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December 23, 2005


At night, when we're sitting around the condo listening to bruises form on our bodies, we've been playing with a little electronic 20-questions gadget that looks sort of like this. It's amazing: You think of something -- say, a bottle cap, or the pyramids -- and it asks you 20 yes-or-no questions that often seem odd, such as "Is it heavier than a duck?" and "Does it give joy to people?"  The questions are so strange and seemingly unfocused that we're almost always convinced it's not going to guess the answer, but most times, somehow, it does. It wins so often that for a while there we thought maybe it had a hidden microphone and was listening to us talk, so we started using code words for the object we'd picked, and it still usually got it right.

So I have two questions:

1. Does anybody know how it works?

2. Could we modify one of these things and have it replace the federal government?


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1. It uses artificial intelligence. Actually, that's one of the oldest examples of AI.

2. The fact that it has intelligence, artificial or otherwise, automatically disqualifies it from government work. Although... it *might* make a good replacement for judi. *wink*

*goes and gets his modified Clapper Ogasmatron to see how to merge the 20 Question thingie*

Let's see, add a little here, take a little off here.


Lab: Could you explain what you mean by "It uses artificial intelligence"?

1. magic 2. yes please

If it's not a benevolent dictator, I have no idea... but more importantly, Dave Barry - I just love that you write and make me laugh. Merry Merry to you!

Dave, will you PLEASE ask it where I put my damn car keys.. I'm late for work.

Well, it has (usually) a binary tree database that it balances. It tries to keep the depth of the tree at most 20. So, each question makes it go down the left branch if you say yes, and right branch if you say no. When it reaches a leaf node (no more branches) then it has found the object it thinks you picked.

Most versions, if the guess it has is wrong, will then ask you to enter a new question that it can ask so that it can tell what you picked from what it thinks you picked. So, if it said you picked a howitzer, but you really picked a turnip, it would ask you to enter a question that distinguishes a howitzer from a turnip.

I just read my own answer and I can shorten it: blah blah blah boring blah blah. And that's how it works.

Still, if you can get one to cuss you out on occasion, it would make a fine stand-in for judi when she's on vacation.

One word HUH?

*thinks he go with "Smoke and Mirrors" as the answer*

Try letting the smoke out and see if it continues to work....

LabSpec, I hope it's good at that, because I've never been able to distinguish a howitzer from a turnip.

By the way, would you like to come over for a salad this evening?

An example! If I had just TWO items, and you had to pick one of the two, then I'd only need one question to determine what you were thinking.

Item 1: The pyramids. Item 2: a duck.

Question: Is it heavier than a duck?
If yes, then it's the pyramids. Otherwise it's a duck.

Okay, now I add a bottle cap, and a new question. "Does it have feathers?"

Question 1: Is it heavier than a duck?
Yes: pyramids
Question 2: Does it have feathers?
Yes: It's a duck
No: It's a bottlecap.

Notice that after question 1, with a yes answer, I could have had another question: "Does it have wheels?" and added an object with wheels. A binary tree with depth 2 can have 4 leaves. That is, four items. So, a binary tree with depth 20 can have 2 to the power 20 leaves. Over 1 million items. Add in some "maybes" and "does not apply" type answers and yowza! That's lots of things people can pick! You can also do other neat tricks to increase the number of items.

Think of a sock monkey and see if it guesses it.

Dave (nB): I'm not so good at telling them apart either. You should have seen my garden last year.

And when we answer Dave's question, it's time to figure out how http://trunks.secondfoundation.org/files/psychic.swf

Sorry I don't know how to insert a link the cool way.

Lab, I need to know how Cheesewiz's link works RIGHT NOW!

Sounds kinky, but I don't mean it that way. (Yes, I do.) (No, I don't.) (Yes, I do.)

Hey! I bought this as my secret santa gift this year ... it was a hit ... sort of. Although ... it DID NOT accurately guess "garter belt". I don't know if that speaks more to the players or the game.

The psychic one is just simple math. You'll always end up on 0, 9, 18, 27, 36, 45, 54, 63, 72, or 81. So it puts the same symbol in each of those spots (choosing a different one each time so you don't catch on), fills in the rest randomly, and ta-da.

It's the result of a long line of coding on the internet in the same way that was described above, I believe at www.20Q.com When they got enough entries there they just put it in this form. My family and I were bewildered by it.

We did one that we didn't think it would get. It was asking us all the normal animal questions like "Is it colorful", "Does it bring joy to people"

Question 20: "Is it used in the dark"

I am forced to press yes. 20Q knew I was thinking about Batman.

Cheesewhiz: No matter what you do, you'll get a number that's divisble by nine. Notice how all the images are the same for 9, 18 etc up to 81 (90 and 99 and 0 are impossible). And that's your answer. The embarassing part, once I thought I had 'trumped' the system. When I figured it out, I realized that I just couldn't do arithmetic. *SIGH*

And@Lab, I understand the explanation perfectly (from the first one on down). The fun part of that game is thinking up esoteric items unlikely to appear on that list. There's a web version of that game somewhere, but I don't remember where.

dave's cell phone called me at work and left a message during a particularly intense session with this machine, the other night.... but don't worry, sir, i don't listen and tell.

lab darlin': it starts with f. can you guess the rest?

Lab: Excellent! Thanks.
Punky: Believe it or not, one of the words we managed to stump it with last night was "garter." Although we got into a big honking argument over how to answer the question "Is it flat?"
Going skiing now. Bye.

Judi -

Q1: Does it rhyme with "Fondue"?

Bye Dave!

Thank you all for explaining the Psychic game and striking another blow against magic and wonder.

There really isn't a Santa Claus is there?

There's always this....

20Q.com took 23 questions to come up with "booger". To be fair, though, we disagreed on the answers to "Can it be found in church?" and "Can it be placed on your head?" (I said yes to both.)

Can someone tell me how this works?

Lab - pretty much only us geeks understand binary trees, but good explanation!

Punky - Good to see your shining post again.

And MKJ reappeared yesterday after a long absence.

Steven - let me be the first...

None of the cards in the set you pick from are in the 2nd set they show you


Boy, do I feel stupid now!!

The card thing is not quite as elaborate as binary trees or hexadecimal plants or whatever. If you notice, not a single one of the cards it originally shows you is up there. They fool you by keeping all the royal cards up there, just in different suits from what they originally showed you

steven, write down the cards you pick from, compare to the ones shown after.

Steven - the trick there is that NONE of the cards from the first set are in the second set...

OOps - that's what I get for not refreshing before responding to someone's question... :)

Good to see ya Punky! Merry Christmas sweatums!

20Q came close when the word was "penis". It guessed "urethra". Best Question: "Can you use it with your friends?"

I have one of these. The one thing it can't seem to guess is t-shirt. It always seems to think I'm talking about socks or underwear. The gadget gives me an amount of anxiety--I'm afraid I'm answering its questions wrong, rather than it just guessing incorrectly.


Um. thanks Bob. I was stumped. I forgot that the data selection set was variable and didn't notice they changed it each time after showing a blank screen.

Hi Punky. And hi Kibby!

I'm still stumped on the psychic thingee, but, bear in mind, my mind is not working today. (Where am I?)

How does it "know" which multiple of nine I am choosing at any given time?

T which rhymes with C. - look at all the symbols for the multiples of 9, notice anything?

T/RWC - It doesn't matter which one. They're (not [not their] there) all the same.

Not either! Different symbols! I thought at first they would all be multiples of some number and all the possible numbers would have the same symbol, so that you could just click the globe and the same symbol would show up over and over again, but it does not.

I'll look again tomorrow. I have The Salmonella today, and it's better than rum, I tells ya!!!

I stumped 20Q with telephone...

The symbols change after you click the crystal ball, but all of the multiples of 9, up to 81, will be the same symbol. For the math challenged: 9, 18, 27, 36, 45, 54, 63, 72, 81.

Why is it that way? You start with a two digit number. The two digit number can be written 10a + b, where a is 1 through 9, and b is 0 through 9. You then subtract a+b.
10a + b - (a + b) = 10a - a + b - b = 9a
So, you always end up with a multiple of 9, less than or equal to 81, greater than or equal to 9.

So, when you click on the ball, it will show you the symbol for 9, which is the same symbol as all the multiples. Don't look at 90 or 99 since you cannot end up with numbers that big.

Ohhh, it chaaaanges.

Stupid my brain.

Lab: Does this mean that someone had to go through a list of 100,000 objects or so and program it with reasonable answers to each question it might ask?

Try "walrus penis bone." I bet the boys in the Lab never thought of that.

or 'fossilized dinosaur poop' (we could never decide if it was animal, vegetable, or mineral)...

Insom - a "coprolite" or "coprolith" is a mineral. It once was vegetable matter (or meat, depending on whether the dinosaur was a carnivore or herbivore), and passed through an animal, but once it's fossilized, it's mineral.

Merry Christmas from the Department of The Guys Who Know Too Much For Their Own Good.

Dear Mr. Completely,

So like, when you erase the blackboard? Like where do the words go?


*snork* @ pogo!

I feel really dumb after reading this thread.

southerngirl - me too feel dumb. I don't understand one word of any explanation *sigh*

My understanding is that, in addition to what Lab is saying, you can actually tell it a "wrong" answer (one that's inconsistent with what it was expecting for the object) and still it should guess the object right after enough more questions. The machine learns each time you play it, remembering your answers and adding them to the mix. Each answer you give is like a vote for the object's characteristics. So if everyone who played insisted that the pyramids were not heavier than a duck it would learn to use "not heavier than a duck" as a clue that someone was thinking of the pyramids (it isn't able to tell what answers are actually right, just figure out what everyone says is right, much like politicians). Also if you keep doing the same object over and over again you should be able to notice it getting better and better at guessing that object based on your answers.

The method it uses is probably something like asking, "Which objects, according to everyone else's answers, have the most of the characterstics he's said so far, and which question will best narrow down the field?" When you buy the handheld one it's got hard-wired "training" (as though someone sat down and played for a long time already). The online version should be better at it since it learns from everyone who plays.

If you go to 20q.net you can try an online version of it.


1.St. Judi has vacations?

2. I need some math help here.
Today, when I got home (stayed in Bismarck last nite, rather than drive home @ midnite) I found, in my mail, my most recent copy of Funny Times. Its monthly Dave Barry item was written about his skiing venture with the family in Vermont (The Wind Chill State, in Dave's words) ... I thot this really neato, this juxtaposition of skiing trips with family, on the blog, and in my favorite newspaper ...

The math thingy is this: In the Vermont column, Dave says that his son (he does not name the Weinermobile riding lad, but we all know the young gentleman's name ...) is eight years old.

So, how many years ago did Dave ski in Vermont?

And, more importantly, why did he seemingly fail to learn anything from this lesson in life, and thereby find his ownself on another ski trip?

I bought one of those for my brother's ninth birthday. My family had driven from CA to UT and they all played with it on the drive home. He had a hard time holding on to it, it was so popular.

St. Judi: You can call me at home or on my cell all week. Sorry I missed you. Hugs and kisses.

Same to you, Dave. Although I'm a lot less likely to believe you are Real. *wink*

Try symphisis pubis and see if it guesses the right answer ... the reason I'm using that nomenclature is 'cuz of something I saw @ my security check in SoCal ... I'll tell that story on a thread above ... when I get back there ...

20Q.com is awesome. It got tricycle in 10 questions. What made it guess tricycle as opposed to bicycle?

For Christmas tree, it's first question was if it is found in a church. Is it learning based on the time of year and this being a common item thought of?

This does the same thing with Darth Vader. He runs for president a lot, so sure, it could replace the government.

We had one of those 20Q things in my house. We worked to stump it with abstract concepts. Hard to answer the questions though...

So, my sister gave me one of these (http://www.latestbuy.com.au/shock_lie_detector.html) to keep everybody honest! It's a 'lie detector' that shocks you when you lie. Actually, it mostly just shocks you. No one has been brave enough to try the "HIGH" setting. Hours of fun, if I had any friends left to use it on!

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