January 05, 2003
Cognitive Biases

Clifford Pickover's ESP Experiment. The Nine-Year-Old saw the trick on her second run through the "experiment"--doing much, much better than me.

Posted by DeLong at January 05, 2003 05:14 PM | Trackback

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I think I got it after about fifty tries. Dr. Clifford is one smart guy, and so is your daughter. But I won't give anyone any hints.

Posted by: alf on January 5, 2003 06:39 PM

Took me about 10 tries through, but most of those ten involve me going into two- or three- minute deep thinks beforehand as I built and then rejected test structures.

And then realised that my test structures hadn't accounted for one possibility...

Posted by: Andrew Edwards on January 5, 2003 08:33 PM


Posted by: Brad DeLong on January 5, 2003 08:44 PM

This is cute bit of trickery. I like a lot of the (incorrect) explanations sent in, especially the ones which claim the website tracks the users eyeballs. (Those magic computers, how ever do they work! :)

For those who have trouble figuring it out, a pen and paper might come in handy.

As an aside, good thing uncorroborated eye-witness testimony has been somewhat depreciated over the past 20 years or so.


Posted by: vsa on January 5, 2003 09:58 PM

I would say I got it after around 4 or 5 tries.
The explanations were both funny and a bit depressing.

Posted by: roublen vesseau on January 6, 2003 12:35 AM

I would say I got it after around 4 or 5 tries.
The explanations were both funny and a bit depressing.

Posted by: roublen vesseau on January 6, 2003 12:35 AM

You guys are really pissing me offfffff...

*shaking fist at the skies*

Posted by: Michael Harris on January 6, 2003 01:07 AM

OK. Got it now. *shamefaced*

Posted by: Michael Harris on January 6, 2003 01:39 AM

i'm wimping out here...does anybody feel like posting a solution w/spoiler space?

Posted by: mark on January 6, 2003 01:50 AM

A hint for the perplexed:

Try choosing two cards at a time.

Posted by: on January 6, 2003 02:08 AM

A further hint:

After you've tried two cards, try three.

Then try four.


Posted by: Jim Harris on January 6, 2003 06:01 AM

I got it on the first try, but then I've practiced a bit at card counting. I'm curious if this is a strong effect: anyone else here who's done some card counting? How did you fare?

Posted by: Ben Vollmayr-Lee on January 6, 2003 06:13 AM

I suspect that this is much harder to pull off if you used cards with less clutter: say, a - 6.

This is also why as a volunteer EMT / Fireman, I am deeply distrustful of eyewitness accounts at accidents.


Posted by: Suresh Krishnamoorthy on January 6, 2003 06:38 AM


if you still want a hint, here is one:

the 98% accuracy claim is a myth. It is definitely not 98%


Posted by: Suresh krishnamoorthy on January 6, 2003 06:43 AM

I'm usually terrible at this sort of thing, but I figured it out on the first try. I think the reason is that, because of Brad's daughter, I knew it was possible to figure it out on the first try. If I hadn't known that, I probably would have floundered as much as anyone else.

Posted by: Patrick Nielsen Hayden on January 6, 2003 08:14 AM

" got it on the first try, but then I've practiced a bit at card counting. I'm curious if this is a strong effect: anyone else here who's done some card counting? How did you fare?"

I was ablackjack dealer for a while, so I dabbled in that a bit, and I, too, got it on the first try. Though, like, Patrick said, that may have more to do with the fact that I knew it was possible to see the trick on the first try, so I was more observant than usual.

Posted by: kevin on January 6, 2003 09:13 AM

Lost count, ten tries or so: sneaky!

To quote a horrible band I loved during my cloudy-headed youth:

"Ever think you're smart and find out that you aren't?"

Posted by: David A on January 6, 2003 09:31 AM

Took me about 10 times.

Then I felt really, really embarassed.

Posted by: Curtiss Leung on January 6, 2003 10:16 AM

Got it on the first try . . . my wife wasn't so lucky

Posted by: Bobby on January 6, 2003 11:13 AM

Look at the cards very very closely! Count how many cards/suits are in a deck.

Posted by: Karen on January 6, 2003 11:30 AM

I found this test through CalPundit actually--I only came over here because Patrick recommended your con report.

For the record I got it second time through and so did my resident rocket scientist, but his second time through took longer than mine.

MKK--oh, and the con report was tres funny

Posted by: Mary Kay on January 6, 2003 11:58 AM

I should have mentioned in my earlier post my theory about card counters having an advantage. When I was practising memorization, I felt something like a shift from a "visual" pattern memory (pretty red kings) to something different (roughly, a table). My first time through the esp game I followed instructions, but without really trying I remembered the cards on either side my selected card, so I lucked into the secret by trying 3 cards the first time through. It seems that others have had the same experience.

Posted by: Ben Vollmayr-Lee on January 6, 2003 12:57 PM

Clever clever nine year old. Not so clever me, took 8 times. Oh well.


Posted by: on January 6, 2003 01:22 PM

Got it on the 2nd try. If you assume the computer has no special ESP powers, and that it will be correct all the time *no matter what card you pick* -- even when you click the same eye on each try -- then the logical conclusion becomes clear.

I don't know, that might not make sense at all, but it does in my head.

Posted by: YM on January 6, 2003 01:25 PM

I got it my first time, on YM's reasoning. FWIW, I'm a bridge player (although by no means an expert one). However, I don't think that had anything to do with it; I just hit a lucky line of thought.

Posted by: Joathan Goldberg on January 6, 2003 02:52 PM

What I find so interesting about the responses is that so few people have a fundamental grasp of how magic works-- i.e., 1) There is no ESP so it's a trick, 2) Tricks generally work by misdirection so I must not be seeing what I think I'm seeing, 3) Compare what I saw the first time to the second time... at which point, especially with pen and paper in hand, the solution should become obvious. But the vast majority of people seem to start in a different logical direction-- i.e., "Mind control must be real and operating through my computer even via a 56K modem," or "People's behavior is so completely predictable that a subliminal effect like flashing or varied brightness could force 98% of us to pick the same card"... I have a feeling this explains a LOT about the world and how people see it.

Posted by: Mike G on January 6, 2003 03:01 PM

I too am a bridge player - but it took me 3 turns - perhaps explains my card-play.

Posted by: Peter S on January 6, 2003 08:26 PM

Never take the other fellow's bar bet. It also took me 6 or 7 tries before I realized that the spade 3 was not the club 3, and vice-versa.

Posted by: Tom S on January 7, 2003 09:49 AM

It occurs to me that a friend from Ghana once told me that, in his country, trickery is used to hunt monkeys. First the hunters play catch with fake, harmless spears, as the monkeys watch. Then they switch to real spears and throw them to the monkeys, who try to catch them and are impaled (big laffs). The monkeys are just intelligent to be tricked (unfortunately, I can't recall the trick described to me by a Philippino acquaintance, except that it ends with the monkey's head exploding somehow).

The point is that we are the monkeys here, which is why this was tougher for us than for the 12 year old.

Posted by: David A on January 7, 2003 09:57 AM

I just had a really evil idea: duplicate the test but rather than embellish it with paranormal claims, state that it proves hard AI because it shows that ESP can be computationally simulated.

"Not only does the room understand Chinese, but it can READ YOUR MIND!"

Posted by: Curtiss Leung on January 7, 2003 10:12 AM

OUCH!!! That'll teach me not to LOOK PROPERLY!

Posted by: Emma on January 7, 2003 11:08 AM

This gentleman gets to sell me my next used car.

Posted by: Brendan on January 7, 2003 04:17 PM

On a related (?) area, did you know that you can emulate Newcomb's Paradox using the Telephone Indian/Inverse Pyramid swindle to select from a pool of volunteers to "show" the survivors that you can really do it? It might be worth it, just to see what happens to them/to screw with their minds. Maybe it would be a fitting way to treat students...

Posted by: P.M.Lawrence on January 7, 2003 04:43 PM

I figured it out on the second try, my mom got it right away, but my dad (the smart one in the family) took a full 15 minutes and still needed a couple of very obvious hints from me.

The whole thing is clearly designed to generate those screamingly funny comments speculating on how it works and what uses the government make of such mind-reading software. A prank of genius.

Posted by: Gabardine on January 9, 2003 01:28 AM
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