What Accounts for Ghost Encounters?

by Brian Dunning
January 13, 2026

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Last month I did a show asking the question of whether ghosts might exist. This was a quick survey through the realms of physics and energy, observation and the scientific method, even alleged religious justifications for ghosts. We found nothing. No replicable observations in need of an explanation, no gaps in our standard model that a ghost could nicely fill, and no way that a single undefined phenomenon could fulfill all of the characteristics believers assign to it. And yet, people still have ghostly experiences. They have them every day. Many have no doubt that a ghost — of some kind — was responsible for that experience. And so we're going to continue today by answering what the true causes for these experiences could be. If it's not a ghost, it has to be something. But what? Today we're going to lay it all out.

I'm fortunate to have a number of friends who are skeptical investigators, actually going out into the field and investigating ghost reports in person. Sometimes this is accompanying friends who are part of true believer ghost hunter groups, sometimes it's in response to something broadcast on the news, sometimes it might be a referral from a follower who knows someone with such an experience, sometimes it might be a cold call from someone who saw them on TV. Two of these friends you met a few years ago in episode #668, "A Science Based Ghost Hunting Toolkit," when my friends Ben Radford and Kenny Biddle shared what gear they bring along — and, spoiler alert, it's never the glitzy electronic instruments that TV ghost hunters carry because they think it makes them look sciencey.

To answer today's question, Ben gave me a list of real-world, physical causes for some specific ghost cases that he solved. When we ask what accounts for the experiences people are having if it's not actual ghosts from beyond, consider these possibilities:

• In several instances, security cameras at places like police stations, courthouses, and private businesses captured images of glowing, fuzzy apparitions that many took as ghosts. In each case, Ben proved that it was simply an insect on or near the camera lens, out of focus because of its proximity to the lens, and glowing because the sun was hitting it right or it was illuminated by the camera's lighting.
  
  
• In another case, the glowing ghost appeared only in videos taken at night, only when the moon was visible, and it moved across the driveway very slowly, taking as much time as it took the moon to cross the sky. This ghost was simply the moon reflecting off the tar in an asphalt driveway.
  
  
• A woman took a photo in an allegedly-haunted hotel room, and when she checked the photo, it showed a strange face and arms coming out of a mirror. However, it was simply an artifact of the reflection of her camera flash which dominated the entire photo, leaving plenty of room for perceptual creativity like pareidolia.
  
  
• During a paranormal tour of a museum in England, one visitor's photo captured a very creepy image of a woman's face and partial body in the darkened museum. After much investigation it was found to have simply been one of the other tour guests. One piece of advice Kenny gives is to always take a clear photo of everyone present at such an event, to prevent this kind of confusion.
  
  
• A man who believed his house was haunted was most troubled by somebody tapping on his feet as he slept, even shaking the bed. A diagnosis of Restless Leg Syndrome seemed to get rid of all the ghosts.
  
  
• A hotel had multiple cases of screaming coming from an unoccupied room, which when checked was always found to have been ransacked. With some careful study of the evidence — which was all security camera video in the hotel corridor, showing an alleged security guard checking out the room — it was proven that all the video was faked. The entire thing was hoaxed by a single person.

Hoaxes are, unfortunately, a very real part of the ghost phenomenon. There will always be bad actors trying to get attention or just having a rush. Kenny once filmed a ghost hunting group having a seance inside an allegedly haunted house, and caught the group leader lifting the seance table with his knee — deliberately deceiving his loyal followers. Hoaxing is real, and therefore it does always have to be considered. Ben also investigated a restaurant with a popular reputation for being haunted, and found that the restaurant staff themselves hoaxed everything as a marketing stunt. However, the vast majority of people with ghost experiences are perfectly honest, and genuine in their belief of what they saw.

And really, the things that convince people they've had a ghost experience fall into three broad categories: neurological triggers, perceptual and cognitive errors, and environmental factors.

Neurological triggers

Beginning with sleep paralysis as probably the overall leader, neurological triggers likely explain many of the most dramatic episodes: things like apparitions appearing at your bedside or holding you down so you can't move.

This category is also where we find the two close cousins of sleep paralysis, hypnagogia and hypnopompia. These happen when we are just falling asleep, or just waking up. You might suddenly hear a door close, or someone calling your name, or some other ordinary sound, and it often wakes you up. Being in a relaxed state or reading a book or doing some long repetitive task can also lead to a hypnagogic state where you might suddenly have a visual, auditory, or tactile hallucination, usually mild and usually not frightening.

Hypnopompia, when your body is just starting to wake up, is different. During NREM, often following a dream, a burst of brain activity can trigger a dream state but not quite enough to wake you up. This is when you are susceptible to full sleep paralysis episodes. It can also cause a shocking and frightening sudden end to the dream you were having. It can cause alarming hallucinations of any kind that jolt you awake, leaving you certain that whatever you just experienced was real. There might be an unknown dog in the room. A stranger just rushed down your hall. Someone in your family might have just been killed. The experiences are fleeting, but the impression that it was real can be lasting. Ever had to run to a family member's room to see if they're OK? Thank hypnopompia.

Perceptual and cognitive errors

This is where our brains' nature fails us. A brain is not a digital recorder. It is analog wetware with no digital storage at all. As we perceive the world around us throughout the day, the brain has to take electrical impulses from our eyes and ears and nerves and generate for us a picture that is a full 3D representation of the room. About 1% of our field of vision receives high-detail processing at any moment; the rest is a shortcutted, efficient simulation built from assumptions, patterns, and predictions, much of it being updated only about every 15 seconds or so. Between our brains and our conscious minds is a generated abstraction layer. It is radically imperfect, but it is good enough for us to get around, to find food, to stay safe.

Perceptual errors like confirmation bias, pattern seeking, pareidolia and apophenia — which seem to us like failings — are actually essential tools that our brains need to keep us supplied with a "good enough" world map at every moment. The more sophisticated humans have grown, the more complex our relationship with these tools has become. We know our brains have to use such shortcuts, and we've become increasingly aware that this means we'll get bad information sometimes. Anyone saying "I know what I saw" doesn't understand how brains work. What you know is merely what you think you remember about the abstractions your brain gave you.

And so we see faces where there are none. We see figures that aren't there. In our periphery, constituted from generated slag and old data, a chunk of missing data is interpreted into a recognizable human form and we actually did see a shadow person dart across the ceiling. It wasn't there, but we didn't imagine it either. Pareidolia did its best to give us known images to fill in that blank spot.

And there is the biggest compromise of all: memory. Our memories evolved to be as good as they need to be so we can find food and stay safe — and that's about it. Memory researchers have been able to take advantage of cultural events that had broad impact, such as the O.J. Simpson verdict, the destruction of the space shuttle Challenger, and the 9/11 terror attacks. Thousands of people were questioned about the details of how they heard the news, who they were with, where they were — at intervals of one year, two years, and ten years. Of the major details that people forgot, most were forgotten within the first year. After two years, the rate of forgetting major details slows. By ten years, the brain has formed a stable and consistent picture of what it thinks happened that day — even though 40% of the major details are wrong. Yet confidence in the accuracy of the current version of the memory remains very high for everyone throughout the term. So you and I and anyone else is likely to be very firm about every event we remember — "I know what happened because I was there" — the fact is that we're all wrong about much of it, even though we are absolutely certain.

Memories are good enough to get us through our day. Beyond that, they're garbage. And that's exactly what our brains need them to be, so they can get on with their other work.

Environmental factors

These are the things that people like Ben Radford and Kenny Biddle will often find. A mirror reflecting light in an unexpected way. An imperceptible mechanical vibration that gradually moves an object. A trick of the light. Outside noise reflecting oddly off the neighbor's house and producing a phantom voice. Lens flare reflecting light inside the camera lens and creating an inexplicable image. There are alleged ghost photographs that turn out to be nothing more than a fortuitous alignment of a lamp, a curtain, and a vase that look like a demonic figure — that anyone can swear wasn't there when the photo was taken!

So many physical objects and phenomena can manifest and align and appear in so many ways, and account for many perceived apparitions. But environmental factors also affect the witness's very perception itself. Changing light conditions inducing sensory disorientation. Entering an unfamiliar space, perhaps with very high or very low ceilings, walls that are close or far, temperatures or sound environments that are new; all of these contribute to stress and unease.

Your expectations and things you might have heard about the place, stories of the local ghost from the old days; all of these things have a tangible impact on your state of mind and resulting levels of stress and anxiety.

Stress leads to stress responses, perhaps even as far as the acute stress response, also known as the fight or flight syndrome. Adrenalin. Cortisol. Increased heart rate and blood pressure. Tension and alertness max out. Our brains shift from rational reasoning with the prefrontal cortex to rapid instinctual survival mechanisms with the amygdala. Judgement is impaired. We focus on threats and negative biases. Thoughtful analysis is shelved. Memories formed during this time can be greatly impaired, yet highly vivid at the same time. In short, you act like an idiot, are fearful of everything, and whatever it is you think you remember so well is very probably not what happened at all.

One need only walk into a place that they believe is haunted or that is sufficiently unfamiliar to trigger the beginnings of this syndrome. It need be only a bit of adrenalin, and just a tad of your amygdala hijacking you from your prefrontal cortex. It is a physiological fact that we are likely to make more cognitive and perceptual errors in an environment that's creepy. Evolution did this to us. Those more likely to panic and flee ended up not getting eaten just often enough that they outcompeted the chill people, and it became an evolved trait. In short, we evolved to perceive ghosts and monsters, even where there aren't any.

So here's the bottom line. When someone tells me about their ghost experience and asks me to suggest what it might have been, since I'm claiming there are no such things as ghosts, here is the only honest answer I can give.

• First, we know for a fact that around half of the major details of your experience are remembered wrong. So you are wrong when you describe your experience to me, so there's hardly any point in trying to explain something that didn't happen.
  
  
• Second, you were frightened, and so your amygdala kept you from ever even experiencing the actual event; instead it gave you the greatly abridged fight-or-flight version.
  
  
• Third, given the above, it could have been any of a thousand things. It could have been a neurological trigger, a perceptual or cognitive error, or an actual environmental factor. And if there actually was something there in the environment that caused your experience — well, given the virtually limitless array of "things it could have been" could only be determined by having a skeptical investigator on site.

In short, I don't want to insult you by telling you some explanation that I know is almost certainly wrong. Brains are wild and crazy things.

By Brian Dunning
Follow @BrianDunning