Creating accessible websites for users with learning and cognitive disabilities is an area with little research and few concrete recommendations. While web developers can apply universal principles of web accessibility to benefit all users with sensory or physical disabilities, the application of cognitive accessibility is varied and complex. Due to the limited research and complexity of cognitive web accessibility, common techniques to increase usability for those with cognitive and learning disabilities are hard to come by, despite the fact that the number of users with these disabilities far exceeds the number of people with other types of physical and sensory disabilities.
WebAIM, through a Steppingstones of Technology grant (U.S. Department of Education), has undertaken a project to assist web developers in creating web sites that are highly accessible to users with cognitive and learning disabilities. The goals of this project are to research recommendations and expert opinion on cognitive web accessibility, test the impact of selected recommendations, implement a set of best practice rules into evaluation tools, and report on our findings. Our goal is to implement and report on real strategies that web developers could implement to increase the accessibility of their web pages.
WebAIM conducted a thorough文献评论and then filtered expert recommendations to identify key aspects of design that are broadly applicable, of benefit to web developers, and machine testable. The test items had high effects on the largest number of people with cognitive disabilities, were very useful for web developers, and could be automatically tested. The resulting list of items was tested with users with cognitive and learning disabilities:
- Font size
- Reading level
通过测量效率，准确性和满足来测试上述每个项目，在完成基于Web的Web页面上孤立测试项目的网页上。例如，一个页面可能具有足够的字体大小，而另一个页面可能具有小字体大小。其他变量（Distrack，阅读级别，复杂性，随机性等）被占 - 换句话说，我们尝试使页面之间唯一不同的是我们测试的元素。
We tested one page that had small font size with a page that had slightly above average font size. Seven of the eight volunteers were more efficient (correctly found relevant information) with the larger font size than average font size. Larger font size appeared to have a positive affect on effectiveness (they found the information more easily) and user satisfaction (they indicated that the larger font page seemed easier or was more efficient).
We tested one page that had images corresponding with the text and another without images. Seven of the eight volunteers were more efficient and seven of the eight were more satisfied with the inclusion of images.
We tested three pages with different line lengths: short (~25 characters), average (~75 characters), and long (~120 characters). The difference in efficiency between an average line length and a short line length is inconclusive. However, the pages with both average and short line length were dramatically more efficient than the page with a long line length; all 8 students took the longest time to interacting with long line lengths. Despite being the same length, some students commented that the length of the pages appeared different - with the longer lined pages being shorter. In other words, while some students perceived the long line length page as being shorter than the others, it actually took them much longer to read it.
We tested one page with video instructions against a page with written instructions. Seven of the eight students were more efficient and also expressed more user satisfaction from the page with the video instructions than the one with written instructions.
Tests on the following items did not appear to significantly impact student performance. Please keep in mind that we worked with a small number of students. Greater participation might have changed this result.
- 标题- one page with headings against one without. Students were slightly more accurate, efficient, and satisfied with the pages that did not have headings. The succinctness of the page content may have caused the headings to be more of a distraction than a benefit to some students.
- Lists- one page with a list against one without a list. While there was little difference in accuracy or efficiency of completing the task (see observations below for insight into this), students were much more satisfied with the page that contained the list and indicated that it seemed easier.
- Reading level- one page with a higher reading level and one with a lower reading level. While students completed the tasks slightly more efficiently with the higher reading level page, there was no difference in accuracy or indicated satisfaction. Again, the sample of text was not sufficiently large to gain a highly accurate measure of reading speed.
- 搜索- the ease of finding a web page in a site—once with search and the other time with click-through navigation. There were varied results to this test. Spelling out the search terms proved difficult and time consuming for some participants. Others had difficulty choosing ""the best" search result from the list. Some students had difficulty completing the task without search (see observations below).
- 字体类型- one page with serif type against one with sans-serif type. The difference in reading speed and satisfaction between serif and sans-serif fonts was very small.
在许多方面一般observations we made while testing the students were just as, if not more, valuable and surprising than the measurable data we collected in each test.
页面的感知难度可能对参与者实际难以进行直接影响。例如，几乎所有学生都比具有较大字体与具有较小字体的页面更高效，更满意。但是，学生评论说，具有较大字体的页面更容易，因为它们包含较少的文本。实际上，这两个页面都有相同的单词数。较大的字体大小使页面似乎具有更少的文本 - 学生表明这些页面是易于实现的原因，而不是因为它们具有大字体。因此，很难隔离是否是字体大小，实际上是任务完成效率差异的字体大小，或者如果是学生对差异的难度的看法。
Confirmation for confidence
One example of this occured when testing the "search" item. Our preliminary research indicated that the presence of a search mechanism should be helpful for our target users. Some students, however, found it overwhelming when they engaged in a search and were presented with numerous search results. They showed difficulty and apprehension in choosing the正确的page from those search results. As a result, while utilizing "search" as a design element was easier, the efficiency of completing the task was affected by the efforts of the student to accomplish the task accurately. It wasn't a matter of finding the correct answer, it was a matter ofchoosing正确答案。以更少的压倒和更直观的方式提供结果，为用户提供从错误中容易地恢复的机制，并使任务的结果可能影响完成任务的实际效率。
Lesson learned: Simplicity, error recovery, and intuitiveness can increase efficiency and confidence.
大多数开发人员意识到具有某些认知或学习障碍的人可以很容易分散注意力。通常的嫌疑人 - 广告，闪烁的图像，非常亮的颜色，高对比度等都很明显。避免的难以分散越来越困难的分心也是那些也是学习艾滋病的分心。
In most cases, as was seen in our study, multimedia can be an immense help, especially in cases where instructions are hard to describe. However, the use of multimedia can introduce other issues. Some students appeared to be rushed or unable to keep up with the video instructions in the multimedia test case (tying a knot via text instructions or via multimedia demonstration).
Lesson learned: A text alternative, a prominent pause feature, and an ability to quickly rewind or replay the video allow users to use multimedia to go at their own pace and take in all of the information.
Consistency and organization
Two examples of consistency and organization affecting cognitive accessibility were unexpectedly discovered in our testing.
During one test, students were asked to find a page about hockey. The hockey link—found on the sports page—stood out and was very visually significant from all other links on the page. It was styled dark blue with light text instead of black text on a light green background and had a very prominent picture of a hockey player.
在大多数情况下，造型差异可能使曲棍球链接似乎消失，也许是因为它与其他运动链接不一致。曲棍球按钮上的特殊样志似乎具有相反的网站作者的意图（就我们的用户具有认知残疾人而言） - 而不是引起关注链接，因此它使得这些链接不那么明显缺乏一致性。在某些情况下，仍然没有找到此链接，尽管是在风格上是页面上最突出的链接。
Lesson learned: Sometimes making something more visually obvious also makes it so much different that it can be difficult to find.
Lesson learned: While organizational elements (headings, lists, etc.) can help accessibility, they should be clearly differentiable from other elements.