Wednesday, February 12, 2003

Bad Ergonomics: Elevator Control Buttons

Bad Ergonomics: Elevator Control Buttons
[人因工程 ]

Bad Ergonomics: Elevator Control Panel

This is the control panel of the lift (elevator) in our department. The first time you order a lift you'll definitely push on one of the top arrows. However, these arrows only indicate whether the lift is moving and in what direction. To order a lift you must use one of the lower buttons with the text "op" (up) or "neer" (down). Indicators and controls have exactly the same appearance here.

Editor's Comments:

Mention the word "ergonomic" and what comes to mind? If you're like most people, you immediately think of the countless "ergonomic" mice that "fit the hand" or "ergonomic" keyboards that look like they were sawed down the middle then glued back together at an angle. But in fact much of what makes an industrial product ergonomic or nonergonomic has little to do with what it feels like, and a lot to do with what it looks like.

Yes, the problem is that the UP and DOWN indicator lights were given the three dimensional shape of control buttons. But what makes the elevator control panel nonergonomic is not how these indicator lights FEEL, but rather how they LOOK. It is the LOOK that causes users to reach for the indicator lights instead of the control buttons. Its negative ergonomic characteristics impact the user long before the user's fingers touch the control panel.

The most misleading aspect of the look is of course the articulated grooves surrounding the arrow symbols. These grooves make the flush-mounted indicator lights look like control buttons that can be actuated by pushing on them.

A second possibly overlooked factor is graphic symbols are far more powerful than written text. Arrow symbols which POINT up or down speak louder than strings of text which spell out "up" or "down". Exceptions to this rule might be Egyptian hieroglyphs and Chinese pictograms, which are essentially ancient versions of internet browser icons.

Finally, the designer of this elevator control panel compounded his error by making the control buttons horizontal rectangles, while making the indicator lights vertical rectangles. The vertical axes of the indicator light rectangles only serve to strengthen the grossly misleading impression that the indicator lights are control buttons dedicated to controlling up and down movement. That the control buttons look as if they were squeezed in at the bottom of the panel as an afterthought, instead of occupying the favored central position on the control panel doesn't help either.

How might this design be improved for future production runs? One solution out of many would be to simply eliminate the two control buttons at the bottom of the panel, and redesign the indicator lights so that they are not just indicator lights, but also control buttons. The indicator lights already look like control buttons. Why not go ahead and actually make them control buttons, with indicator lights integrated into their surfaces?

-- Bevin Chu

Explanation: Bad Ergonomics: Elevator Control Panel
Illustration: Elevator Control Panel
Author: Werner Vogels
Affiliation: Human Factors and Ergonomics Society Europe Chapter
Publication Date: 1998-1999
Original Language: English
Editor: Bevin Chu, Registered Architect

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