Yale Research Links Visual Processing Deficits to Paranoid Thinking, Study Finds

Our deepest beliefs, like paranoia, might have surprising roots in our most basic senses. A new Yale study suggests this connection, finding that individuals with stronger tendencies toward paranoid thinking (the belief that others intend them harm) and teleological thinking (ascribing excessive meaning and purpose to events) struggled with a simple visual task. When asked to determine if one moving dot was chasing another, these individuals were significantly more likely to confidently misinterpret random motion as a deliberate pursuit.

The findings, published Dec. 17 in the journal Communications Psychology, suggest that, in the future, testing for illnesses like schizophrenia could be done with a simple eye test.

“We’re really interested in how the mind is organized,” said senior author Philip Corlett, an associate professor of psychiatry at Yale School of Medicine and member of the Wu Tsai Institute. “Chasing or other intentional behaviors are what you might think of as experiences perceived at a very high-level in the brain, that someone might have to reason through and deliberate. In this study, we can see them low down in the brain, in vision, which we think is exciting and interesting — and has implications for how those mechanisms might be relevant for schizophrenia.”

Paranoia and teleological thinking are similar in that they are both misattributions of intention, but paranoia is a negative perception while teleological thinking tends to be positive. Both patterns of thinking are linked to psychosis and schizophrenia.

Hallucinations are associated with psychosis as well and are often about other people, said Corlett, suggesting there may be a social component to these visual misperceptions.

“So we wondered whether there might be something related to social perception — or misperception, what we refer to as social hallucination — that we could measure and that relate to these symptoms of psychosis,” he said.

Participants in the study watched moving dots on a screen, some scenarios depicting one dot chasing another, others showing random movement. Their task was simple: determine if a chase was taking place. However, the results revealed a striking difference: those with higher levels of paranoia and teleological thinking (measured through questionnaires) were far more likely to confidently assert that a chase was occurring, even when the dots were moving randomly. In essence, they were seeing social interactions—a chase, a pursuit—where there was only random motion.

In additional experiments, the researchers asked participants to identify which dot was doing the chasing and which dot was being chased. In these results, paranoia and teleological thinking began to diverge.

“People with paranoia were particularly bad at detecting which dot was being chased,” said Santiago Castiello, lead author of the study and a postdoctoral researcher in Corlett’s lab. “And people with high teleology were particularly bad at detecting which dot was doing the chasing.”