How easy is it to name the color of a word? As it turns out, not that easy—at least when it clashes with what the word says. This difficulty is known as the Stroop Effect, named for J. Ridley Stroop, whose 1935 study was the first to demonstrate this phenomenon. When you see the word "black" written in black ink, naming the color of the ink is easy. Same with seeing the word "pillow" in black ink. But when "black" is written in green, it may take you at least a moment to figure out the right answer. This is a demonstration of how our brain is so comfortable with some tasks that they happen automatically; in this case, we read and interpret words without paying attention to the physical characteristics of the letters themselves. This effect is so reliable that it's used in many psychology studies to test attention. Try it yourself in the videos below.
Take The Stroop Test
Professor Bruce Hood leads an audience through this surprisingly difficult task.
A Demonstration Of Selective Attention
Examine how your brain works with another classic attention test.
Key Facts In This Video
Test your attention with this short exercise: 00:12
Inattentional blindness occurs when you don't notice an unexpected stimulus that is right in front of your eyes. 01:29
In one study, most radiologists who were told to find cancer nodules in lung x-rays failed to notice a small gorilla on the display. 03:12
Selective Attention Card Trick
Count how many red cards are in the deck.
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