# What is an “observer” in quantum mechanics? [duplicate]

This question already has an answer here:

i read about the electrons double slit experiment, when both slits are open, electrons will form an interference pattern, but when there is a detector put to "observe" this weird behaviour, the outcome is different, the elctrons dont form interference pattern anymore because when there is an "observer" the nature force the electron to chose a state. i found this confusing because why in the first case (without detector thing) do the electrons still form an interference while the humans are also observing. in my understanding an observer is one that can take informations, dont the humans thus in this experiment an obsever too?.