Mental models
For a few minutes of comic relief, I love catching up with the latest posts on clientsfromhell. Some of the stories are scarily familiar and others just plain terrifying. But there’s a category of story that is amusing because it misunderstands something so familiar to us as “computer people” that they make us see the things we do in new ways.
Similar to the story of the user who thought his PC CD tray was a cup holder, these misunderstandings betray a unique way of seeing computers that are amusing because they are jarring. What these misunderstandings help to reveal is a user’s “mental model” of how a computer or website works. Take these recent examples from clientsfromhell:
Client: “Can you please confirm that you are Web 2.0 compliant so that we cannot be sued for discrimination by law?”
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Designer: “The password is ‘123456’.”
Client: “Upper or lower case?”
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[Client sent Designer some complex logos (as JPEGs) in order to vectorize them.]
Client: “What exactly is taking so long? If I knew it would take so long, I’d have done it myself.”
Designer: “Vectorizing the logos takes some time because—”
Client: “Time? Renaming files from *.jpg to *.eps takes time?!”
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These stories could just be dismissed as simple ignorance of course but I think they show a way of thinking that has gone slightly astray – the client has a different mental model of how websites or computers work and this leads to some amusing results.
So what do we mean by “mental model” exactly? This from Wikipedia:
“A mental model is an explanation of someone’s thought process about how something works in the real world. It is a representation of the surrounding world, the relationships between its various parts and a person’s intuitive perception about their own acts and their consequences.” http://en.wikipedia.org/wiki/Mental_model
We use mental models to help understand the world around us. They allow us to operate with objects in space so that our actions can bring about predictable results – it’s when our actions cause unexpected results that frustration occurs. However, with luck, we can learn from the unexpected result and use that new information to refine our mental model. When you’re learning to open a door, the feedback you receive is immediate, physical and obvious. When you’re dealing with computers however, the objects you interact with can’t be known in the same way.
Key characteristics
Mental models have a few key characteristics.
- Mental models include what a person thinks is true, not necessarily what is actually true.
- Mental models are similar in structure to the thing or concept they represent.
- Mental models allow a person to predict the results of his actions.
- Mental models are simpler than the thing or concept they represent. They include only enough information to allow accurate predictions.
A quick example
At home, we have a great power shower. The water is hot within seconds and the stream of water is powerful enough to wake you up no matter how tired. The only problem had been trying to set the temperature.
Looking at the graphics printed on the shower unit, it seems fairly self-explanatory that to get hot water you aim the marker at the red ovals. To reach this conclusion you take information from a number of internal models; ‘taps rotate to turn on water flow’ and ‘red is hot, blue is cold’. And from there it only takes a quick leap of imagination to assume that turning the dial to point at the red dots will result in hot water.
And if you do aim for the red dots, you do indeed get hot water. So far, so good: your mental model is in place, you’ve tested it (turned the dial), and the feedback (hot water) apparently confirms your model. You guessed correctly and you’re now standing underneath a stream of hot water. However, coming back to the shower on a hotter day, you decide you want cooler water. Based on your ‘experiments’ so far, you might reasonably turn the dial to the blue dots in order to cool down. Unfortunately, on this occasion, you actually get much hotter water; your mental model breaks and washes away with the soap.
So what went wrong? Your mental model predicted an outcome and after one test result the model stood up well. Unfortunately, the model was actually technically inaccurate so that when you tried again, your predictions failed.
The shower unit actually regulates temperature by changing the flow rate of the water. The faster the water passes through the unit the colder it is because it’s had less time to warm up. The slower the speed at which the water passes through, the hotter the water.
This very simple piece of information turns your model on its head. Now, instead of aiming at dots, you control the speed of the water and you’re able to control the temperature much more accurately. With this knowledge, you then start to see the graphics more as arrows – the thickest red dot is the head of the arrow pointing to the left, and is saying “turn this way for hot water”. Possibly if these designs were more ‘arrow-like’ their information would have been conveyed more quickly?
Relevance to web design
Mental models can be used by thoughtful designers to make a visit to a website more comfortable and less frustrating. Clicking on similarly styled links should have the same result as learnt at other sites with similar looking links. Clicking on form buttons should result in similar outcomes as has been learnt at other websites that have form buttons. Design standards and patterns are useful because they allow users to build up a mental model of how a website works. Breaking these conventions frustrates the user because it weakens their mental model. Do it at your own risk!
