Psychologists have seen it since the 1930s: a behavior rewarded every time dies out quickly once rewards stop. If it was rewarded only now and then, at random, it keeps going far longer with nothing in return. It's the partial reinforcement effect, the core principle of slot machines, and a clue to why we refresh feeds endlessly.
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.