Chinese Man Declared The Tallest Naturally-growing Human By Guinness World Records © Getty Images.
How would you describe yourself? Would you say you had some striking features or do you think of yourself as a average sort of person? In this session you will find out just how "average" or "special" you are.
As we've seen, this module is about the design of digital resources and in it we are going to adopt a particular approach, known as "user-centred design". We actually have to think carefully about who our users are going to be and then take the trouble to find out useful things about them. What are their interests and how will our site help them? How do they think? How do they search for information?, What information do they want? What are they going to do with it? This approach to design is called "User-centred" to distinguish it from other approaches which tend to focus on the thing to be designed rather than the users of that thing. One mistake that is commonly made is to design for the "average" or "normal" person. This session is about understanding what we mean by "normal". In it you are going to do a practical exercise to find out how normal you are compared with (a) the rest of your group, (b) people generally and then reflect on what this means for how things should be designed.
By the end of this session you should be able to:
- Explain what is meant by the "average fallacy".
- Explain why it is unreliable to base design decisions on notions of what is normal.
The fallacy of the average person
In an experiment designed to find out just how average people are, Daniels and Churchill (1952) categorised 4063 men (note, men only) according to 10 simple measurements such as standing height, shoulder, elbow height, arm length, sitting height, leg length, etc.. Not one was average in all 10 dimensions and fewer than 4% were average in even the first three. The experiment demonstrates clearly that there is no such thing as an average person. It is a fallacy. These were just simple physical dimensions, but people vary in all kinds of other ways too. For example the way we see things varies depending on our colour vision and visual acuity (how many people in the group wear spectacles or contact lenses or are colour blind?). And it's not just how we perceive data, its also about how we process it and assimilate it and remember it. Different people presented with the same picture will observe different things in it, depending on their interests, knowledge, surroundings, previous experiences, cognitive styles, etc. The same thing happens when you present people with Web pages, magazines, catalogues and so on.
But if there is no such thing as an average person, then we can't design for the average when we want to present some complex information such as an exhibition, or a catalogue, or a research database. Secondly it means we can't rely on our own judgement about what will work. The idea that "this works for me, so it should be OK for other people because I'm pretty average" is commonly held, even among designers. But if we all differ from the average in so many ways then what works for me is quite likely not to work so well for you. So what can we do about it? Well, there are several ways out of this dilemma. Positivist approaches such as Anthropometry, Psychology and other sciences advocate systematically collecting and analysing information about large groups of people using statistical techniques or conducting controlled experiments with carefully selected, representative, samples of users. Both these methods tend to be expensive and time consuming (although they produce very reliable data when done properly). A more pragmatic approach, which we are going to use in the next session, is user-trials.
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