A common childhood phobia is the fear of a monster under the bed or similarly a monster in the closet or wardrobe. It is associated with the fear of the dark, the fear that there are monsters that cannot be seen due to the darkness.[1]
Origin
A theorised origin of the fear of monsters under the bed is that it may have evolved by human ancestors to avoid attacks by predators. Sexual size dimorphism of the human ancestor Australopithecus afarensis may have led females to sleep in trees and males to sleep on the ground, possibly leading females to anticipate attacks from below and males anticipating attacks from around them. A 2021 study interviewed boys and men and girls and women and found that males recalled monsters in their dreams beside them at higher rates than below them, but for females there was not much difference.[2]
American psychologist Peter Gray suggests that the fear relates to the possibility of monsters hiding in "any place where you can't see", and that the connection to the bed in particular may arise from examples seen on television or in stories, saying that "I would imagine the basic fear is innate, but the specific forms of the fear would probably be influenced by experience".[1]
Monsters, Inc., a 2001 Pixar film in which screams of children are harvested as energy through doors that activate portals to children's bedroom closets
