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Thread: Alternative CAPTCHA
Number of posts in this thread: 12 (In chronological order)
From: Patrick Burke
Date: Tue, Aug 25 2009 4:40PM
Subject: Alternative CAPTCHA
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>Hmm, an interesting CAPTCHA-substitute here. It has a text question,
>with ALT-ed images as answers. The ALT isn't a direct answer but
>gives an easy clue. Works well for screen-reader.
>Would any groups be disadvantaged by this? There's always the danger
>of cultural bias in the choice of question, I suppose. Is it more
>easily hacked than regular CAPTCHA?:
<http://www.cssquirrel.com/2009/08/25/comic-update-boring-in-five-easy-steps/>;
Patrick
From: Randi
Date: Tue, Aug 25 2009 4:50PM
Subject: Re: Alternative CAPTCHA
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Could you explain where abouts on the page you found this?
From: Patrick Burke
Date: Tue, Aug 25 2009 5:00PM
Subject: Re: Alternative CAPTCHA
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At 03:46 PM 8/25/2009, Randi wrote:
>Could you explain where abouts on the page you found this?
Aha, sorry. ... It's in the section called "Leave A Reply". There are
the various edit fields. Then the instruction to "Prove your
sentience" by choosing the correct image.
Patrick
--
Patrick J. Burke
Coordinator
UCLA Disabilities &
Computing Program
Phone: 310 206-6004
E-mail: burke <at> ucla. edu
From: Randi
Date: Tue, Aug 25 2009 5:15PM
Subject: Re: Alternative CAPTCHA
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Ok, I don't get it. It says, "plese prove your sentance by clicking on
the robot" and then there are links saying like "this is a picture of
blah blah". I don't get it? Prove what sentence...
From: Webb, KerryA
Date: Tue, Aug 25 2009 5:35PM
Subject: Re: Alternative CAPTCHA
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>
From: Randi
Date: Tue, Aug 25 2009 5:40PM
Subject: Re: Alternative CAPTCHA
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Um, what? There is no sentance. Just links saying this is a picture
of. Is there a picture? Unless I am just an idiot, this thing makes no
sense. What do you mean by "sentence"?
From: Chris Hoffman
Date: Tue, Aug 25 2009 5:45PM
Subject: Re: Alternative CAPTCHA
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There's the first problem with the CAPTCHA right there: It asks you to
"prove your sentience", as in, "prove that you are a sentient being",
but the word "sentience" sound a lot like "sentence" (a string of
words or a prison term) when read aloud, so that's a problem for
screen reader users.
Two other problems are that, first, there are only three choices, so
67% of random clicks from spammers would get through. The second
problem is that the CAPTCHA problem is not generative. That is, there
is no way to create new questions automatically.
Chris
On Tue, Aug 25, 2009 at 7:13 PM, Randi< = EMAIL ADDRESS REMOVED = > wrote:
> Ok, I don't get it. It says, "plese prove your sentance by clicking on
> the robot" and then there are links saying like "this is a picture of
> blah blah". I don't get it? Prove what sentence...
>
From: Randi
Date: Tue, Aug 25 2009 5:50PM
Subject: Re: Alternative CAPTCHA
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Hahaha yeah...and when Kerry said "sentient" I thought she was being
sarcastic with me haha! They sound completely identical. Too funny!
Hey, we just really tested that thing though haha!! I love it!
From: Patrick Burke
Date: Tue, Aug 25 2009 5:55PM
Subject: Re: Alternative CAPTCHA
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At 04:41 PM 8/25/2009, Chris Hoffman wrote:
>There's the first problem with the CAPTCHA right there: It asks you to
>"prove your sentience", as in, "prove that you are a sentient being",
>but the word "sentience" sound a lot like "sentence" (a string of
>words or a prison term) when read aloud, so that's a problem for
>screen reader users.
Actually I think I would blame this one on the speech synthesizer.
Speech synth developers (& screenreading software makers to a lesser
extent) have put in quite a bit of work on getting similar words to
sound different. So, I'd say it's a bug in the speech engine if
sentience & sentence are indistinguishable.
Agree with your other points here.
Patrick
>Two other problems are that, first, there are only three choices, so
>67% of random clicks from spammers would get through. The second
>problem is that the CAPTCHA problem is not generative. That is, there
>is no way to create new questions automatically.
>
>Chris
>
>On Tue, Aug 25, 2009 at 7:13 PM, Randi< = EMAIL ADDRESS REMOVED = > wrote:
> > Ok, I don't get it. It says, "plese prove your sentance by clicking on
> > the robot" and then there are links saying like "this is a picture of
> > blah blah". I don't get it? Prove what sentence...
--
Patrick J. Burke
Coordinator
UCLA Disabilities &
Computing Program
Phone: 310 206-6004
E-mail: burke <at> ucla. edu
From: Patrick Burke
Date: Tue, Aug 25 2009 6:05PM
Subject: Re: Alternative CAPTCHA
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At 04:13 PM 8/25/2009, Randi wrote:
>Ok, I don't get it. It says, "plese prove your sentance by clicking on
>the robot" and then there are links saying like "this is a picture of
>blah blah". I don't get it? Prove what sentence...
It says "sentience " not sentence. As in "sentient being". Think Star
Trek ... <grin>
So if the instruction says to click on the robot, you choose the
"metal man" graphic. If it says "Squirrel", choose "animal that eats
nuts & lives in trees". etc.
So, ok, maybe this example isn't so great. At least it could use some
clearer instructions. ...
Patrick
--
Patrick J. Burke
Coordinator
UCLA Disabilities &
Computing Program
Phone: 310 206-6004
E-mail: burke <at> ucla. edu
From: Randi
Date: Tue, Aug 25 2009 6:10PM
Subject: Re: Alternative CAPTCHA
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Oh!! Oh!! Oh!! Got it, thank you Chris, thank you thank you. It sounds
just like sentence. If I had interacted with text and spelled it, I'd
have gotten it. So the whole point is just to click one of the links?
It doesn't matter which? The wording most definitely needs to be
different. Even your and you're are impossible to differentiate
without spelling out.
From: Simius Puer
Date: Wed, Aug 26 2009 4:10AM
Subject: Re: Alternative CAPTCHA
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>
> >Hmm, an interesting CAPTCHA-substitute here. It has a text question,
> >with ALT-ed images as answers. The ALT isn't a direct answer but
> >gives an easy clue. Works well for screen-reader.
>
> >Would any groups be disadvantaged by this?
>
CAPTCHAs have long standing accessibility and usability issues and this is
yet another great example of an attempted work-around with its own issues.
"Would any groups be disadvantaged by this?" the answer is yes. In terms of
*accessibility *this could hamper users with cognitive disabilities. I've
not tested the page using any assistive technology but it appears to tab
right over images making me wonder if there are any issues for non-sighted
and/or non-mouse users. Accessibility aside there is a much wider *usability
*impact in using CAPTCHAs.
Consider older generations or people who don't use the Web very
often...these people are often unfamiliar with CAPTCHAs (often one of the
primary arguments for using them) and it can create alienation that leads
them to abandon the submission. There are also people who use the Web on a
regular basis, that suffer from no disability at all, and yet still struggle
with CAPTCHAs.
Causing confusion or creating any workload (i.e. solving a CAPTCHA) for the
user does one thing - it reduces the amount of genuine submissions. Not
something any organisation, profit making or otherwise, would aim for.
The thing is that there *are* alternatives to CAPTCHAs , ones that are both
usable accessible (if implemented correctly of course) and more importantly
- do *not* put any additional workload on the user.
*"Spam-free accessible forms"* - WebAIMs own Jared Smith
Looks at alternatives and provides real-world examples of code - essential
reading (over 2 years old and still utterly relevant)!
http://webaim.org/blog/spam_free_accessible_forms/
*"CAPTCHAs' Effect on Conversion Rates" *- Article by Chenry on SEOMoz
Need to convince the boss not to simply take the "easy" route to spam
prevention? This is an excellent basis for a business case backed up by
results from a study.
http://www.seomoz.org/blog/captchas-affect-on-conversion-rates
*
*I also have a small article "Preventing spam in Web forms without CAPTCHAs"
on my own site. It's a very high level (non-technical) introduction to the
issue and the business considerations surrounding the choice of solution.
http://www.simiusweb.ie/formspam