[WikiEN-l] Captcha word quiz

[Neil Harris]

Theresa Knott wrote:
> On 3/20/06, Steve Bennett <stevage at gmail.com> wrote:
>   
>> On 3/20/06, Theresa Knott <theresaknott at gmail.com> wrote:
>>     
>>> Sorry i thought a catchpa was a wiggly word  _image_.  What I am
>>> descirbing could easily be text.
>>>       
>> Invent one then ;) Bear in mind that if it's multiple choice, then the
>> robot could just have a few goes.
>>     
>
> A colour that's the opposite of black
>
> the number of days in a week
>
> A pet animal that goes woof woof.
>
>   
Unfortunately, Googling and word-counting is a rather powerful way of 
cheating at these sorts of simple general-knowledge questions:

Searching for "animal that goes woof woof". removing trivial words from 
the page fragments Google returns on its search page, and then counting 
the most common remaining words gives the following:

43: woof
9: animal
8: dog
7: goes
6: joke

for "colour that's the opposite of black" we get:

21: colour
10: black
6: opposite
6: white
5: you


If you then try the words which are not in the question, the highest 
rated few words tend to contain the answer to the question. Even if we 
try at random from the top-rated words, there's a good chance of 
success, which is all a bot needs.

-- Neil