In 2011, psychologists handed moviegoers a bucket of popcorn that was either fresh or stale. People who didn't usually eat popcorn at the movies left the stale stuff. Regulars ate about as much stale as fresh: the cinema triggered the habit, not the taste. In a meeting room, the effect vanished. And when they had to eat with their non-dominant hand, even regulars cut back on the stale popcorn.
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.