Can dogs sense ghosts?

With senses far sharper than ours, dogs detect what we can’t—perhaps more than we realize. -Original article by Clarissa Brincat for Popular Science

Marc Eaton, a professor of sociology at Ripon College remembers talking to a paranormal investigator who had recently lost his father. “His dog would repeatedly bark at the stairs in his home and seemingly follow someone or something up the stairs,” Eaton said. “Given this behavior, the recent death of his father, and the fact that he was already inclined to believe in ghosts, he concluded that his dog was sensing the spirit of his father, and believed that his father was watching over him as he grieved.”

People have long believed in their dog’s ability to sense spirits. In ancient Mexico, the Aztecs believed that dogs could see ghosts and guide their masters’ souls through the underworld. But what do experts make of it?

The psychic perspective

Some parapsychologists, people who study paranormal phenomena, believe the explanation lies in dogs’ extrasensory perception, or ESP—mental abilities beyond the five senses. ESP includes things like telepathy (reading thoughts), clairvoyance (perceiving distant events), and precognition (foreseeing the future). 

“Ghosts aren’t physical phenomena to be picked up by the senses. So some form of non-sensory perception would be needed to perceive a ghost,” says parapsychologist Loyd Auerbach. “Dogs and cats—and likely most animals—are psychic, just like humans.” 

But scientific support for ESP is scarce, and many studies fail to provide conclusive evidence that it exists.

Still, some people argue that ESP operates beyond the limits of conventional science, making it impossible to prove or disprove. That argument could extend to dogs’ ability to sense ghosts, as well. Maybe we just don’t have the tools to accurately measure what dogs sense?

The sensory explanation

Sometimes, however, the reasons dogs and cats seem to be seeing ghosts might be rather mundane. 

“Animals do hear and even see physical things that we cannot,” Auerbach says. “If there is any insect or small animal activity in the walls or at the outer walls, dogs and cats may hear that.” His own cats, he says, sometimes leap at something he can’t see—until he looks closer and finds a tiny insect.  

Psychologist Christopher French, who studies paranormal beliefs and wrote The Science of Weird Shit, agrees with this explanation. “As I’m a skeptic, I don’t believe in the supernatural at all,” he says. “It seems far more likely to me that dogs sometimes react to natural stimuli that humans cannot detect, given their superior sense of smell and hearing.”

Dogs have incredible senses

Dogs have about 220 million scent receptors in their noses, compared to roughly 5 million in humans. They also have a specialized Jacobson’s organ (or vomeronasal organ) that can detect chemical cues beyond normal smell. In the 1950s, scientists at Duke University found that dogs could sniff out garlic oil diluted to 0.00000005 percent with 85 percent accuracy. More recently, a study showed that dogs can use their sense of smell to pick out blood samples from people with cancer with almost 97 percent accuracy. Another study found that dogs can smell human stress.

Their hearing is equally impressive. Dogs can hear sounds that are both much higher in pitch (up to 65,000 Hertz) and much quieter (as low as -15 decibels) than humans can, giving them extraordinary sensitivity to noises completely beyond our range. 

These super senses may explain why dogs appear to see things we humans don’t. “Maybe, instead of seeing something spooky, they are orienting their heads to smells and sounds to help them perceive these stimuli better,” says Ellen Furlong, a psychology professor at Transylvania University who studies animal cognition.

Dogs’ vision, on the other hand, is generally worse than ours. “Humans can see more clearly for a farther distance than dogs can and can see a wider range of colors—dogs are red/green color blind,” says Furlong. 

However, they’re better at picking up fast-moving objects and subtle changes in light. For example, a TV screen that looks smooth to us might seem to flicker to a dog, Furlong explains. So when dogs seem to react to something invisible, they might actually be picking up on tiny movements or light changes that our eyes simply can’t detect.