Captcha usability revisited: Google inaccessible to blind people

An online petition is being circulated to all Internet users for the purpose of collecting signatures showing support for Google to make its word verification scheme accessible to the blind and visually impaired.

I just signed up for the request to make Google more accessible. (I’m number 2759 on the list), and you can sign it too.

We, the undersigned, ask Google Inc. to “do no evil” and follow their mission statement to “organize the world’s information and make it universally accessible and useful” by promptly adding accessibility to their visual word verification scheme so that the blind and visually impaired are allowed to fully participate in all products and services offered by the company on terms of equality with our sighted peers.Sincerely,

The Undersigned

What Google does wrong

The problem is that it requires vision to see what’s the word/text in the word verification (captcha). Purpose of captcha is to tell machines and humans apart, and can prevent machines from creating accounts that for instance spammers and phishers can abuse. More about captcha Wikipedia.

Here is what Google does in the sign-in process:

screenshot of the google account signup captcha

Clicking on the wheelchair icon reveals a popup-window that shows the same image in a separate window.

The press release from Blind Access Journal tell us that this is wrong and will block blind users, because it…

…currently locks the blind and visually impaired out of participation in all the company’s services. Google’s implementation of word verification currently denies us access to such important features as the ability to create accounts and blogs, change our passwords, and post comments to most blogs that use the Blogger service. Accessible solutions to visual verification have already been put in place by such companies as America Online, Microsoft, PayPal and SpamArrest.We ask Google to follow this lead with an audio playback implementation now, followed by the creation of new innovative approaches that meet the needs of all users, including the deaf-blind population.

What Google should do

Recently, Peter Kranz of Standards Schmandards wrote a terrific overview different accessibility problems with captcha and came up with a proposal for an accessible captcha.


Some of the solutions proposed in the W3C article are:

  1. Use logic puzzles. This solution does not satisfy requirement 2. It would require someone to manually create these tests. Also, they would probably be difficult if you have a cognitive impairment.
  2. Use credit card validation. Brilliant idea. Everyone would be happy to submit their credit card number to unknown sites on the internet.
  3. Live operators. Fails on cost efficiency. Although it would be one of the best ways to provide support for your users, a lot of sites do not have the resources to provide this kind of service.
  4. Federated identity systems. Well, this does not exist yet so we can not use it.
  5. Sound output. If it could be possible to create a sound file that was difficult to decode for a machine, this may be the best option to use together with a regular captcha image. Let’s move forward with this solution.

First of all I suggest that you thoroughly evaluate why you need a captcha. Is it really necessary? A lot of sites implement them because it “looks professional”. If you can avoid captchas, please do so.

My proposed solution is based on an ordinary captcha image in combination with an audio based test. Instead of providing the same information in the audio file as in the test image (like the Hotmail registration form) we will use a separate test. This test is based on the ability of the human brain to understand the meaning of information as well as discard unnecessary details.

An audio file as an alternative to the image. And this is exactly what Blind Access Journal proposes in the text for the petition. If you want to help, I think you can help both Google and blind internet users by signing the petition.

11 Responses to “Captcha usability revisited: Google inaccessible to blind people”

  1. Consuelo Puchades Says:

    Really interesting! It is sometimes difficult to mix accesibility and security, at least this is the excuse that techies often use in projects.

    We had some problems with pinpad access to sign in banking transactions. Changing it was considered bad for security, and though they are working in a solution which increase security, it has not been implemented yet.

  2. | Blog usability: Avoid spam comments Says:

    […] A non-machine readable image or similar. We probably won’t use that, because most implementations have accessibility issues to disabled users. See our ealier “Captcha usability revisited: Google inaccessible to blind people” […]

  3. Jesper Rønn-Jensen Says:

    Accessibilityblog has a rant “Circus of CAPTCHA’s, where Matt rants Yahoo!, Digg and MySpace because they provide no alternative to the graphic captchas. There is a very interesting comment that caught my eye:

    There’s absolutely no reason why CAPTCHAs have to be graphic-based, except that it’s easy. Asking the user a simple question based on the content of the site (”What is the name of this blog?”) or something that requires them to interpret a question (”What do the letters B, L, O and G spell?”) will usually do the trick. If everyone has unique questions on their own blogs, it’d make it very difficult for spammers to collect and submit the right answers automatically.

    (comment by Kirsten, “Crows to burnaby)

  4. | CAPTCHA usability: Humane alternative to CAPTCHA Says:

    […] So, much of this is learning from usability: Stop hurting the users! There are so many problems with traditional CAPTCHAs described already by me, Roger Johannson, Peter Krantz, Michael Mahemoff, Bob Easton, Christian Heilmann. […]

  5. | Google Release of Audio Alternative to CAPTCHA Says:

    […] Interesting that they changed the meaning of the wheelchair icon. Back in January when I wrote about Google being inaccessible to blind people, the wheelchair just symbolized a popup version of the same image. Original Google CAPTCHA as described in Captcha usability revisited: Google inaccessible to blind people […]

  6. 15 minutter » Blog Archive » Debat på Dagbladet information - kun for seende Says:

    […] at bruge captcha-metoden til at stoppe en overflod af spam på sitet. Men som Jesper Rønn-Jensen tidligere har påpeget, så kan den slags desværre ikke bruges af […]

  7. Como Emagrecer Rapido Says:

    Man! Spammers make up some difficult problems! I think a sound captcha would be easier to “crack” than an image one.

  8. Voos Baratos Says:

    Its a very important point you bring up. I have never seen a blind person use a computer before and I think it is great that these issues get attention.

  9. Cartao de Credito Says:

    That is a good point that you bring up! I think google should make this better!

  10. Algarve in Portugal Says:

    I agree with you on this, but sometimes it is hard to balance things out. If you make it too easy then someone can program something to break captchas, if you make it to hard its inaccessible to some people!

  11. Ken Moses Says:

    Captchas do not work for people with impaired vision on public-access (library) computers which have the sound permanently disabled. And they are too often used to block access for new users who want to ask questions that are not covered by FAQs. It’s especially frustrating when the telephone numbers do nothing but refer to a web site. Dial-up users are also stymied by the endless load times of overly-bloated web pages. It goes on…