Watch CBSN Live

What You See Depends on What You Look For

Most people like to think of themselves as alert and aware. But under the right circumstances, even the most observant people can be blind to what's going on around them.

In part III of the "Train Your Brain" series, Tracy Smith looks at what is called inattentional blindness. And it means that people really can miss things--big things--that happen right before their eyes. A team of Harvard psychologists came up with a way to study the phenomenon using the videotape that you're about to see.

Take a look at this tape. The object is to count the number of times the people in white shirts pass the ball. Remember, people in white shirts only. Notice anything unusual? If you didn't, you're not alone.

"About 50% of the time people don't notice that a person in a gorilla suit has walked through the display, through the players, and out the other side," says Dan Simons, assistant professor of psychology at Harvard University in Boston. "Even if it stops and thumps its chest."

Simons and his colleague, Christopher Shabree, made the tape and found that half the people who watched it didn't even suspect anything unusual.

"I'd say, 'Did you notice anything walking across the screen?' No. 'Did you notice the gorilla?' What? The typical reaction of many people is, 'I missed that?'"

The bottom line is this: if you are not expecting to see something--you may not. The intuition is that if something unusual happens in a scene, it will grab your attention. It'll make you pay attention to it. And the reality is that if you're not expecting something, quite often you won't see it at all.

One of the most likely places for inattentional blindness to show up is on the road. "Driving is a very effortful thing to do," says Simons. "When we heard about some guy plowing into someone and turning to the police officer and saying I didn't even see him--is that guy lying? He might well not be. Even though this person was completely visible."

Now, you can't really train your brain to expect the unexpected, but Simons says there are things you can do to avoid an accident--like staying off the cell phone. "If you combine having a conversation with driving a car, both of which are very attention demanding, it makes you even that much less likely to notice unexpected events," says Simons.

And it doesn't seem to matter if the phone is hands-on or hands-off: The very act of holding a conversation is enough to distract you. The same thing applies for people doing things besides driving--like watching kids on a playground. If you're talking to someone else or reading, you may not see trouble coming. Just because something is visible in front of you doesn't mean you're going to notice it.

Now, if you missed the gorilla, it doesn't mean you're stupid. The researchers said they found no correlation between intelligence and inattentional blindness. In fact, it might mean that you're more focused. As Simons said, there's no way to train your braito expect the unexpected, but just being aware of the phenomenon can help.
©MMII CBS Worldwide Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed

View CBS News In
CBS News App Open
Chrome Safari Continue