A famous 2000 study found that a stall with 24 jams got 3% of shoppers to buy, versus 30% with 6 jams. But a 2010 review of 50 experiments found an average effect of nearly zero. Too many options can discourage in some cases, such as when you don't know what you want or items are hard to compare, but it isn't a general law.
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.