You’re walking down a busy street when you zoom past someone as they grab on to your arm saying, “Hey, how are you?” You focus and realize it’s a close co-worker who you’ve been working with almost every day for the past five years. So how is it you didn’t recognize them as they walked in the opposite direction towards you?
This is called visual crowding. Walking on a busy sidewalk, walking past dozens of faces, signs, lights, stores, etc., are all things that command your attention, causing a sensory overload. Your eyes and brain can’t focus on everything at once, thus limiting your visual recognition. Though visual crowding has been studied extensively, its roots remain unclear.
What is Visual Crowding?
To start, let’s find out what visual crowding is exactly. Affecting mostly your periphery, visual crowding impedes your ability to recognize certain objects when they are surrounded by other objects. This lack of recognition ability has less to do with visual acuity and more with how our periphery perceives objects.
For our periphery to properly recognize objects, they need to have the critical distance between them. Take Where’s Waldo? for example. The reason Waldo is sometimes excruciatingly difficult to find is because of crowding. Take away all the other characters, objects, buildings from the picture and Waldo becomes incredibly easy to find.
Sure, without the clutter, anything would be easy to find but that isn’t the way our eyes work. If there’s clutter or crowding, our eyes don’t work to declutter the images being sent to the brain. Instead, the image becomes a blob of unrecognizable colors. Our eyes work hard to recognize objects; harder than most of us probably realize.
How the Brain Recognizes Familiar Objects
Say someone was to place a table in the middle of the road and you drove up to it. You would immediately recognize it as a table even if it is placed in a setting it isn’t meant to be in. The reason we’re able to identify things regardless of their context is thanks to our brain.
Our brain can recognize objects quickly due to the invariances we develop. Continuing with the table example, we know that tables (for the most part) need four legs and a flat surface or top. The table’s shape and inherent features is what makes it recognizable. These are the invariables because they never change making it easier for the brain to recognize it.
Herman Bouma, a vision researcher had done extensive research on the subject of visual crowding and made such an impact that a law was named after him: Bouma’s Law. This law is complicated and has many parts to it. We won’t bore you with pages and pages of academic research, so for our purposes, we’ll keep it simple. But if you are interested in learning more have a look at this article, which goes deeper into understanding Bouma’s Law.
In short, Bouma’s Law aims to explain why our periphery is unable to recognize objects’ features. The bottom line is everything is just too close. The critical distance we mentioned before falls under this law. Objects need a certain distance between them to be recognizable. When the distance is either not there, or not being perceived by the eye, then we get skewed images that don’t make sense to the brain.
Though the distance between objects is the same whether we see it with our peripheral vision or central vision, the clearness of our central vision helps distinguish the objects. However visual crowding can also affect central vision in certain cases.
For example, you walk into an over-stocked discount store where a mess of people are rummaging through bins and bins of clothes. You know from experience that there are clothes in the bin, but when you look inside all you can manage to see is fabric and not the individual clothing items. It isn’t called critical distance for nothing.
Bouma is also a term used in the study of typography to describe a cluster of letters. Some typographers believe that when we read, we are actually deciphering Boumas instead of the individual letters that make up a word. That is to say that we read the shape of the words as a way to more efficiently read. Children often sound out words because they are not used to the shape of words, but as we read more and more, we become more familiar with the features of certain words.
Varying Effects of Visual Crowding
We are all affected by visual crowding. The degree of its consequences may vary in certain people (for example, those with age-related macular degeneration may experience heightened effects of visual crowding as they rely on their peripheral vision), but there is a way to train your eyes.
The key is to have a sharp sense of perception. A recent study has found visual crowding to be linked to the speed in which our brain processes images from the retina and thus suggests eye exercises relating to speed.
Because so little has been proven about theories surrounding visual crowding, it’s hard to truly understand what causes it and why. It is an ongoing debate in the vision research community, with constant development. Hopefully new studies being conducted can soon give us some more insight into the mysteries behind our eyes.