Two equal lines, one capped with outward-opening fins, the other with arrowheads: the first looks longer. In the 1960s, Marshall Segall and colleagues tested this Müller-Lyer illusion in more than a dozen populations. American students were among the most fooled; San foragers of the Kalahari, among the least. Growing up surrounded by right angles and buildings may play a role, but the explanation is still debated.
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.