Are You Paying Attention?


Some researchers suggest that your attention
span may be as short as 8 seconds. Um… try testing it with this exercise. You
have to focus on how many times the players wearing white pass the ball. You may have noticed the white team passed
the ball 16 times. You also may have noticed this gorilla walking through the game, especially
if you’ve seen this video before. But if you were watching the gorilla, and
the white team, you may not have noticed the background changing colour or one of the players
on the black team leaving. This experiment, called “The Monkey Business
Illusion”, was popularised by two Harvard researchers in 1999. It’s based on a similar
1975 study where a women with a white umbrella walks through a basketball game. The invisible
gorilla researchers found about half of those who watched their video for the first time
missed the gorilla. It’s called “inattentional blindness”,
where you fail to notice an unexpected stimulus that is right in front of your eyes. When
you do a task with a high information load, it takes up a lot of your brain capacity.
Your brain becomes selective with what it will process. So let’s try this again. Watch this video
and see if you notice a change. The younger man has approached the white-haired
man and is asking for directions. So that one was pretty obvious to us… but
50% of the people in this study didn’t notice that the person they were talking to had changed. Just like the white-haired man, they were
subjected to “change blindness”, where a visual stimuli changes, yet you don’t
notice. Like if you fail to spot the difference in these two pictures of my dog. These experiments are kind of fun, but they
can have greater implications. In another study, professional airline pilots
operated a flight simulator where the flight console information was projected directly
onto the windshield. The idea was that they could see this information and the real world
all at the same time. But… some pilots attempted to land their
plane when there was clearly another plane on the runway. They said they didn’t notice
the other plane… even though it was right before their eyes. Sometimes we don’t notice things when we’re
meant to be looking for them. Just like an experiment where a group of radiologists
were asked to look at lung scans and click on cancerous lung nodules. and click on cancerous lung nodules. 20 of
the 24 radiologists didn’t notice something unexpected… a little gorilla. Eye tracking showed that 12 of the 20 radiologists
looked directly at the gorilla. They just didn’t notice. The gorilla strikes back. People miss the gorilla – wherever it pops
up – because our brains trick us into thinking we see and know much more than we actually
do. For example, when you were watching this video,
did you notice how many times my shirt changed? See you next Thursday.


Put your observation skills to the test.
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BrainCraft is written and hosted by Vanessa Hill ( for PBS Digital Studios. Talking psychology, neuroscience & why we act the way we do.
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More BrainCraft!
What Cats Taught Us About Perception
How Many Choices Are Too Many?


Simons, D. J., & Chabris, C. F. (1999). Gorillas in our midst: Sustained inattentional blindness for dynamic events. Perception-London, 28(9), 1059-1074.

Door study:
Simons, D. J., & Levin, D. T. (1998). Failure to detect changes to people during a real-world interaction. Psychonomic Bulletin & Review, 5(4), 644-649.

Plane study:
Haines, R. F. (1991). A breakdown in simultaneous information processing. In Presbyopia research (pp. 171-175). Springer US.

Radiologists and the invisible gorilla:
Drew, T., Võ, M. L. H., & Wolfe, J. M. (2013). The invisible gorilla strikes again sustained inattentional blindness in expert observers. Psychological Science,24(9), 1848-1853.

Most, S. B., Scholl, B. J., Clifford, E. R., & Simons, D. J. (2005). What you see is what you set: sustained inattentional blindness and the capture of awareness.Psychological review, 112(1), 217.


Author: dhobson