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What Is Perception Blindness?

Jennifer Long
Jennifer Long

Perception blindness, also called perceptual blindness or inattentional blindness, is a type of visual perception. It is a phenomenon in which people cannot see things in plain sight. The brain controls what is processed even though the eyes see the information. There are four factors that determine which visual information is processed by the brain and which information is discarded — conspicuity, workload, expectation, and capacity — and imbalance in any one of these can lead to perceptual blindness.

The senses of the human body are constantly gathering information. Unfortunately, not all of this information is processed for perception. This is because, although there is not a limit on incoming information, there is a limit on what the brain can process. For this reason, the brain uses four factors to determine which information gets processed. Perception blindness is likely to occur when any one of these factors is unbalanced.

Multitasking may cause people to overlook certain information.
Multitasking may cause people to overlook certain information.

Conspicuity is the first factor that influences perception. Sensory conspicuity is the brain's way of perceiving things based on colors and shapes, while cognitive conspicuity is the amount of relevance the brain gives to visual information. Both of these aspects can be manipulated by the brain. Certain information from the background can be discarded if it does not fit with the brain's goals of sensory or cognitive conspicuity, such as a specific flag blowing among several others or a person wearing a black shirt among many people wearing black and white shirts. These are instances of perception blindness.

Workload relates to the brain's workload. Perception blindness will occur more frequently while the brain is also trying to perform other tasks. Multitasking is common for many people, but performing two of the same types of perception tasks can reduce the amount of attention the brain provides. Two visual tasks, such as watching a bicyclist ride by and watching crosswalk signs, can cause a larger workload for the brain, which can lead to missing pieces of information.

Expectation and capacity are the final two factors that can influence perception blindness. People expect things to look a certain way, particularly if they have been the same for a while. If something changes, those objects can be overlooked. Capacity is the amount of attention each person can devote, and it varies depending on each person's mental ability to learn.

Preventing perception blindness involves multiple steps and a bit of time. Distractions from the task at hand should be minimized. Focusing on specific tasks one at a time should be practiced. Large tasks can be broken down into smaller ones. When working on long tasks, short breaks can help regroup thoughts and allow the brain a few minutes to rest.

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Discussion Comments


@bear78-- I agree with you. I think part of the problem is also not being present. Most of us look around us without really seeing or understanding much. We have so many thoughts in our head and it takes up all of our attention. The brain unfortunately doesn't have a limitless capacity. There is only so much it can do at once.


@ysmina- You do realize that perception blindness happens to everyone right? It's not just you and it has to do with your brain being overloaded with information.

The next time it happens, ask yourself if you have a lot on your mind or if you are trying to do two things at once. More than likely, you are. It is really multi-tasking that causes perception blindness. Multi-tasking has become a desirable characteristic now and people proudly claim it on job applications. But multi-tasking just means that the brain is switching between different information quickly, and not focusing well enough on either.

That's why we see but don't really see at times.


I experience this all the time. For example, I will be looking for something in my room and even though it is in front of me all the time, I don't see it until much later. In fact, everyone in my family knows that I tend to do this and they joke about it sometimes. They say I am a blind who can see.

I guess there is an issue with my brain processing. I wish I knew how to fix it.

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    • Multitasking may cause people to overlook certain information.
      By: apops
      Multitasking may cause people to overlook certain information.