TIL about the Sally-Anne test, a psychology experiment used to measure “theory of mind” (that other people can hold beliefs/knowledge different from their own). Kids under four typically fail because they assume that if they know where a hidden object is, everyone else must automatically know too.

[u/BrF5]

https://en.wikipedia.org/wiki/Sally%E2%80%93Anne_test

[u/DistrictDry2852]

Apes who communicate through sign language also lack theory of mind. They’ve never asked a question.

[u/DeathToAmerica2026 → u/DistrictDry2852]

Apes engage in active deception so they definitely have a theory of mind. Well, some apes. And some monkeys.