On 28 February 2014 18:29, Brad Jorsch (Anomie) <bjorsch(a)wikimedia.org>wrote;wrote:
On Fri, Feb 28, 2014 at 12:07 PM, Mansi Gokhale
<gokhalemansi12(a)gmail.com
wrote:
Then there's the issue of different interpretation. Take for example
https://www.mediawiki.org/wiki/File:Find-all-captcha-idea.png. Is the
second image wearing glasses? Or is that a lorgnette or something like
opera glasses, both of which are held in front of the eyes rather than
worn?
https://www.mediawiki.org/wiki/File:Find-the-different-captcha-idea.pnghas
a similar problem. The first image is the only one with a cigarette, and
the only one with non-realistic coloring. The second is the only bald one,
and the only one with something resembling a lorgnette, and the only one
not looking in the general direction of the camera, and the only one with a
book. The fourth is the only child. The sixth is the only obvious female
(I'm not sure about the cat). The eighth is the only one smiling, and the
only one with visible teeth.
I think this is oversimplifying. Of course some people can interpret a
picture puzzle in slightly different ways - the whole *point* of a captcha
is to distinguish between the intuitive reasoning of a human and the
formulaic reasoning of a computer; if there was absolutely no ambiguity, it
would be a very poor captcha. In exactly the same way that the letters on
a captcha will sometimes be distorted in such a way that humans genuinely
make a mistake, sometimes the questions in a picture puzzle can be
sufficiently distorted to the point that they are answered incorrectly.
The 'difficulty' of *any* captcha obviously needs to be carefully
calibrated to hit the sweet spot between mundanity and ambiguity. But
putting out nine pictures of humans and one picture of a cat and asking for
the "odd one out" is no easier to misinterpret than a squiggle that might
be a G or might be a 6.
--HM
