Thursday, February 20, 2003

Bad Ergonomics: Press GO to STOP

Bad Ergonomics: Press GO to STOP
[人因工程 ]

Bad Ergonomics: Press GO to STOP

This example is taken from a European project called SAVE. Imagine that you drive a car that can take over control in case of an emergency, e.g., a cardiac arrest. To be sure, the system asks whether it should take over control, but it does so in a complex way.

Apart from being hardly audible, the text is difficult to understand. Literally the metallic voice says:

"It is supposed that you have severe problems to drive. If you do not want an activation of the autopilot, press the Confirm button."

Naturally a "Cancel" button should have been used, because that is what happens if the button is pressed: the action is cancelled.

Actually, I must say that the SAVE project is not bad at all. I worked on it, so how can I say bad things about it? But errors are made everywhere. I also believe that in the end this text was changed.

Editor's Comments:

The editor has cited numerous examples demonstrating why the term "ergonomic" must not be equated with "form-fitting" or "tactile". To do so debases the term. The sense of touch is one of the factors in Human Factors Design, but hardly the only factor, and often not the primary factor. The sense of sight is usually the first sense engaged in any Man Machine Interface, and as this example demonstrates, hearing runs a close second.

Let me be clear. The designers' less than perfect English grammar is not the problem. We are addressing design, and ergonomic defects transcend language. The problem is a failure to appreciate the life or death importance of clarity to industrial design.

The sentence "It is supposed that you have severe problems to drive", while awkward in its construction, is nevertheless understandable. This is not the problem. The problem is the second sentence, "If you do not want an activation of the autopilot, press the Confirm button."

Consider the way the choice is put to the user. "If you do not want an activation of the autopilot, press the Confirm button." The designer is saying "If you do not want something, confirm that you do not want it." Only not so clearly.

The product designer is demanding that the driver of a moving vehicle, possibly undergoing cardiac arrest, barreling down a public highway, to clear his head, unravel the designer's double negatives, then make a decision about whether or not to press a button, a decision which may or may not end his life.

The designer might as well ask the driver to play Russian Roulette with a double-barreled shotgun.

Obviously this has nothing whatsoever to do with foreign language skills, and everything to do with the fact that the product designer was not thinking clearly in any language.

How should the designer have worded the message? How about:

"If you can drive, press OK."

Wording the instruction in this direct and intuitive fashion is the linguistic equivalent of "natural mapping" in physical space. The positive state "can drive" is mapped to the positive affirmation, "OK". Positive is mapped to positive, just as when an electrical circuit is turned ON, the power switch reads "ON". This allows a user to understand his situation and react spontaneously, without hesitation or delay.

Other possibilities come to mind. The exact wording is not critical as long as the meaning is clear. The bottom line, as always, is "KISS". For those unfamiliar with the expression, it means "Keep It Simple, Stupid!"

-- Bevin Chu

Explanation: Bad Ergonomics: Press GO to STOP
Illustration: None
Author: Dick de Waard
Affiliation: Human Factors and Ergonomics Society Europe Chapter
Publication Date: 1998-1999
Original Language: English
Editor: Bevin Chu, Registered Architect

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