In 1978, Ellen Langer had people ask to cut in line at a photocopier. With no reason given, 60% let them. With “because I'm in a rush,” 94%. And with “because I have to make copies,” a completely empty reason, still 93%. For a small favor, the shape of an explanation is enough. For a big one, you need a real reason.
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.