> I'd suggest you do a Google search
> on the human ability to discern colour
> as an indicator way faster than reading text.
"In psychology, the Stroop effect is a demonstration of interference in the reaction time of a task. When the name of a color (e.g., "blue", "green", or "red") is printed in a color that is not denoted by the name (e.g., the word "red" printed in blue ink instead of red ink), naming the color of the word takes longer and is more prone to errors than when the color of the ink matches the name of the color.
...
This is based on the idea that word processing is significantly faster than color processing."