study beats cramming the same total time into one sitting.

— Hermann Ebbinghaus, Über das Gedächtnis (Memory: A Contribution to Experimental Psychology) — 1885; the spacing effect has since been replicated in hundreds of studies