At Halloween, when people share tales of haunted houses, ghosts in the graveyard and things that go bump in the night, Wake Forest University psychologist Melissa Maffeo responds with science.

Author of the 2025 book “Science of the Supernatural: Critical Thinking for the Mind and Brain,” Maffeo explores the spooky experiences pop culture often attributes to the paranormal through the lens of neuroscience. She says several key neurological and psychological factors can explain why we see ghosts.

“When we experience some kind of ambiguous sensory information, maybe a sound that is very difficult to hear or a light that we can’t quite find a source for, our brain wants to make a story out of it,” says Maffeo, a teaching professor of psychology.

Her work bridges the gap between ghost stories and the realities of human perception. She co-founded the Neuroscience Teaching Conference and has earned multiple awards for teaching innovation and excellence at Wake Forest.

What was the inspiration for your book, “The Science of the Supernatural”? How did a psychologist end up studying ghosts?

The inspiration came from my love of ghost stories and horror movies, and also my love of neuroscience and psychology. As I got older, I started studying the brain and behavior, and I really wanted to marry these two fields. Why do people interpret an experience as supernatural when other people might not interpret the experience as supernatural? Why do so many people believe in ghosts? These are the questions I wanted to investigate by writing the book.

In psychology, we talk about sensation—how the outside world interacts with our body—and perception, which is what our brain tells us about that thing. I became interested in how physical things in the world might give a person a perception of something paranormal. And then taken a step further, one person might experience something and strongly believe that it’s a ghost that they’re experiencing, and another person might experience the exact same thing and have no paranormal explanations attributed to it. I was really interested in digging into the research to find out how our brain interprets ambiguous sensory information and sometimes turns it into something paranormal.

How can science explain ghost sightings?

Science can explain them through a number of different ways, both with psychology and neuroscience. One is this idea that our ears are only capable of picking up a small percentage of the sound waves that are out there in the world. So, if there’s a sound that is too low frequency for my ears to be able to detect it, that sound essentially doesn’t exist to my brain. There have been a number of anecdotal instances where people have been exposed to these low-frequency sound waves that are below our threshold for hearing and didn’t notice a sound, but noticed a weird feeling and often interpreted that as a ghost.

When we sleep, our brain cycles through different stages, and one of the stages is called REM sleep. This is also typically when we have our most vivid dreams. Possibly because of that, our brain actually paralyzes our body when we’re in REM sleep. Roughly 20% of the population globally experiences sleep paralysis. When people wake up during REM sleep, they might find that their body is still paralyzed. They might find that they are not interpreting sensory signals coming from their body. They’re not responding to motor signals that they’re sending to their body and their dreams are spilling out into their wakefulness. They feel like they’re still awake, but their brain is very much still dreaming. And during that time, many, many people report having visions of figures in their room, strange lights, unexplained buzzing sounds, sometimes levitation, sometimes out-of-body experiences.

Can you talk about the neuroscience of fear? What is happening in the brain?

Sensory information goes to an almond-shaped structure that’s right behind our ears called the amygdala, and our amygdala processes what we think of as fear, but really it’s a detection of threat, and then the rest of our brain interprets it as the feeling of something that’s scary. 

One thing that we’re beginning to understand about the human mind is that our brains are constructed to create stories even out of things that might be ambiguous. So when we experience some kind of ambiguous sensory information, maybe a sound that is very difficult to hear or a light that we can’t quite find a source for, our brain wants to make a story out of it because we are naturally averse to ambiguity. Maybe I hear a twig snapping behind me and I don’t know what the source of that sound is. The fear circuitry in my brain is going to put me on alert and say, “This could potentially be something dangerous.” The rest of my brain, my newer brain areas, my cortex, my frontal lobe is going to start making a story out of that.

Ghost hunters often use EMF meters to detect spirits. Is there any scientific validity to these measurements?

Measurement instruments need reliability—measuring something the same way every time—and validity, meaning they actually measure what we think they are measuring. Handheld electromagnetic activity detectors reliably measure electromagnetic fields and currents, but whether they validly detect the presence of the paranormal remains to be seen.

Some people may simply be more sensitive to electromagnetic fluctuations, and because we like to make stories out of our experiences, they interpret those physical sensations as something paranormal.

What do you hope people take away from your research into the supernatural?

I’m not here to debunk anyone’s experiences. I simply want to cast light on alternative explanations for those experiences. Ultimately, paranormal experiences usually stem from a convergence or “perfect storm” of environmental, neurological, and psychological factors. One of the biggest predictors of whether a person will have a paranormal experience is whether they believe in the paranormal. 

Why are we interested in ghosts? I think it’s because we want to believe that there’s something else out there.

Learn more

See the On Topic page to hear more Wake Forest University experts discuss relevant topics and new research.