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Lucy Greco

Accessibility in Education


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07/27/2012

Reclaiming CAPTCHA for Persons with Disabilities


CAPTCHA is an important security feature to keep spammers in check. However, image, audio or text CAPTCHA are not wholly accessible for persons with a range of disabilities and keeps this very important demography off the information highway, says Lucy Greco.

In 1997, the Internet was starting to show signs of what it would become. More people were logging on every day and with that, others were starting to find ways to make money off of this information highway. Today, over 80% of the e-mails sent are spam, but fortunately, more ways to fight spam are being developed. In 1997, Alta Vista was the first company to create the CAPTCHA to fight this flood of unwanted Internet traffic. This first block was to help prevent hijacking of search results that made it impossible to search accurately.

Image of a typical CAPTCHA text cue

Image of a CAPTCHA text cue featuring distorted letters

Perhaps I should first describe what a CAPTCHA is. Here is the definition as found on Dictionary.com: “An online test that humans but not computers are able to pass, used as a security measure and usually involving a visual-perception task.” However, many sites have alternatives for people who can’t use the visual method to continue past the image that features alphabetical or numerical cues. Websites also use an audio CAPTCHA as an alternative to the image. One of the most popular spam control feature is reCAPTCHA. This is a free service that provides the image and the audio files for a site. reCAPTCHA then uses the results of the inputs to help identify the images of text while digitizing them. Earlier, they also provided clips of movie sound bites to help caption older titles. However, today the sound bites are synthesized speech, with distorted speech overlaying the synthesized words.

The CAPTCHA strategy has resulted in problems for many people with disabilities. Obviously the images cannot be read by a screen reader. If they could, it would defeat the purpose of the CAPTCHA’s property of being readable by people but not by computers. This is why audio CAPTCHA was implemented. People often can’t solve CAPTCHA for a growing variety of reasons. For example, I have not been able to solve a reCAPTCHA audio-CAPTCHA for two months now because they have made the audio harder to hear and added a lot more words to solve. I can’t understand half the words in the sound clip and my spelling is so bad that I can’t spell the other half. It’s interesting how an audio CAPTCHA is automatically harder to solve than a visual one. For example, reCAPTCHA gives an image of two units, like words, but the audio version has many more words, sometimes up to ten or more.

A sighted person can compare and contrast what they’re typing to the letters shown on the screen, but an audio user must try to distinguish between unintelligible words, such as “there” or “their” or “they’re”. There is no memory needed for the sighted user in solving the CAPTCHA, but the listener must remember as much as they can of the audio file to be sure they get it all.

I tend to type and listen to the words every time I hit the space bar, but as a blind user, if I’m trying to solve a CAPTCHA, I run the words together so that the screen reader doesn’t speak at the same time as the synthesized voice I’m trying to hear from the CAPTCHA. I don’t know how many times I’ve had to try over and over again because I missed one word and don’t remember what it was. And if I submit it and it’s incorrect, then I start all over again. The only thing that is more frustrating is a site that doesn’t provide me with an alternative.

Many people with cognitive disabilities can’t use the visual CAPTCHA either. If they have a reading disability and the image of the text is distorted, they may never be able to read the CAPTCHA at all. Many of the students I worked with, who have learning disabilities could not use the best synthesized voices on the market. They were not able to understand words spoken in a computerized voice. Some of these students would not be able to use either image CAPTCHA or audio CAPTCHA.

Over the past few years, people have been trying various ways to change how CAPTCHA behaves. Some people have switched to challenge-questions instead. The problem is that the questions must be so generic as to be solvable by people from other cultures. For example, if a challenge-question asks,  “What comes first: dinner or supper?”, some people may not know the word supper at all. Others may think the two words mean the same thing. Very few people recognize that dinner is another word for lunch in some parts of the world.

I understand the necessity of CAPTCHA in most cases, but we really need to find other ways to get past the money and down to work. I would never want the Internet to get more disrupted by the traffic that CAPTCHA is blocking today, but I do want to use the tools and applications that CAPTCHA prevents me from accessing.

I remember working on the problem with Annualcreditreport.com a few years ago. When we found a way to make the reports accessible, we then needed to find a way to get to them. The only way we could come up with was to use an extra form of communication. The person who was unable to read the image to solve the CAPTCHA would have to click an additional link that would then bring up a phone number to call and a code to give the computer on the other end. The computer would then give you the appropriate answer to allow you to respond to the challenge. This is problematic, since it relies on a having access to a phone. But the system worked for most people.

The real answer is that we need to stop the effectiveness of spam. We get so much of it that we need ways to block spammers’ access to the web, because somehow and somewhere people are falling prey to it. Spammers will keep trying to send ads if we all keep clicking on the links. If you find a link that looks somewhat legitimate, it’s hard to say, “Well, maybe it’s not worth checking.” I know I often do it myself. The sender’s name is one I think I know and I am interested in the subject, so I check. I get a message saying I will get a free iPad, so I fall for it. I know better, but the spammers also know we all want something and they offer it and we take it.

The only other thing that can help us tackle this issue is international consensus on not letting people get away with it. With electronic borders that don’t really exist, phones and the Internet, spammers just need to simulate an address off-shore to bypass laws created to stop them. Also, we need to teach people how to identify the fakes and how to be smarter about what they open or click online. We need to make sure we know the sender of an email and how to tell what the consequences of replying to spam are. Education is the only way we can cut back on this hostile takeover of our information highway. When it comes to the Internet, we really are a global village, so let’s start keeping our village clean and inviting to all.

Lucy is a blind advocate for accessible technology. An Assistive Technology Specialist at UC Berkeley, San Francisco Bay Area, Greco is the user of various assistive technologies since the early 1980s. She is passionate about the ways technology makes the world more accessible to everyone but especially to individuals with disabilities.
 
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Related Blog: The Accessibility of the User Interface by Lucy Greco | Read the blog.
 
Related Publication: Benefits and Costs of e-Accessibility - a G3ict Publication | Order your copy here.
 
Related Event: Workshop on IT for Disabilities (IT4D'2012) at Wroclaw, Poland on September 9-12, 2012 | Event details here.

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Related Items:

• Making Advanced Technology Useful for Independent Living for Disabled People at Home

• MODEL DIGITAL ACCESSIBILITY POLICIES PRESENTED AT THE UNITED NATIONS

• Inaccessibilty of CAPTCHA 2 via W3C

• Press Release from Council of Canadians with Disabilities

• IAAP March Webinar: Captioning and Audio Description Technology and Best Practices, Online Event


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