Friday, June 1, 2012

The Stroop Effect

What is the color of each words below? Say the name of each color aloud as you look at each word:

Green  Red  Blue  Purple  Blue  Purple

Now do the same thing for the words below. Don't read the words. Just say the name of the color of type used for each word.

Blue  Purple  Red  Green  Purple  Green

For most people, the second task is more difficult. It takes longer to name the colors when the word doesn't match the color, and mistakes happen more often.

This experiment was first conducted by John Ridley Stroop in 1935, and has been used to understand how different pathways of information can interfere with each other in the brain. 

One explanation for why we have such a hard time sorting out the conflicting information is that it takes us longer to identify the color names than it does to read the words, so the brain has to go back and reconfigure each guess.


Lester Yocum said...

Great post, Jim. It definitely "got" me.

Totally off the subject -- I pulled up your son's "Hay Brigade" album of contemporary Irish music as I was painting today. Totally immersive; really tough to paint as I was bouncing to the tunes, humming along. Couldn't keep my brush straight. Good stuff.

James Gurney said...

Thanks, Lester. I miss having him playing in the studio as I paint. You've given me perfect chance to plug my son Dan Gurney, who is now living in New York, playing accordion ( and developing a concert streaming site (

Keith Parker said...

Aha! I was wondering the relation. Accordion eh? That's something you don't see much anymore. Beautiful instrument though. I only know two people that play one. One of them is in her nineties.

jeffkunze said...

Actually I didn't have much trouble with the second line and might have done it faster, but I might have cheated a little. I think I was using my peripheral vision to identify the colors before I focused on the letter patterns. Might be a little trick.

I tried doing it backwards and didn't do nearly as well.

António Araújo said...

Jim, I read somewhere that the effect was used at some point to detect spies.

For instance, suppose you had someone who you suspected to be russian but who claimed otherwise. Then you would run this test through him, with the words written in russian. If he was slower on the second sequence or made more mistakes then you'd have evidence that he understood written russian.

Jeffkunze: I also cheated, by unfocusing a bit and losing context (also, looking at the last letter of the word and the space after that). It works, though I think I was still a little bit slower on the second row. It makes me think that once the enemy spies hear of the test they can train to beat it :)

robertsloan2art said...

Wow. I've been paying more attention to my art in the past few years. The first time I ran into this test, I noticed how long it took to identify the colors in the second row and did make some mistakes.

This time was almost as fast with no mistakes. I think I've been staring at my palette for too long! Thanks for posting it, this sort of thing is fun!

Gregory Lee said...

I have a theory. For the first task, we just have to read off the written series of words, and that is something which we've had lots and lots of practice at. For the second task, we have to say the colors of a series of things, but that is something most of us have had little practice at. (You and other artists might be exceptions.)

Here is something similar. I once thought I might train myself to better recognize aromas, and I took a bunch of identically shaped spice bottles, closed my eyes, shuffled them, chose one at random, opened it and sniffed, then tried to say aloud the name of the spice. I found that I just couldn't do it. I would know the aroma perfectly well, but I couldn't say the name.

Maybe putting names, actual pronunciations, to things is something that requires task-specific practice.

Laura G. Young said...

I didn't have any trouble with this exercise whatsoever; but being somewhat colorblind I suppose I have a rare advantage. ;) Wonder if they COULD design a setup that would trick the mind of, say, an anomalous trichromat, but using a different set of parameters?

Greg Stevens said...

The Stroop task is very interesting. There is a theory, the Dimensional Overlap Model, that talks about exactly how and why the Stroop effect happens.

Oh... one more piece of trivia: It was actually discovered before Stroop, by a German psychologist named Jaensch! But he only published the idea in German, so word didn't spread. :-)