Inattentional blindness vs change blindness


We like to think that we see the world as it is and that our eyes function very much like video cameras recording all the details in our field of vision.

Nothing could be further from the truth. The truth is that sometimes we are unable to see objects that are right in front of us. This, in psychology, is known as inattentional blindness.

Inattentional blindness is the phenomenon of missing objects and events despite them being in our field of vision. It happens because we are not paying attention to these objects and events.

Our attention is directed toward something else. Hence, it is attention that is important for seeing things, and merely looking at them is no guarantee that we’re actually seeing them.

Difference between change blindness and inattentional blindness

There’s this real-life incident of a cop who was chasing a criminal and failed to notice an assault that was happening nearby. The cop completely missed the assault during the chase. He was charged with perjury for claiming that he didn’t see the assault. It was happening right in front of him. In the eyes of the jury, he was lying.

There’s no way he could have missed the assault, but he did. When researchers simulated the incident they found that around half of the people reported not seeing a staged fight.1

Another phenomenon closely related to inattentional blindness is change blindness where you fail to notice changes in your environment because your attention is focused on something else.

A famous experiment involved showing subjects recorded footage of a bunch of players passing basketball amongst themselves. Half the players were wearing black shirts and the other half white shirts.

The participants were asked to count the number of times players with white shirts made passes. As they counted the passes, a person wearing a gorilla suit walked across the stage, stopped at the center, and even thumped their chest looking directly at the camera. 

Nearly half of the participants completely missed the gorilla.2

In the same study, when participants were asked to count the number of passes made by players wearing black shirts, more participants were able to notice the gorilla. Since the color of the gorilla’s suit was similar to the players’ shirt color (black), it was easier to notice the gorilla. 

Further evidence that attention is critical to seeing comes from people who experience brain injuries resulting in lesions in their parietal cortex. This is the area of the brain associated with attention.

If the lesion is on the right of the parietal cortex, they fail to see things on their left and if the lesion is on the left they fail to see things on their right. For example, if the lesion is on the right, they will fail to eat food on the left side of their plates.

Reason for inattentional blindness

Attention is a limited resource. Our brains already utilize 20% of the calories that we consume and were it to process everything it came across in the environment, its energy requirements would be greater.

To be efficient, our brains process limited information from our environments and it also helps to reduce attentional overload. Often, the brain focuses only on those things that are important and relevant to it.

Expectation also plays a big role in inattentional blindness. You don’t expect to see a gorilla in the middle of a basketball match and therefore it is likely that you’ll miss it. Though our mind processes limited amounts of visual information from the environment, it is usually enough to let us form a coherent representation of the external world.

Based on our past experiences, we develop certain expectations of how our environment will look like. These expectations sometimes, though allowing the mind to process things faster, can cause misperceptions.

If you’ve ever proofread, you know how easy it is to miss typos because your mind is keen to finish reading the sentence quickly.

When attention is focused inward

Inattentional blindness not only happens when attention is focused away from the missed object toward something else in the visual field but also when attention is focused on subjective mental states.

For example, if you’re driving and daydreaming about what you’ll eat for dinner, it is likely that you’ll be blind to what’s in front of you on the road. Similarly, if you’re recalling a memory, you might be unable to see things that are right in front of you.

Apollo Robbins starts off this cool video by showing how memory recall can lead to inattentional blindness:

Inattentional blindness: blessing or curse?

It’s easy to see how the ability to focus on a few important things in our environment must have helped our ancestors. They could zero in on predators and prey and choose to focus on mates that interested them. Lacking the ability to ignore unimportant events meant lacking the ability to focus on important ones.

Modern times, however, are different. If you’re living in an average city, you’re constantly bombarded by visual stimuli from all directions. In this chaotic soup of stimuli, the brain sometimes miscalculates what’s important and what’s not.

Also, there are too many important things going on in your environment but your visual system didn’t evolve to deal with all of them at a time. 

For instance, texting while driving may be important for you but so is noticing the motorcycle that is coming crashing towards you. Unfortunately, you can’t attend to both.

Knowing the limits of your attention allows you not to have unrealistic expectations of what you think you can see and take the necessary precautions to avoid accidents caused by inattention.


  1. Chabris, C. F., Weinberger, A., Fontaine, M., & Simons, D. J. (2011). You do not talk about Fight Club if you do not notice Fight Club: Inattentional blindness for a simulated real-world assault. i-Perception2(2), 150-153.
  2. Simons, D. J., & Chabris, C. F. (1999). Gorillas in our midst: Sustained inattentional blindness for dynamic events. Perception28(9), 1059-1074.