system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do some people 'freeze' when they get scared. Shouldn't they enter fight or flight mode? What happens with your body in such a situation?

It doesn't make sense to me that when a human gets scared his whole body 'freezes'. Wouldn't it maximise your chance of surviving if you entered fight or flight mode?
gpt
freezing is a form of defense. you see it commonly in rabbits and deer. a moving animal is easier for a predator to spot. by holding still, there is some chance that the predator will move on, or the prey will get more time to assess the situation.

it's obviously rather detrimental when a car is about to hit you, but we evolved with lions, not toyotas.