Accessibility and Visual Literacy

Every child knows that the learning of how to read is hard work. The understanding of graphics is also a skill which must be learned, scientists call it Visual Literacy. This skill is important even when it is not learned actively like reading.

In the issue of accessibility Visual literacy is important because images, diagrams and similar graphics play an important role in user interfaces and content. For some persons for example persons with cognitive impairness graphics can increase the understanding of texts, user interfaces or tables dramatically. In augmentative communication graphics plays a key role.

In this article I want to differ between decorative graphics and content graphics. The latter are important for the understanding of a text or interface, decorative graphics in most cases are a question of aesthetics, and they don't demand much work to understand them.

The visual Literacy is mostly based on passive learning. While growing up children learn to see and differ millions of objects. Sometime parents starts to show the child symbols and tell them, what they mean, for example food packages, pictures in books or in television and so on. Day by day the child learns to understand even complex pictures or objects and their connection to each other like in picture books for kids.

The older they get the more complex the graphics gets. Pupil learns in natural sciences to read and draw graphs or chemic forms. Students of economic science draw complex diagrams like business chains or logistic chains.

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Pictograms and symbols

Pictograms are often easiest to learn. They play an important role in all day activities. They are printed on packages or rule the traffic on the streets. In the best case they are understandable intuitive and inter cultural. When a foreigner visits Germany he should be able to move through the streets without colliding with a car because he misunderstood a street sign.

Many Pictograms are conventionalized illustrations of real objects. You only need a few lines and sheets to draw a wheel chair or a skull.

Other symbols for example for software controlling can be very complex and in many cases have to be learned actively. They were builded on different natural objects and geometric figures. Their task is to offer an intuitive usage of the program.

For users who are experienced in software use it is often easy to learn new symbols especially when they use the program regularly. For newbies this can be quite difficult.

Complex graphics

A more difficult case is the understanding of complex graphics. This can be simple pie charts and ends in complex graphics like info graphics or logistic chains. These objects are constructed of many different objects like geometric figures, lines and so on. You have to see and recognize the several parts of the graphic and parallel the interconnection of multiple objects to get the whole information.

This is a good example to understand better the concept of Visual Literacy. A newbie may look on a logistic chain and only seed a chaos of lines and figures; a logistic expert only takes a look and gets the most important information.

With this we got the two aspects of Visual Literacy
  1. The User has to understand what is pictured - this is the Understanding of content
  2. He has to understand, why it is pictured - this is the understanding of indication

The Combination of Text and Graphic

For complex tasks the combination of text and graphic seems to offer the best solution. There are two possibilities to combine text and graphics.

  1. Redundancy: That means that text and graphic have the same intention. You find this for example in tutorials when you build a furniture from a construction kit.
  2. Complementarity: That means, that the message of the content only can be Understood when you understood both, graphic and text. This you find in comics.

Of course it can happen that text and graphic have totally different intentions but I don't know any case when this does make sense. In practice most content lies anywhere between Redundancy and complementarity.

In principle Redundancy is more accessible than complementarity. In many cases you will have visitors who better understands either texts or images. In complementarity cases you risk that either text or graphic is not understood and the most part of the message get lost. But in some cases complementarity can not be avoided.

A special case is texts in plain language this is an easy form of the conventional language especially for persons with learning or reading impairnesses. Such texts are usually guided by images in most cases simple illustrations. These text-image-combinations always try to be redundant.

Therefore in most cases the combination of text and graphics seems to offer the best solution. The person who does not understand the text perhaps understands the image or either.

Other issues in graphic accessibility

A main rule in accessibility is that no information should be conveyed in only one way. This is especially important for color. No information should be conveyed only through colour or colour change.

It is clear that an appropriate contrast is important. For signs and other symbols it is necessary that they are recognizable in all environments, darkness or in the sun or when the signs are dirty.

Info graphics are almost as famous as cat content but in many cases we may ask if they were understood by the target group. It seems that they were constructed with aesthetics in mind or to show the abilities of the programmer and not with the target group in mind.

The best solution can be to simplify them radically especially to get the interest of persons, who are not experts in this special issue or simply don't spent much time to learn to understand the graphic. You should avoid any element or effect which does not increase the understand ability like 3D effects or colours.

Closed systems and inner logic

As I already showed there are some image systems which constitute a closed symbol language like UML or logistic chains. But they are although examples which plays a higher role in our life. Symbols in orientation systems like in train stations or airports.

There are two factors on which the understanding of those symbols depends:

  1. The experience with these situations
  2. The embedding in special contexts.

The case of experience is clear. When you move every day across an airport you learn to understand where you can find a toilet, the exit or the ticket account.

The context is also clear. In a main station you find other things than on an airport.

I see some problems in big buildings which you visit rarely. Public buildings like authorities can be very complex. Although they can have many visitors they are not constructed in a way in which visitors can orient easily.

Many public services did implement a ticket system. You have to pull a ticket from an automate and have to wait until your number is displayed anywhere in the room. The newbies and persons with disabilities can have difficulties with this.

Different groups can have different problems in the perception of graphics

Blind and visually impaired

persons who have bad sight from birth do not learn Visual Literacy quite well. Therefore it is more important for them that an alternative description does not describe the graphic but its function.

Even for complex graphics a description of the graphic is in most cases not useful. Only persons with a high imagination are able to imagine the constellation of many different objects. For most persons a description of the illustrated process seems to be more useful.

Haptic graphics seems to offer a solution for this problem, but for them there is another problem: Blind persons can only get it step by step, they are never able to "see" the whole diagram. In some cases an accessible table is the better solution.

When a table does not exist or is not practicable it is better to offer a text, in which you describe the most important processes, which are shown in the graphic.

persons, who are born blind in many cases didn't learn the visual symbolic and do not profit from a description of such symbols, even in a tactile form. They learn in school how letters look and perhaps they know for example the form of a car, but it is possible that they don't recognize it when you present it in a haptic way. Therefore the best solution for a haptic presentation of visual symbols is easy geometric figures.

Visually impaired

persons with visual impairness did in most cases learn the visual codes. Their difficulty lies in other factors. In many cases their sight is not sharp enough to get complex symbols with many forms or colours. They profit from easy geometric figures or easy recognizable objects like shears, thumbs and so on.

For humans with disorders in their field of view or very low vision it is difficult to get a whole complex graphic like a map. It is difficult because it contains much different information like streets, environmental elements or other facts.

For visually impaired persons it is helpful when a graphic can be understood step by step. You can help them for example by offering a reading direction which starts in the western hemisphere usually in top left. In maps it does make sense to offer some good visible orientation points like big cities, rivers, great streets or similar. For digital maps and some other graphic types it would great to offer a filter which allows it to switch different informations on and off. This makes it easier to concentrate on special information like shops or mountains for a trail.

Cognitive Disability

With a cognitive disability it is difficult for humans to recognize, understand or remember informations. This group profits most of visual presentations, because in many cases their ability to read "visually" is better than reading and understanding text.

A study of a German organization showed that the ability of persons with mental disability to understand easy symbols which represent of real life is quite good. For example they understand the symbol for bus station, if they see a under stability bus. That they do not understand are combined or abstract symbols. For example, a human going on a stairway for stairway or "WC" for toilet.

Texts in plain language should be guided by illustrations to increase the understandibility. The information ideally is coded textually and graphically. That is not possible in all cases. Graphics are most useful in cases where we have strong conventions or where they are under stability images of real objects.

Testing graphics

Complex graphics and texts have in common, that they can not be tested automatically like image contrast. You need a lot of experience or a second mind or both to check the understandibility of a graphic. For graphics for a broader audience it is necessary to make usability tests.

Information graphics had a big hype for example in data journalism. But the makers ask not enough, if their graphics are understandable for some persons. Most web editors are concentrated on texts and decorative graphics. Critics foremost illustrators say that web editors decorate instead of illustrate and this is quite true. Many web editors have low experience with drawing applications and think that it is better to avoid graphics than to offer a bad drawn.

That is okay because of our wish to offer a high quality but it is not good reason to avoid the learning of drawing skills. With the new tools and the increasing requirements of our audience we have the duty to choose the best tool to provide our information or message instead of using the one we have.

Further Reading