Your brain can only process so much visual information at once. Change blindness is a situation in which something you see changes in some way, yet you don’t notice that change.

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The world is full of images and objects that are perceived by your eyes and given meaning in your brain. Sometimes these visual images may change in some way but you may not notice it after some interruption, like a blink. When this happens, it’s called change blindness.

This situation is relatively common and not necessarily harmful. But change blindness can sometimes lead to accidents and other risks. Here’s more about what change blindness is, what causes it, and why it’s an important situation to recognize.

Change blindness is a visual phenomenon in which the thing a person is looking at undergoes some type of change that’s not noticed by that person. This can happen whether a person is looking at an image on a screen, like a television or a smartphone, or with visual stimuli in a person’s surrounding environment.

The American Psychological Association defines change blindness as a failure to see changes in your visual environment after some type of interruption. For example, a person may be driving down the road and blink. After blinking, they may not have noticed that something ahead of them — like a traffic light or sign — has changed.

Interestingly, some of your favorite magic tricks may rely on change blindness. The magician may employ different tactics to divert your eyes and have something appear that you didn’t previously see.

There are various explanations for why change blindness happens. Overall, it may have much to do with your visual attention. If your attention is diverted from an object or image in a certain situation, they you experience change blindness.

This phenomenon may also result from your brain’s inability to encode visual information into short-term working memory, which is part of the executive functioning of your brain. Instead, if the visual information in question isn’t as relevant as the task at hand, change blindness may occur.

In one study on construction workers, researchers discovered that the importance of different visual information may contribute to change blindness. For example, they showed the workers images and asked them to note the differences.

Changes to things that affect someone’s safety (like ladder hazards) were the most noticed. Workers with the most experience tended to notice the most changes compared with the less experienced workers.

The primary symptom of change blindness is not noticing something has changed in the visual environment after some type of interruption.

The interruptions that lead to change blindness may include:

  • blinking or saccades (quickly moving your eyes from one object to another)
  • an object or other obstruction that blocks your visual environment
  • very slow changes to your visual environment

Change blindness may be more noticeable for people who have cognitive issues that affect their working memory. This may include people with dementia, attention deficit hyperactivity disorder (ADHD), people under the influence of drugs or alcohol, or people who haven’t had adequate sleep.

Change blindness isn’t a medical condition that doctors diagnose. Instead, it’s a visual phenomenon that people experience in everyday life to different degrees.

You may experience change blindness firsthand through visual tests where you’re asked to look at one image or video. Then some type of interruption (blank screen) may be introduced, after which a similar but changed image is presented.

You may either see or not see a change between the two images or videos, demonstrating your degree of change blindness.

There’s no standard treatment for change blindness. Furthermore, there likely is no cure for this phenomenon. Research indicates that change blindness boils down to a person’s attention span, which can be highly individual and influenced by various factors.

Along with being aware that change blindness can happen, you may lower your risk of accidents by avoiding things (drugs, alcohol, too little sleep) that may affect your working memory. Avoiding unnecessary distractions from your visual environment (for example, using your cell phone while driving) may also help.

Change blindness becomes particularly important to recognize in situations that rely on a keen perception of the visual world. People in certain jobs, like air traffic controllers, may risk accidents if they experience change blindness when monitoring takeoffs and landings.

Likewise, change blindness may be a risk while driving a vehicle. If you fail to see some change in the road up ahead, you may be involved in an accident that could be life threatening.

Change blindness may also have consequences with eyewitness accounts. What somebody sees (or doesn’t see) can carry a lot of weight, particularly in court situations.

Again, change blindness isn’t a medical condition that a person receives a diagnosis of. It’s something anyone can experience from time to time to different degrees.

The outlook for someone with change blindness is individual and depends on a person’s attention span, different health conditions that may affect their working memory, and lifestyle factors that may also lead to distraction or inattention.

Does change blindness increase with age?

It may. Researchers explain that change blindness tends to be more notable in people with cognitive impairment, such as older people with dementia.

What is an example of change blindness?

NOVA Public Broadcasting Service (PBS) conducted an informal experiment where a person asked a stranger on the street for directions. They sent in a group of people carrying a large board between them and switched out the person who was asking for directions. Only around half of people noticed the person had changed.

Why is change blindness important?

It’s important to understand what change blindness is because it can affect your everyday life. While some of these effects may not have serious consequences, others may increase the risk of accidents or other situations (wrongful convictions).

Speak with a doctor or healthcare professional if you feel change blindness is affecting your everyday life. Sometimes it may be a symptom of a broader health issue, like dementia or lack of sleep. Otherwise, try your best to cut out distractions when you’re performing essential tasks, like driving or working.