Bad Designs: Lamp Switch

Bad Designs: Lamp Switch
[人因工程 ]
(2003/02/10)



Bad Designs: Lamp Switch

This picture shows the switch on our halogen desk lamp. It is a three-position rocker switch. Its three positions are

low (I)
off (O)
high (II)

To switch from low to high or vice versa, you have to move the switch through the off position. I wonder why it works likes this? Wouldn't it make more sense if its three positons were

off (O)
low (I)
high (II)

That way you wouldn't have to first turn it off to switch from low to high. It seems like a more natural order. One other problem with this design is that it is difficult to tell when the lamp is set to high vs. low because it turns completely off between the two settings.

Design Recommendations:

The order of the settings on a control should be natural. You shouldn't have to move a control into the "off" position to move it from one level to the next.

Editor's Comments:

Michael Darnell, author of www.baddesigns.com is right to challenge the above mentioned design. It is counter-intuitive in the extreme. "I wonder why it works like this?" he asks. We can hazard a guess. Almost certainly the designer of this badly conceived light switch thought to himself, "If I put the 'off' position in the middle, establishing that as a neutral point of departure, then users need only flick the switch one way to turn the lights to 'low', or the opposite way to turn the lights to 'high'. Think of all the wasted motion saved!" The only problem is, this sounds better in theory than it actually works in practice. Because of its counter-intuitive layout, far more wasted motion has surely been expended by baffled users clicking this switch back and forth repeatedly struggling to figure the switch out! Defective designs such as this wind up in production because designers are so enamored with the idea of how their designs ought to work, they don't bother to make sure that's how they actually work.

-- Bevin Chu

Explanation: Bad Designs: Lamp Switch
Illustration: Bad Designs: Lamp Switch
Author: Michael J. Darnell
Affiliation: Bad Human Factors Designs
Source: www.baddesigns.com
Publication Date: 1998-1999
Original Language: English
Editor: Bevin Chu, Registered Architect