Inattentional Blindness in Psychology

It's logical to think that you see whenever your eyes are open. But the reality is that attention plays a major role in visual perception.

One of the primary reasons why you may fail to notice things like obvious bloopers in movies, for example, is a psychological phenomenon known as inattentional blindness. When you focus hard on one thing, such as the actions of the main character in a film, you might not notice unexpected things entering your visual field.

What Is Inattentional Blindness?

The term "inattentional blindness" was first coined by psychologists Arien Mack, PhD, and Irvin Rock, PhD, who observed the phenomenon during their perception and attention experiments.

"Because this inability to perceive, this sighted blindness, seemed to be caused by the fact that subjects were not attending to the stimulus but instead were attending to something else…we labeled this phenomenon inattentional blindness (IB)," they explained in their book "Inattentional Blindness."

One of the best-known experiments demonstrating inattentional blindness is the "invisible gorilla test" carried out by Christopher Chabris, PhD, and Daniel Simons, PhD. In this experiment, researchers asked participants to watch a video of people tossing a basketball, and the observers were told to count the number of passes or to keep track of the number of throws versus bounce passes.

Afterward, the participants were asked if they had noticed anything unusual while watching the video. Across all the tests, approximately 50% of the participants reported seeing nothing out of the ordinary.

But in reality, something odd had happened. In some instances, a woman dressed in a gorilla suit strolled through the scene, turned to the camera, thumped her chest, and walked away. While it may seem impossible that the participants missed such a sight since their attention was focused elsewhere and on a demanding task, the gorilla basically became invisible.

Why It Occurs

Rather than focusing on every tiny detail in the world around us, we tend to concentrate on things that are most important, relying on our existing schemas to "fill in the blanks." This approach is highly economical.

One of the reasons why people so often "miss the gorilla," so to speak, is simply because the stimulus does not fit into their idea of what a basketball game is supposed to look like. A gorilla showing up in the middle of a basketball game is unlikely to happen in a real-world setting, so we are less likely to notice it. It is essentially ruled out as a component that will help you better understand or carry out the task at hand.

That said, while we do sometimes fail to miss things in the world around us, we are generally pretty good at noticing information that is relevant to us, such as a car speeding toward us or a deer jumping out of the trees into the road. Of course, this is not always the case.

Factors

There are certain factors that can affect inattentional blindness. In the original invisible gorilla experiment, the participants had to count the number of passes made by either the team in black or the team in white.

Out of the participants who were counting passes made by the white team, only 42% saw the gorilla, but for the participants who counted passes made by the black team, 83% saw the gorilla—who was also dressed in black, illustrating the impact of similarity between the unexpected stimulus (gorilla) and task-relevant stimuli (members of the black team).

Examples

We all experience inattentional blindness from time to time, such as in these potential situations:

• Even though you think you are paying attention to the road, you fail to notice a car swerve into your lane of traffic, resulting in a traffic accident.
• You are watching a historical film set in ancient Greece. You don't notice a major blooper in which an airplane appears in the background of a pivotal scene.
• You decide to make a phone call while driving through busy traffic. You fail to notice that the traffic light has turned red, so you run the stop light and end up getting a traffic ticket.
• While playing a video game, you are so intently focused on spotting a specific type of "bad guy" that you miss another threat to your character and end up losing the game.

A Word From Verywell

Though it is not possible to avoid all instances of inattentional blindness, it's important to remember this very natural occurrence—particularly when you are in a disagreement with someone about the full scope of a situation.

Your brain is sophisticated enough to help you register and interpret visual cues that it thinks will provide you with the most value. But, in its efforts, visual information—both important and not—can sometimes get overlooked.