Why does it sometimes seem like you’re not alone in the room? Scientific explanationScience and technology13:03 | 08 April 2023

One of the largest studies on this topic was carried out as early as 1894. The Society for Psychic Research (SPR) has released a “hallucination count” that includes more than 17,000 people. The purpose of the survey was to find out how often people had visions of death.

The SPR concluded that such experiences were too frequent to be random (one in every 43 people surveyed). In 1886, the SPR published Living Ghosts, which consisted of 701 cases of telepathy, premonition, and other unusual phenomena. For example, one of the contributors to the collection described an experience where a night vision deterred him from taking a morning boat ride the next day. He later learned that everyone who swam was dead.

At the time, Living Ghosts was criticized for being unscientific. But modern science offers ideas for understanding “supernatural” experiences. Visions turned out to be particularly strongly linked to sleep paralysis, which about 7% of adults experience at least once in their lives. So why does sleep paralysis create the feeling of someone else’s presence? Some researchers have focused on specific features of waking up in such an unusual state. In 2007, sleep researchers argued that if we wake up paralyzed, our instincts will make us feel threatened, so the mind will fill in the blanks.

Additionally, it turns out that visions can be part of Parkinson’s disease, psychosis, near-death experiences, and mourning. A series of experiments in 2014 also showed that disruption of sensory expectations creates a sense of presence in some healthy people. This logic can also be applied to conditions such as sleep paralysis. All our usual knowledge of the body and sensations is distorted in this context, so we may feel that there is someone “other” with us.