“Felt presence” is a phenomenon where you feel that someone or some entity is near you, sometimes accompanied by an actual hallucination of some form. The phenomenon occurs in sleep paralysis (see this blog post) but also in certain neurological conditions. It can even be induced in healthy people while they’re awake. (View Highlight)
The psychological quality of felt presence is typically associated with feelings of fear and anxiety. In the case of sleep paralysis, which is a state of paralysis that sometimes persists shortly upon waking from sleep, the feeling of presence often takes the form of a threatening intruder hovering near the sleeper. This threatening feeling of presence is persistent in most sleep paralysis episodes, and it has been associated with anxiety and depression. (View Highlight)
This commonality provides some support for a brain basis of felt presence as a neuropsychological phenomenon that involves electrophysiological glitches, particularly in temporal areas of the brain. There also seem to be some changes in activation in subcortical areas such as the amygdala and hippocampus. Even in sleep paralysis episodes, it’s possible that felt presence is enabled via high amygdala activation levels during REM sleep, which induce a hypervigilant state. (View Highlight)
Besides these spontaneous episodes, felt presence can be artificially induced both behaviorally and biologically in healthy subjects, reinforcing the notion that it is a neuropsychological phenomenon. Magnetic stimulation in temporal areas of the brain can create illusions of felt presence. Or, a paradigm called the master-slave robotic system that leads to sensorimotor confusion can also induce feelings of presence. (View Highlight)
In the majority of cases, felt presence is associated with unpleasant feelings like fear and sadness, although it sometimes takes a positive form, in which the presence feels like a friend, family member, or religious entity. Some have suggested that the feelings associated with the presence are determined by its felt location. For instance, a presence on the right side might be more associated with fear and anxiety whereas on the left side the presence is suggested to be less unpleasant. Nevertheless, most instances occurring during sleep paralysis are associated with negative feelings. (View Highlight)
