As we glance around the room, we believe we’re seeing everything in sharp focus, but a new study published in the Journal of Experimental Psychology says it’s all just a show our brain puts on for us. Researchers from Bielefeld University studied the precision of our brains by how it sees the outside world and found it’s been fooling us this whole time.
"In our study we are dealing with the question of why we believe that we see the world uniformly detailed," said the study’s coauthor Dr. Arvid Herwig from the Neuro-Cognitive Psychology research group of the Faculty of Psychology and Sports Science, in a press release. "The experiments show that our perception depends in large measure on stored visual experiences in our memory."
The only part of the eye that can actually see an object with precision is the fovea, a thumbtack size magnifying glass in the center of the retina. Most of the time we’re seeing objects out of focus with the rest of the retina, which has a coarse and less-clear focus of the world around us. We get the impression we can see large parts of our surroundings in sharp detail when in reality it’s only a fragment. How are our eyes creating this illusion of sharp focus? It’s our brain.
Over the course of our lifetime we see millions of objects, and one by one, our fovea gets the chance to focus on them. We collect a catalogue of in-focus images into our memory, such as an apple. When an apple is seen through the coarse, less clear part of our eye it’s actually a blurred image. However, it connects to our brain as an apple, and the memory of seeing it in focus through the fovea fills in the blurry details for us. The brain then projects an in-focus apple from the memory center to replace the blurry apple, so we think we’re seeing it clearly out of our peripheral vision.
Researchers studied the strength of our fovea and compared it to the rest of the retina using eye-tracking techniques. In the experiment, they watched participants' eyes with a camera capable of recording 1,000 images per second. As their eyes made quick movements, known as saccades, the researchers quickly changed objects in their field of view. As these objects changed the participants were asked to describe the them as they stood in their peripheral vision — they found that the descriptions were largely based on previous notions of what they could be, kind of like a template for the object from our memory, confirming our brains trickery every time we look around the room.
The brain is tricking us all of the time! Past brain-imaging research has shown that the same part of our brain that senses physical pain also senses emotional pain. When we say you hurt our feelings, it’s both a physical and emotional experience for our brain, giving a whole new meaning to the phrase “heart broken.”
We also experience mental illusions, such as the illusion of memory, which is when our memories are born from embellished stories, dreams, or ideals of what might have been. If the brain fabricates a story about catching a 40-inch fish to impress others on the fishing boat, when the fish was actually 25 inches, the brain may actually trick itself into believing its own lie. This also happens with the illusion of knowledge, which happens when we think we know more about something than we actually do. The illusion of confidence is perhaps the most dangerous of all the brain's facades, because it tricks a person into thinking they're stronger, smarter, or invincible, and may lead them into careless delusions.
It may sound as if the brain is creating a world of delusions right in front of our flawed eyes, but it’s just a means of compensating for the flaws of the human body. While we are not seeing the actual world for what it is, it’s incredible our brain has the ability to replace our visual limitations with memories or predictions of the world around us.
Source: Herwig A, Schneider WX. Predicting object features across saccades: Evidence from object recognition and visual search. Journal of Experimental Psychology: General. 2014.