Study Highlights That What You Believe Changes What You Perceive

Those who have ever had an eye test will know that many things can affect what a person can see. But new research at Birkbeck, University of London has found that our perceptual sense of clarity and vividness doesn’t just depend on what our eyes can see – but on what our brains believe.

Across three studies, over a hundred people were shown different visual patterns, and could learn to expect that their sensory impressions would probably be clearer or more ambiguous. In different contexts, things could look more vivid or more fuzzy. When participants expected to have a clearer visual impression, they became more confident in what they were seeing and began to say things looked clearer, when in fact the pictures on screen hadn’t actually changed at all.

The study was led by Helen Olawole-Scott, a PhD student, and Dr Daniel Yon, a Lecturer in the Department of Psychological Sciences. Dr Yon commented: “As we go about the world, we usually have a sense of confidence or uncertainty associated with what we are perceiving. We were interested in how our brains work out how much we should trust our senses, and in particular, we wanted to know whether our expectations might trickle into these feelings we have about what we can and can’t perceive.

“The results provide one of the first demonstrations that our subjective sense of clarity or vividness can depend on what we believe, not just on what our eyes see. This will be important for scientists trying to understand how our brains build up our conscious awareness of our surroundings. These results might also eventually be useful in helping us to understand unusual perceptual experiences like hallucinations – where people have a sense that something is vivid and real, even when it isn’t. Understanding how beliefs and experience are linked could also be important for thinking about how our sensory abilities change as we get older, where beliefs about what we can see and hear might not coincide with reality.”