Mental Health

Déjà Vu: Feelings of Premonition Are Memory-Based Illusions

Most of us have experienced the odd feeling of déjà vu, often regarded as a supernatural force or a glitch in the matrix. You may perform an action and suddenly feel as though you have done it in that exact specific manner some time in your life. The feeling may even be triggered by a place or by spoken words, leaving some with the feeling they could recognize or predict what happens next.

Déjà vu usually strikes without warning. But researchers from Colorado State University (CSU) have developed a technique to induce the feeling by using dynamic video sequences, building on previous experiment methods.  

Anne Cleary, a cognitive psychologist and professor of psychology at CSU, has studied déjà vu for years. She grew interested in exploring the phenomenon ever since she read Alan S. Brown's book “The Déjà Vu Experience.” Cleary led the new study, which was co-authored by former graduate student Alexander Claxton.

"My working hypothesis is that déjà vu is a particular manifestation of familiarity," said Cleary. "You have familiarity in a situation when you feel you shouldn't have it, and that's why it's so jarring, so striking."

Participants were led through virtual reality scenes such as a junkyard or a hedge garden, which shared slight spatial similarities but were thematically unrelated. Though they could not "consciously remember the prior scene," Cleary said, the participants brain picked up on it and recognized “the similarity.”

The results showed déjà vu "did not lead to above-chance ability to predict the next turn in a navigational path resembling a previously experienced but unrecalled path," although participants did report "increased feelings of knowing the direction of the next turn."

More than 10 years ago, she began publicizing her findings that déjà vu was a memory phenomenon, which attracted counterstatements from around the world, claiming her studies were wrong as people were able to predict the future. Cleary wanted to logically dissect the phenomenon to argue against these claims. 

A study from the 1950s by neurologist Wilder Penfield, which linked familiarity and premonition, inspired her hypothesis: “If déjà vu is a memory phenomenon, is the feeling of prediction also a memory phenomenon?”

Cleary and her team concluded déjà vu does not predict the future but makes people believe they can. It has been noted as a "metamemory" phenomena (another example of which is the "tip of the tongue" sensation when we can't recall a word), reflecting a subjective awareness of unspecific memories.

"I think the reason people come up with psychic theories about déjà vu is that they are these mysterious, subjective experiences," she explained. 

Follow-up experiments are now being conducted by the team to look deeper into the main cause behind the feeling of prediction. The studies hope to address whether it's the familiarity process that drives the feeling, or hindsight bias where people feel convinced they knew what was going to happen after it happens.