Cognitive Daily

Cognitive Daily reader “Jokermage” pointed us to a web site which claimed that it could predict with 98 percent accuracy what site visitors would be thinking after a short quiz.

I tried the quiz, and indeed, the site appeared to “predict” my thoughts. But could it really do this with 98 percent accuracy? We’ve decided to see if we can replicate the process here. I’ve created two different quizzes, one which exactly replicates the original quiz, and another which is slightly different. So that we can divide participants into two roughly even groups, click on the appropriate link below:

Click here if your birthdate is an even number

Click here if your birthdate is an odd number

You’ll have until 11:59 p.m. Eastern time on Wednesday, April 26 to participate, or until there are 400 responses. The study should take no more than a minute or two to complete. Make sure you click through to the survey site to record your response!

Since there is some “secret” information involved, I’m going to close comments on this one.

Update: Jokermage has a blog.

Update2: We’ve received enough responses, so the survey is now closed and I’m opening up the comments. You can still try both tests by clicking on the links above, but after you’re done, you’ll simply return back to Cognitive Daily.


  1. #1 Judith
    April 24, 2006

    If the response was half-right, am I still in the top (or bottom?) 2%?

  2. #2 Dave Munger
    April 24, 2006


    We’ll break down responses both ways when we analyze the data on Friday. But the claim from the original Web site was that 98 percent of respondents said they were thinking of a “red hammer,” so in order for the claim to be true, we’d have to rule out responses like yours.

  3. #3 boojieboy
    April 24, 2006

    Not sure which explanation holds, but I’d guess it’s one of the following:

    HYP1: They may be using subliminal primes, placing a red color patch and the shape of a hammer behind the numbers that you use to calculate with. Each time the numbers switch to a new set, they briefly flash the color and shape, then the new set of numbers come up, masking the color and shape. I tried again but couldn’t see anything, still doesn’t mean it couldn’t work.

    HYP2: Relies simply on strongest associates. The math calcs are a sham, designed to throw you off. If you were to dispense with the calcs, and just ask people to name a color and a tool as fast as possible, 98% of the time they’d say red and hammer. Quick, name a color and a tool (red hammer 98%)

  4. #4 Dave Munger
    April 24, 2006

    I can assure you, we used no subliminal primes, so HYP1 is out. You can examine the source code of the HTML to convince yourself.

    I think there’s something to the calculations as well, but I’m going to hold off on giving my explanation until Friday.

  5. #5 ThePolynomial
    April 24, 2006

    I would love to see synesthetics take this quiz to see if they have stronger associations with the numbers. My thought was that they got you accustomed to prime (or maybe they were just odd? I don’t remember) numbers, and then smacked you with a nice round even number at the end. I tend to associate odd numbers with more citrus-y colors and even numbers with red/blue/purple. At least I generally do. I don’t know how common that is.

    I, however, thought of neither the “right” color nor tool (my tool wasn’t even in the set of possible answers).

  6. #6 Chris
    April 24, 2006

    It didn’t end up working for me. I thought “orange wrench”. *shrug*

  7. #7 Greco
    April 24, 2006

    I did think of a red hammer.

  8. #8 Jenna
    April 25, 2006

    It came up “Yellow Screwdriver”. I thought “Orange Hammer”. Well, I always was an independent thinker anyway….

  9. #9 Dave Munger
    April 25, 2006

    Just to eliminate some confusion, I should let you know that the original site (here) claimed that you’d think of a red hammer. We designed two versions of the same task, one which duplicated the red hammer test (even birthdays), and one where we tried to get you to think of a yellow screwdriver (odd birthdays).

  10. #10 MacSmiley
    April 25, 2006

    Odd birthday, yellow screwdriver… but I thought of red hammer.

    But then, I am a little odd.

    Mac user and all.

  11. #11 ThePolynomial
    April 25, 2006

    Chris, my soulmate! I thought of an orange wrench, too!

  12. #12 Paul Plotsky
    April 26, 2006

    Odd birthday and slightly odd answer – red screwdriver. How does this score?

  13. #13 Sharon
    April 26, 2006

    I’ve always assumed this is because the numbers build up to and repeat a value over ‘hundred’ – it’s priming. Repeating the word ‘hundred’ locks in the ‘huh’ and ‘red’, so when quickly asked to come up with a coloured tool, red is already primed, and so are words beginning with ‘h’. Hence most people will come up with a red hammer. A similar example uses the number six, first getting you to calculate 1+5, 2*3 etc. until you’re saying the word ‘six’ repeatedly, priming the ‘ck’. You are then asked to quickly think of a vegetable and most people will say carrot (cauliflower, cabbage and broccoli being the most common alternatives).

    Derren Brown uses priming as one of his techniques in his programme ‘Mind Control’ running in the UK. You can see some examples at

  14. #14 lefty
    April 26, 2006

    Well I can provide a counter example to the numbers priming me because I didi teh sums in Greek and thought of a red hammer & a yellow saw!

  15. #15 Marc
    April 26, 2006

    What, if anything, influenced psople at all? My reply was “Blue Chainsaw”.

  16. #16 Rob
    April 27, 2006

    FWIW, I just did the “odd-date” test with my girlfriend looking over my shoulder, and *both* of us selected Red Hammer. Which was weird on a couple of *additional* levels… 😎

  17. #17 Enzo
    June 6, 2006

    I did all the calculations in my mind in italian also and came up with red hammer. I became bilingual in english as an adult age, so it’s not repetion of a sound or association of it.

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