Human eyes really play ‘tricks’ on the mind, experts say

The research findings could have implications for many aspects of daily life, including driving, how eyewitness accounts are treated in the criminal justice system, and safety issues such as drone sightings.

The research team from York University and Aston University presented participants with full-scale photographs of railway scenes, which had the top and bottom parts of the image blurred, as well as photographs of small-scale model railways that did not they were blurry.

Participants were asked to compare each image and decide which was the “real” large-scale railway scene. The results were that the participants perceived the blurred real trains to be smaller than the models.

Dr Daniel Baker, from York University’s Department of Psychology, said: “In order for us to determine the true size of objects we see around us, our visual system needs to estimate the distance to the object.

“To get to an understanding of absolute size, you can take into account the parts of the image that are blurry, a bit like the blurry areas a camera produces, which involves a bit of complicated math to give the brain the knowledge of the spatial scale.

“This new study, however, shows that we can be misled in our estimates of the size of objects. Photographers take advantage of this by using a technique called ’tilt-shift miniaturization,’ which can make objects appear life-size. scale models”.

The findings demonstrate that the human visual system is highly flexible, sometimes capable of accurate size perception by exploiting what is known as ‘defocus blur’, but at other times subject to other influences and failing to make sense. to the size of real world objects. .

Professor Tim Meese, from Aston University, said: “Our results indicate that human vision can exploit defocus blur to infer perceptual scale, but it does so in crude ways.

“Overall, our findings provide new insights into the computational mechanisms used by the human brain in perceptual judgments about the relationship between ourselves and the external world.”