Recently, in Bend, Oregon, a group five unrelated people were hospitalized for hallucinations. In the early hours of the morning, a caretaker of a 78-year-old woman called the police complaining that her vehicle was being vandalized. The officers showed up, saw no suspicious activity and went on their way. At 5:30 a.m., the police were again called and again found no evidence to support the woman's claim. The officers decided she must have been experiencing hallucinations and brought her to a hospital.

The caretaker was ruled healthy and was discharged, but the story doesn't end there. Throughout the day, all five people who had come into contact with the woman began to experience similar symptoms and were hospitalized: The 78-year-old woman, the two officers who came to the scene and a member of the hospital staff. We don't know what caused the hallucinations, but there a number of possible causes.

Some causes of hallucinations include general psychosis, the ingestion of psychedelic drugs, migraines or epilepsy. As far as the situation in Bend, Oregon, it’s possible that the area could have been host to some sort of contaminant like mushroom spores, according to Popular Science, who reported the story. (However, when a hazmat team came to examine the area, no such contaminant was found.)

Sometimes a group of people might experience what’s called the "campfire effect." This is when a person "hears a bump in the night, and everyone around the fire is on edge, sure that every squirrel is Sasquatch," says Popular Science. It might not be fair to label all five individuals as paranoid or crazy, and James Giordano of Georgetown University's department of neurology and biochemistry told Popular Science that it’s most likely the hazmat team missed some sort of contaminant that was present.

Regardless of what caused these hallucinations, it turns out that hallucinatory experiences aren't solely confined to the psychotic, those who have taken psychedelic drugs or those who have been exposed to any other contaminant. Recent studies by researchers at Cardiff University and University of Cambridge suggest we are all hallucinating all of the time to comprehend the world that surrounds us. This research opens new doors of perception as related to the ways we view hallucinations and their prevalence.

Sifting through the noise

One way to look at hallucinations is seeing them as a part of predictive brain processes. We constantly need to make sense of our surrounding world. In trying to grasp a spatial and visual sense of our surroundings that might appear slightly vague when we're barraged by a wide array of sensory input, we have to use our brains to predict and understand the overall structure of the environment with the use of prior knowledge. The prior knowledge we have about an environment plays a huge role in the way we visually process our world.

"Vision is a constructive process — in other words, our brain makes up the world that we 'see'," and "fills in the blanks, ignoring the things that don't quite fit, and presents to us an image of the world that has been edited and made to fit with what we expect," explains lead researcher Christoph Teufel of Cardiff University.

Our predictive brains are beneficial to us because "it makes us efficient and adept at creating a coherent picture of an ambiguous and complex world,” and that it “means that we are not very far away from perceiving things that aren’t actually there, which is the definition of a hallucination,” says Paul Fletcher, senior author of the research done at Cambridge.

No 'broken' brains

To explore these theories of everyday hallucinations, researchers at Cambridge examined 18 people who showed early onsets of psychosis and 16 people who are considered to be mentally sound. The participants were asked to look at a series of incomplete black and white images. Some of these images contained a person while other images did not. The individuals were asked to identify whether or not the images depicted had a person, but many found it difficult to do so based on the ambiguity of the images.

The participants were then shown a series of color images, some of which were colored versions of the original black and white images. Researchers found that the individuals who were prone to hallucinations were better able to identify whether or not the original black and white images depicted a person once they were again shown the original images. The researchers later asked a group of 40 mentally healthy individuals to perform the same exercise and found that they also had difficulty in clearly identifying the content of the images. The researchers feel that psychosis-prone individuals might be using the predictive aspects of their brain to a greater degree, as they might be predicting visuals that aren’t actually present in the outside world.

Naresh Subramaniam of the Department of Psychiatry at Cambridge says these findings show us that "these symptoms and experiences do not reflect a 'broken' brain but rather one that is striving — in a very natural way — to make sense of incoming data that are ambiguous."

We have no definite answers for the eerie situation in Bend, Oregon. What we do know, though, is that hallucinations are completely natural and happening all the time, whether we "see" them or not.