A new study published in the journal Religion, Brain & Behavior sheds light on a chilling but common human experience: the eerie sensation that someone—or something—is nearby, even when no one else is present. The researchers found that this “feeling of presence” becomes more likely when people are left alone in the dark with their senses dulled, and especially when they are uncertain about what might be happening around them. Under these conditions, people’s brains may rely more heavily on internal cues and prior expectations, sometimes creating the unsettling impression that another agent is nearby.
The researchers aimed to understand how these feelings arise and whether they are shaped primarily by internal uncertainty, social expectations, or individual personality traits. This study fits into a larger effort to understand how people come to perceive invisible agents—like ghosts or spirits—not as a result of hallucinations or delusions, but as part of normal cognitive processes shaped by evolution, culture, and physiology.
These eerie feelings of being watched or not being alone—technically called “feelings of presence”—are common in folklore and religious stories across cultures and history. People have long reported sensing ghosts, spirits, or other unseen beings, especially in dark, isolated, or emotionally intense situations. But modern neuroscience suggests these sensations might not require the supernatural to explain them. Instead, they may result from the brain’s attempt to make sense of uncertain or incomplete information.
“I am generally interested in experiences often deemed spiritual, religious, psychedelic, or otherwise special,” explained study author Jana Nenadalová, who is affiliated with the LEVYNA Laboratory for the Experimental Research of Religion at Masaryk University.
“I was doing experiments with sensory deprivation, used as a tool for eliciting spiritual experiences in participants in the laboratory context. Interestingly, besides spiritual experiences, participants across two different studies with various (spiritual, religious, secular) backgrounds sometimes reported a very similar feeling: as if there was somebody else present in the lab with them during the sensory deprivation trial, watching them, pacing around them, etc. These feelings were not in any way connected to their spirituality, and participants felt uneasy, anxious, or uncertain. So I decided to run a separate study on this interesting phenomenon.”
To explore how these feelings are produced, the researchers designed an experiment involving 126 university students in the Czech Republic. Each participant entered a darkened laboratory room where they sat alone for 30 minutes while wearing a sleeping mask and earplugs. These conditions muted their visual and auditory input and simulated a type of mild sensory deprivation.
Before the sensory deprivation phase, half of the participants were told that someone might accidentally enter the room during the session. This instruction served as a kind of social or cultural “priming,” planting the idea that another person could appear. The other half were not given this information and served as a control group.
Throughout the experiment, the researchers measured participants’ physiological arousal using sensors that tracked changes in skin conductance—a common method for detecting stress or anxiety. After the session, participants completed a set of questionnaires and underwent interviews to report whether they had felt uncertain, anxious, or experienced any unusual sensations, including the feeling that someone else was present.
The results showed that internal uncertainty—measured through both physiological arousal and self-reports—was the most consistent predictor of the feeling of presence. People who reported higher levels of uncertainty were more likely to say they felt someone was near them, especially through non-visual and non-auditory channels like touch or general emotional impression. In other words, when people could not rely on their sight or hearing, they were more likely to interpret odd bodily sensations or ambiguous feelings as evidence that someone else was nearby.
Interestingly, the manipulation designed to prime participants with the idea that someone might enter the room had only a limited effect. It did not increase the frequency or intensity of reported presences across the board. However, it did show a relationship with feelings of being touched, but only when combined with physiological arousal. This suggests that cultural expectations might play a role in shaping the type of presence people feel, but not necessarily whether they feel one at all.
The researchers also investigated whether certain personality traits made people more likely to feel presences. Two traits stood out: imaginative suggestibility (the tendency to respond strongly to mental imagery or suggestion) and fantasy proneness (the tendency to become absorbed in internal fantasies). People with higher imaginative suggestibility were more likely to report a felt presence—particularly when their uncertainty was also high.
However, those with higher fantasy proneness were actually less likely to report visual presences, and in some cases less likely to report touch-related presences. “Contrary to expectations, fantasy proneness (the propensity to daydream or fantasize) seems to prevent visual feelings of presence, perhaps because people high on this disposition just start daydreaming when they are alone and there is nothing around, which prevents them from being uncertain,” Nenadalová said.
Interviews with participants added depth to the numerical findings. Many described ambiguous feelings or moments of unease, wondering if someone might be nearby without actually seeing or hearing anything. A few mentioned faint sounds, like footsteps or the rustling of papers, even though earplugs were worn.
Others described strange sensations, like fleeting touches on their skin or feelings of being watched. Some participants consciously tried to suppress thoughts that someone might be present, while others reported emotionally vivid experiences of not being alone. Most of these eerie sensations were linked in participants’ own accounts to feelings of uncertainty or fear.
Only a few participants described full sensory hallucinations. More often, the feeling of presence was a vague impression or bodily sensation, like someone standing nearby or brushing past them. These sensations align with what psychologists and neuroscientists have observed in other contexts, such as sensory isolation tanks, extreme environments, or even during intense grief or trauma.
The researchers interpreted their findings through the lens of a cognitive theory known as predictive processing. According to this theory, the brain is constantly generating predictions about what is happening in the environment and checking those predictions against incoming sensory data. When the sensory input is weak or unclear—like in a dark, silent room—the brain leans more heavily on prior expectations.
If a person already expects that someone might be nearby, or if their body is producing signs of anxiety (like sweating or a racing heart), the brain might interpret that combination as confirmation of another presence. This can create a feedback loop: vague bodily cues lead to anxious thoughts about being watched, which in turn intensify those bodily sensations, reinforcing the feeling.
This study suggests that the feeling of presence might be an adaptive side effect of how human brains evolved to handle uncertain situations. From an evolutionary perspective, it is often safer to err on the side of assuming there is a hidden threat—like a predator or enemy—than to ignore one that might be real. That bias toward agency detection could help explain why so many people experience ghostly sensations or develop beliefs in invisible agents, especially in situations where they feel vulnerable or uncertain.
“It is not weird nor pathological to feel (and fear) the presence of unseen others when we are alone in dark, silent, or just sensorily ambiguous environments,” Nenadalová told PsyPost. “Having a feeling as if there is somebody pacing behind us, watching us from behind a bush, or hiding in dark corners of our basement seems to be a normal reaction of our cognitive system facing uncertainty.”
However, the study has limitations. The semantic priming manipulation may have been too subtle to produce strong effects. Participants may not have taken the suggestion of someone entering the room very seriously. Also, while electrodermal activity is a useful indicator of arousal, it cannot distinguish between types of stress or excitement. The reliance on self-report measures and interviews means that subjective interpretations could vary widely across individuals.
Future research could explore stronger or more emotionally evocative priming strategies to see whether more vivid expectations about other agents lead to stronger feelings of presence. Researchers might also investigate how different types of prior beliefs—such as religious or spiritual worldviews—shape the content of these sensations. And while this study focused on eerie, unpleasant presences, other work has found that some people experience comforting or guiding presences in similar conditions. Understanding the full range of these experiences could shed light on both ordinary cognitive functioning and extraordinary beliefs.
Looking ahead, Nenadalová plans “to focus also on other types of feelings of presence, especially in connection with other psychological dispositions—like phenomenological control (imaginative suggestibility)—and specialized practices where people are willingly training themselves to be able to experience a presence of various beings.”
The study, “Sensing ghosts and other dangerous beings: uncertainty, sensory deprivation, and the feeling of presence,” was authored by Jana Nenadalová and Dan Řezníček.
