Is Everyone Else an NPC? How the Brain Creates a Sense of Reality
Imagine spending several hours with a friend. They sit across from you, talk, laugh, and respond in ways you could not have predicted. While they are there, you do not doubt that their life is as real as yours. You sense that they see the world through their own eyes, carry thoughts you cannot hear, and continue thinking even when they fall silent.
Then you say goodbye. The door closes, and you are alone.
You know that your friend is travelling home and continuing with their life. Yet an unsettling thought can briefly appear: if they are no longer part of my immediate world, does their experience really continue? Are they still seeing, thinking, and feeling as vividly as I am? Or are they like a character in a game, waiting somewhere beyond the visible scene until I encounter them again?
Sometimes the feeling goes further. For a moment, it can seem as though you are the only fully real person the only point from which anything is actually being experienced. Everyone else appears to exist at a distance, while you remain trapped inside the own perspective, unable to step outside it and confirm that another inner world is truly there.
The fear is difficult to explain because it is usually not a genuine belief. You know that other people do not disappear when you stop looking at them. The unsettling part is the gap between knowing that they remain real and being able to feel the continuity of their reality.
How Can We Know That Other Minds Exist?
We experience our own consciousness directly. We do not study our facial expression to discover that we are sad or infer from our behaviour that we are in pain. We encounter our thoughts, emotions, and bodily sensations from within.
Our access to other people is different. We can recognize pain in someone’s face or hear distress in their voice, but we cannot experience their pain from the exact point at which they experience it. We cannot enter another person’s mind and see how the world appears from there.
In philosophy, this asymmetry is known as the problem of other minds: if we experience only our own mind directly, how can we know that other thinking and feeling minds exist?
René Descartes famously considered whether his senses might be deceiving him and whether the world he perceived could be an illusion. Even if everything else were false, however, there still had to be something doing the doubting. This led him to the statement, “I think, therefore I am.”
That certainty applies most directly to one’s own consciousness. We experience “I am thinking” from within; we reach the conclusion that someone else is thinking through observation. This gap makes room for the extreme philosophical position known as solipsism: if my mind is the only one whose existence I can know with absolute certainty, perhaps it is the only mind that exists.
Today, the same old doubt is often expressed through a modern metaphor: what if everyone else is an NPC?
In video games, non player characters appear to act and speak, but their behaviour is generated by a system. They become active when the player encounters them, while whatever happens beyond the visible scene is limited or not represented at all. The comparison can feel strangely familiar when we struggle to imagine another person’s life continuing after they leave us.
A related idea appears in philosophy as the philosophical zombie. This hypothetical being is assumed to look and behave exactly like a conscious human. It speaks, avoids injury, expresses love, and discusses its experiences, yet supposedly has no subjective life at all. There is nothing it feels like to be that being.
The philosophical zombie is not scientific evidence that real people lack consciousness. It is a thought experiment used to ask whether consciousness can be fully explained by physical processes. It also differs from an ordinary video game character: an NPC’s limitations can eventually be observed, while a philosophical zombie is defined as behaviourally indistinguishable from a conscious person.
Our inability to enter another person’s inner world does not mean that no such world exists. Absolute certainty and reasonable knowledge are not the same. In both science and ordinary life, we accept many things because they offer the strongest explanation of the evidence, not because we experience them directly.
Other people have bodies and nervous systems similar to ours. They avoid pain, learn from experience, produce information we did not know, and respond in ways we cannot control or predict. Their actions continue to affect the world when we are absent. The existence of thoughts, feelings, and individual points of view is the most convincing explanation of this complex behaviour.
We do not consciously repeat this argument every time we meet someone. The brain does much of the work automatically. It uses a person’s gaze to estimate what they are attending to, their voice to infer how they feel, and their movements to predict what they intend to do. This capacity to represent another person’s beliefs, emotions, and perspective is broadly known as theory of mind.
When a friend is with us, their face, voice, and unexpected responses continually reinforce the presence of a separate mind. When they leave, that stream of information ends. Memory and imagination must take its place.
The brain does not construct a detailed simulation of every person who exists outside our field of view. It would be neither useful nor possible to represent billions of simultaneous lives at full resolution. What fades, then, is not the other person’s existence but the vividness of our mental representation of it.
This should not automatically be described as a failure of “object permanence” in adults. Being unable to imagine someone’s ongoing life vividly is not the same as believing that they have ceased to exist.
At times, however, the distance becomes more intense. People may seem mechanical even while standing in front of us. Familiar faces may lose their emotional closeness, or the surrounding world may resemble a film set. We still know that nothing has physically changed, yet the feeling of reality that normally accompanies perception has weakened.
The philosophical and psychological questions meet here, but they are not identical. “Can I prove with absolute certainty that other people are conscious?” is a philosophical question. “Why do people feel unreal even though I know they are real?” is a scientific question about perception, emotion, and the sense of self.
How Does the Brain Separate “Me” from “Other”?
Before the brain can experience another body as belonging to someone else, it must distinguish our own body as “me.” This boundary feels so immediate that we rarely notice it being constructed. We look at our hand without asking whether it belongs to us, and we move without questioning who initiated the action.
Yet there is no single region in the brain that contains the self. The sense of self depends on several processes: feeling that our body belongs to us, locating ourselves somewhere in space, experiencing ourselves as the source of our actions, and connecting memories across time into a continuing personal history.
One of the best known demonstrations of this flexibility is the rubber hand illusion, published by Matthew Botvinick and Jonathan Cohen in 1998. A participant’s real hand is hidden while a realistic rubber hand is placed in view. When the visible artificial hand and the hidden real hand are stroked at the same time and in the same rhythm, many participants begin to feel as though the rubber hand belongs to them.
They still know that it is made of rubber. Nevertheless, when what they see matches what they feel, the brain can temporarily include the artificial hand in its model of the body. When the timing of the two touches is disrupted, the illusion usually weakens. Bodily ownership therefore depends not only on what we know but also on the agreement between vision, touch, and information about the body’s position.
In 2007, Bigna Lenggenhager and her colleagues extended a similar method to the whole body. Participants viewed an image of their body from several metres away through a virtual reality system. When visual and tactile signals were synchronized, some participants felt more closely identified with the virtual body and experienced a shift in their perceived location towards it.
No one literally left their body. What changed was the brain’s temporary answer to two normally unquestioned questions: Which body is mine, and where am I?
These experiments do not show that the self is fake. They show that the bodily self depends on the integration of several genuine signals. Constructed does not mean imaginary; it means assembled from information.
Another component of selfhood is the sense of agency: the feeling that we are the source of our actions. The brain predicts the sensory consequences of our movements. When we decide to lift a hand and receive the visual and bodily feedback we expected, the action feels like ours.
This helps explain why it is difficult to tickle ourselves. The brain predicts the touch produced by our own movement and reduces part of the sensory response. Someone else’s movement cannot be predicted with the same precision, so their touch feels stronger. The brain is continually estimating whether an event was produced by the self or by something outside it.
Our identity also extends beyond the present body. We connect our memories, relationships, decisions, and plans into the story of a single person. Although we have changed substantially since childhood, we still refer to every earlier version as “me.” This continuing personal history is sometimes called the narrative self.
While constructing a model of the self, the brain also models other minds. When a friend suddenly becomes quiet, we do not merely notice the absence of speech; we wonder whether they are hurt, distracted, or uncomfortable. When someone reaches for a glass, we can often infer their goal before the movement is complete.
In a 2003 brain imaging study by Rebecca Saxe and Nancy Kanwisher, activity around the temporoparietal junction increased when participants reasoned about other people’s beliefs. Later research showed that regions including the medial prefrontal cortex also participate in a broader network involved in social thought.
There is therefore no single “empathy centre” or point in the brain that decides whether another person is real. Systems involved in recognizing faces, interpreting movement, recalling past interactions, assessing emotional expression, and comparing perspectives work together. Their combined activity allows us to experience another person not merely as a body but as a subject with a life continuing inside them.
But why can we still recognize someone perfectly and yet feel that something about them is missing?
Why Can Something Be Real Without Feeling Real?
A sense of reality depends on more than identifying what we see. Perception is connected to memory, bodily response, familiarity, and emotional significance. When these processes agree, we do not need to ask whether our surroundings are real.
A familiar face is not simply a visual arrangement of eyes, nose, and mouth. It is accompanied by previous conversations, shared memories, and emotional closeness. Recognizing the face and feeling that this is truly that person are closely connected, but they are not identical.
Small cracks between knowledge and familiarity can occur in ordinary experience. Repeat a word for long enough and it may temporarily lose its meaning, becoming a strange sequence of sounds. Look closely at your reflection for an extended period and parts of your face may begin to appear unfamiliar. Your knowledge has not changed, but the effortless feeling of familiarity has weakened.
A stronger separation can affect people and places. Someone may recognize their home, their street, or a loved one while everything feels distant, flat, or artificial. The facts remain intact, but the emotional closeness usually attached to them is reduced.
Perception is not made only from information arriving through the eyes and ears. The brain also evaluates what an object, place, or person means to us. A familiar face or a threatening sound can alter heart rate, breathing, muscular tension, and skin conductance before we consciously notice the response.
The perception of signals coming from within the body is called interoception. Hunger, thirst, and a racing heart are obvious examples, but internal bodily information may also contribute to the intensity of emotion and to how present we feel within an experience.
Research led by Mary Phillips in 2001 and Mauricio Sierra in 2002 suggested that experiences of unreality may be accompanied by altered emotional and bodily responses.
Phillips and her colleagues measured brain activity while people with depersonalization viewed emotional images. The participants understood what the images represented, but activity in some regions associated with emotional processing differed from that of the comparison group.
Sierra’s team measured skin conductance, which reflects small changes in bodily arousal. In the depersonalization group, automatic responses to certain unpleasant stimuli were weaker or appeared later.
These findings suggest that the difficulty may not always lie in understanding what is being seen. A person can know that a view is beautiful without feeling moved by it. They can recognize someone they love without experiencing the expected sense of closeness.
The studies were small, however, and do not prove that one brain region or mechanism causes the entire experience. There is currently no brain scan that can diagnose depersonalization or derealization.
A more extreme example of the separation between recognition and familiarity can be found in Capgras delusion. In this rare condition, a person may recognize the appearance of someone close to them while believing that the individual has been replaced by an identical impostor.
Studies involving small groups of patients in the 1990s found that some did not show the usual increase in skin conductance when viewing familiar faces. This suggested that visual recognition and the automatic feeling of familiarity might become separated in certain cases.
Capgras and derealization are not the same. A person experiencing Capgras may genuinely believe that someone has been replaced. During derealization, people usually know that those around them have not changed; they only report that they feel unreal or unfamiliar.
Recognizing something, believing in its existence, and feeling its reality are connected but separable processes. Most of the time they fit together so smoothly that we never notice the difference. When that connection weakens, the world can remain recognizable while losing its sense of immediacy.
Why Can the World Feel Like a Dream or a Game?
When the change in reality feeling concerns the external world, it is called derealization. Surroundings may seem distant, foggy, lifeless, unusually sharp, or artificial. Familiar places can appear strange, people may look like actors or robots, and time may seem to move differently.
When the experience concerns the self, it is called depersonalization. People may feel detached from their thoughts, emotions, voice, or body. They know that they are speaking and moving, yet their actions may appear automatic or strangely remote.
The two often occur together because “I am here” and “This place is real” are not entirely separate experiences. When closeness to the self weakens, the world may also feel more distant.
Crucially, awareness of reality is usually preserved. A person may say that the room resembles a film set without believing that it literally is one. Other people may look robotic without the person believing that they are machines. The conflict between knowledge and feeling is often what makes the experience frightening.
There is no single cause. Intense anxiety, panic, trauma, prolonged stress, sleep deprivation, depression, and certain psychoactive substances may trigger depersonalization or derealization. Monotony and reduced social interaction may also intensify feelings of alienation in some people, although they have not been established as direct causes of the disorder.
Under intense stress, attention narrows towards possible danger. Heart rate, breathing, and muscular tension change. This alarm state can be useful for a short period, but when it becomes intense or prolonged, it may interfere with the integrated and familiar experience of the environment.
During a panic attack, a racing heart, breathlessness, or dizziness can lead someone to monitor their body constantly. Rapid breathing may also alter carbon dioxide levels in the blood, contributing to tingling, light-headedness, and visual changes.
If the person interprets these sensations as evidence that they are losing their mind or that the world is becoming unreal, fear increases. Greater fear intensifies bodily arousal, which may make the feeling of unreality stronger. The experience is genuine, but repeatedly monitoring it can help keep it at the centre of attention.
During overwhelming events, some people feel mentally separated from what is happening. The event may seem to be happening to someone else, time may slow down, or the surroundings may resemble a scene in a film. These disruptions fall within the broader concept of dissociation, in which processes that usually work together such as emotion, memory, bodily awareness, and identity become less integrated.
Not every dissociative experience is a disorder, and not every episode of derealization is caused by trauma.
One influential model proposed by Mauricio Sierra and German Berrios suggests that, under intense threat, frontal regions of the brain may inhibit excessive emotional responses generated by limbic systems. This response could function as a way of reducing overwhelming emotion.
The cost may be that fear is not the only feeling weakened. Closeness, affection, excitement, and familiarity the qualities that make the world feel alive may also become muted. Subjectively, it can feel as though a sheet of glass has appeared between the person and life.
This is an explanatory model, not a mechanism proven to account for every case. Many brain imaging studies in this area involve small groups, and it is not always clear whether the observed differences are causes or consequences of the condition.
Another approach comes from predictive processing. According to these models, the brain does not passively record reality. It continually generates predictions about the external world and the body, then updates them using incoming sensory information.
When we see a friend, their face, voice, our memories of them, and our bodily responses normally point towards the same person. During intense anxiety or dissociation, the weight assigned to these signals may change. Attention can become trapped in the heartbeat, breathing, or the question “Do I feel normal yet?” Alternatively, bodily and emotional responses may become muted, leaving the environment perceptually present but internally distant.
These models offer possible explanations, but no reliable biological test currently identifies depersonalization or derealization.
Sleep deprivation can worsen attention, memory, and emotional regulation, making unreal sensations more likely in vulnerable people. Cannabis and some hallucinogens can also alter perception and the sense of time and embodiment. In some cases, symptoms continue after the expected effects of the substance have ended.
Video games and screens, however, have not been shown to directly make people perceive others as NPCs. “NPC,” “simulation,” and “film” are modern metaphors for a much older experience. In earlier periods, people described the same alienation as living behind glass or watching life unfold on a theatre stage. Technology changes the language of the feeling, not necessarily the feeling itself.
When Does the Feeling Become a Symptom?
A few seconds in which the world appears strange, or a brief difficulty imagining the full lives of other people, does not by itself indicate a psychological disorder. Duration, intensity, recurrence, distress, and the effect on daily life all matter.
Short experiences of unreality are relatively common. Clinically significant depersonalization-derealization disorder, however, is estimated to affect roughly one to two per cent of the population. For the experience to be considered a disorder, it must be persistent or recurrent, cause significant distress, or interfere with work, school, relationships, or everyday responsibilities.
One of its defining features is that reality testing usually remains intact. A person experiencing derealization generally says, “The world feels unreal,” rather than, “The world is unreal.”
During psychosis, by contrast, ideas that other people are artificial, that the world was constructed specifically for the individual, or that ordinary events contain hidden personal messages may become fixed beliefs. They can continue despite strong evidence against them.
The distinction is not always easy to make alone. Professional assessment is important if uncertainty becomes a firm conviction, or if it is accompanied by hallucinations, serious confusion, several days with almost no sleep, uncontrolled behaviour, or concerns about personal safety.
Similar experiences can also occur with migraines, certain seizures, head injuries, medications, or substance use. Sudden symptoms after a head injury especially with fainting, seizures, a severe headache, speech difficulties, weakness, or significant visual changes require medical attention. Symptoms that begin after psychoactive substance use and continue beyond the expected period of intoxication should also be assessed.
Treatment depends on what is sustaining the experience. If it occurs with panic attacks, the panic cycle may need to be addressed. If it is connected to trauma, depression, anxiety, or sleep disruption, those conditions may also require treatment. Psychotherapy is the main clinical approach.
Cognitive behavioural methods aim to reduce catastrophic interpretations and constant self-monitoring. Thoughts such as “What if I am losing my mind?” or “Do I feel real yet?” can repeatedly pull attention back towards the symptom.
A recent feasibility study tested cognitive behavioural therapy adapted for depersonalization-derealization disorder with 30 participants. The approach appeared feasible and acceptable, but the study was too small to establish its effectiveness conclusively. Larger trials are still needed.
Evidence for medication is more limited. No medication has been conclusively shown to treat depersonalization-derealization disorder itself, though medication may be used for accompanying depression, panic, or severe anxiety.
Grounding methods that direct attention towards visible objects, physical contact with the floor, and sounds in the environment may help some people reconnect with the present moment. The goal is not to test reality repeatedly, but to move attention away from an internal loop and back towards ongoing experience.
Sleep, movement, social contact, and avoiding psychoactive substances will not resolve every case, but they may reduce factors that strain the nervous system. Constantly reading simulation theories, checking one’s reflection, or testing whether the world feels real can provide temporary reassurance while reinforcing the idea that an urgent threat must be solved.
Overcoming this feeling does not require absolute philosophical proof that the universe is real. No one possesses access to reality from every possible point of view. The existence of other minds remains the most coherent explanation of the complex, independent, and interactive world we encounter.
When you are not thinking about a friend, they are still experiencing the world from their own perspective. They feel themselves at its centre, just as you do, and they cannot directly know what you are doing at that moment. Every person is sometimes an unseen character in someone else’s story, while remaining the uninterrupted first-person subject of their own.
The fact that the brain constructs models of selfhood and reality does not make them false. Colour also emerges from the meeting of light with the brain’s visual processes, yet a rainbow is not imaginary.
When the feeling of reality weakens, the world does not disappear. What temporarily falls silent is the invisible connection that binds our bodies, emotions, surroundings, and other people into a single lived world.
This article is intended for information and awareness only. It is not a substitute for diagnosis or treatment. If feelings of unreality are persistent, recurrent, or interfering with daily life, consider speaking with a qualified health professional.
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Merck Manual Professional Edition. Depersonalization/Derealization Disorder. Clinical overview
