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Re: Captcha and inaccessiblity

From: Charles McCathieNevile <charles@w3.org>
Date: Mon, 20 Oct 2003 00:16:19 -0400 (EDT)
To: Marja-Riitta Koivunen <marja@w3.org>
Cc: Tom Croucher <tcroucher@netalleynetworks.com>, "w3c-wai-gl@w3.org" <w3c-wai-gl@w3.org>
Message-ID: <Pine.LNX.4.55.0310192308060.10736@homer.w3.org>

Right. The idea of having multiple options would mean that we think we get a
wide coverage of people, without letting in computers.

This kind of questioning is notoriously difficult.

lots of IQ testing and the like has been demonstrated to be inaccessible to
people because they don't grow up in the same environment as the writer of
the test.

Australians in the US get a remarkable amount of fun, after comments on how
well they speak english, telling outrageous lies about how they learned it
because some people don't realise that Australia is an english-speaking
country. And a frenchman arriving in Australia was (reportedly) appalled to
be accused of entering on false papers, in part because he couldn't sing the
Marseilleise - the french national anthem. (It is generally reckoned that
about half of all Australians know one complete verse of our national anthem
- and about a quarter of us mistakenly believe it is "Waltzing Matilda").

But there are questions that people can answer - at least being able to get
mostly right answers for a handful of simple tests where a computer is
expected to fail them all.

More detail below, but the same idea...

On Sun, 19 Oct 2003, Marja-Riitta Koivunen wrote:

>>>I spoke to the guys at CMU about some stuff I was interested in with text
>>>based captchas a while back (6mo maybe) and they said they were working
>>>on a text version. This would probably take the form of a question which
>>>is common knowledge or analogic. ie, "If I have five apples and I eat
>>>three. I give one to Bob but Susan gives me two apples, how many apples
>>>do I have?". To which the acceptable answers would be "3", "three", "3
>>>apples", "three apples". Another example might be like those IQ tests "A
>>>dingy is to ship as a go-cart is to a?". The acceptable answers being
>>>"Car", "Bus", "Lorry" etc.

... "f1 racer", "V8", "commodore" (all types of racing cars).

>I did not know what a dingy is :-).
>We don't want to filter non-native English speakers and users with
>cognitive disabilities either.

Actually it's normally written dinghy, but anyway it's a small boat. I don't
know if the term is used in american english - one of the problems with such
a scheme is coping with the wide variety of {english, spanish, french, ...}
in use. For languages such as welsh this should be easier, but for Yolngu
languages it would be very difficult (probably only about a dozen people can
spell the words as they appear in a dictionary with any reliability. On the
other hand it is possible to build a dynamic dictionary to get around that


Received on Monday, 20 October 2003 00:18:20 UTC

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