Traffic Lights and my Keyboard - Back to the very basics of ergonomics

Generally, in Western Culture

Generally, red is used to mean "stop" or "danger," green to mean "go" or that

the system is running normally, and orange to signify "caution" - Introduction to ergonomics, Third Edition By R.S. Bridger

Double signals.

To ease the creation of the mental maps, some interfaces double the signals for the users. A well-known example is the traffic light. Easy to color-blind people, the signal resides both in the position and in the color.

The classic traffic light: the signal to stop is communicated by both the position and the color (in the western culture red is used to mean "stop" or "danger").

The more signals you add to convey the same message, the clearer the message. For pedestrian traffic lights, it's commonly used a system with three coherent signals: color (red for stop, green for go), position (top for stop, bottom for go), shape (a man walking, walk, a man standing, stop). 

A traffic light for pedestrians: you can note that there are three signals to convey the same message: position, shape of the man, color. An excellent system.

 Now imagine a system using more than one signal, both misinterpreting the standards: a traffic light for pedestrians where the standing man is green, the walking man is red. Confusing, isn't it?

My bluetooth keyboard: using the wrong signals?

If red is danger and green is "ok", how do you associate red with the two possible states of a battery operated keyboard? Here are some examples

• Battery: red is danger, you are consuming it, green is ok, you are not consuming it.
• Operations: green is ok, you are good to use it, red is danger, it doesn't work because it's switched off

It's easy to understand that you cannot universally code two universal signals for western culture, because it is a matter of interpretation. Person A would interpret green as "keyboard operational", while person B would interpret green as "keyboard switched off, the battery is safe". Worst, the same person could use interpretation schema A on saturday, and interpretation schema B on sunday, for his own dazzling and confusion.

My bluetooth keyboard, what does green mean? Is it swtiched on? Is the battery safe (keyboard off)?

My bluetooth keyboard, what does orangemean? Is it swtiched on? Is it off? The switch is close to the "Off" sign. The color is close to the "On" sign.

 

The problem with multiple cohesisting signals 

The problem with multiple cohesisting signals is that the message they convey must be coherent and based on single universally acquired interpretations in the schemas of the referring culture.

I doubt who designed this simple switch didn't study ergonomics.