Most people expect that they can see things with peripheral vision, but a new study demonstrates that we are not seeing what we think we are. The Uniformity Illusion: Central Stimuli Can Determine Peripheral Perception found that what we see in the center of vision is far more accurate than vision in the periphery, (which we would expect) but also that our brain is filling in the picture. The website for the Association for Psychological Science quotes one of the authors:
“Our findings show that, under the right circumstances, a large part of the periphery may become a visual illusion,” says psychology researcher Marte Otten from the University of Amsterdam, lead author on the new research. “This effect seems to hold for many basic visual features, indicating that this ‘filling in’ is a general, and fundamental, perceptual mechanism.”
That would be interesting on its own, but urban studies PhD candidate Tara Goddard had an insight:
Indeed, it would explain a lot about why people get hit by cars where claims that he or she just didn’t see the person there; it may well be true.
The researchers looked at all kinds of images, changing the shape, orientation, luminance, shade, or motion.
The results showed that all of these characteristics were vulnerable to a uniformity illusion – that is, participants incorrectly reported seeing a uniform image when the center and periphery were actually different.
You can try it yourself at Uniformity Illusion; I did and it is really true, the shapes on the periphery do begin to look like the shapes in the middle. The brain changes the picture. So if a cyclist is at the side of the road in peripheral vision, the brain just might erase him, particularly if it is dark and rainy.
This study might have implications for road safety, and provides more ammunition to those pushing for separate protected bike lanes. The researcher calls the illusion “a fun thing” but the implications are serious:
As we go about daily life, we generally operate under the assumption that our perception of the world directly and accurately represents the outside world. But visual illusions of various kinds show us that this isn’t always the case. As the brain processes incoming information about an external stimulus, we come to learn, it creates a representation of the outside world that can diverge from reality in noticeable ways.
I know that a lot of drivers would like cyclists to disappear, but in fact it might actually happen.