The Stroop Effect occurs in a mismatch of word with color.  You are told to say the color of a word but its letters spell a different color. Repeatedly subjects react slower to a mismatch than they do to a match of color with word. For your own experience of the Stroop Effect take the "test" below.

Now notice how much more easily and quickly you can match and pronounce the colors below.


These colors do not require scrutiny.  The words and colors fit what your brain expects. This provides an example of the default mode for how we process the world.  Our brains do not like anything not fitting our preconceptions. Natural selection evolved brains to survive, not reason with the world. They fitted things into ready categories so our ancestors could avoid a tiger they saw lurking behind a boulder, even though the tiger was there only once and they had detoured around the rock scores of times since. The simple equation was rock=danger and brain neurons became wired for that. It made life easier.  So brains do the same today.

This effect is noteworthy in a post-modern era when fake news and alternative facts have become widely acceptable.  It helps explain why people believe what they want to believe.
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