Many animals make tears to protect their eyes, but none has been reliably observed shedding them out of emotion. Researchers see crying as a social signal. In 2009, a team digitally erased the tears from photos of crying faces: without them, viewers rated the faces as far less sad, sometimes even neutral.
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.