A review of more than 300 experiments is clear: for the same total study time, spacing sessions across days makes material stick far longer than cramming it all at once. Better still, the ideal gap between reviews grows with how long you want to remember. Cramming works for tomorrow's exam, then it all evaporates.
Remembering is not replaying a recording — it is rebuilding. Each time you recall a memory, it becomes temporarily malleable and can be altered before being stored again. That is why two people can sincerely remember the same event… differently.
In 2003, Johnson and Goldstein compared European countries. Where you must tick a box to become a donor, consent rates ranged from 4% to 28%. Where you're a donor by default unless you opt out, they topped 85%. People aren't more generous on one side; most simply stick with whatever option was chosen for them.