(classical music)
- Okay, no messing around,
because I know you are in a hurry.
Today's Brain Stuff question is,
why are stop signs red?
Why not green or purple?
Why not mango tango or tickle me pink?
Well, in the early days of motor vehicles,
the rules of the road were,
let's say they were really
more what you call guidelines
than actual rules.
Believe it or not, the
first stop signs in America
were not put in place until 1915.
When those much needed first stop signs
finally did show up,
it happened in the motor
capital of Detroit, Michigan
and they were not the red
octagons we know and love today,
but were white squares with black letters.
Now, traffic sign codes
throughout the twentieth century
have recommended several
different variations
on the basic design.
For example, in 1935,
the United States got its first official
Manual on Uniform Traffic Control Devices,
or MUTCD, which said stop signs
should be a yellow octagon
with black or red lettering.
It wasn't until the 1954
revision of the 1948 edition
of the MUTCD that the red
octagon with white letters
became the law of the land.
According to that document,
the red color is consistent
with the accepted use
of a red light as a stop signal
and of the color red as a
special warning of danger.
Furthermore, they explained
that the original decision
to use yellow instead of red
was because red pigments were more likely
to fade away over time with
exposure to the elements.
However, by the 1950s,
the state of California
had solved the problem
by using porcelain enamel
to protect their precious red signs
and higher durability red paints
were becoming more widely available.
And like that, red became the new yellow.
But, there's a question that goes deeper
than uniform traffic signalling protocal.
Why red?
Is there any reason to
think a red stop sign
would work better than any other color
at getting drivers to stop zooming
straight through intersections
at 88 miles per hour?
One fairly obvious answer is that red
is not as likely to blend
in with the landscape
as some other colors,
which explains why the
Highway Administration
has repeatedly rejected my proposal
for a greeen and brown
camouflage patterned stop sign.
Another important point is
that, like the MUTCD says,
red is a color we consistently use
to identify warnings and peril.
Think about the Wrong Way sign
and the Do Not Enter sign.
Having consistent color
coding helps drivers learn
to identify specific colors
with specific messages.
So even if you only catch
the hint of a red sign
out of the corner of your eye,
you are more likely to react with caution,
the way you've been taught.
There are also some
behavioral research findings
that might point to the
inherent power of the color red
to command our obedience.
For example, a 2011 study
published in Psychological Science
found that male rhesus macaque
monkeys under test conditions
were less likely to try
to steal apple slices
from human experimenters dressed in red.
Now, it's important not to read too much
into these results.
The study was done on monkeys,
who could be reacting to red
for all kinds of reasons.
But it at least suggests the possibility
that there is a primate instinct
to associate red with
dominance or authority.
And if humans share this primate instinct,
the difference between a red stop sign
and a yellow stop sign
might be the difference between
"Stop in the name of the law!"
and "Hey, hey, hey guys, it might be nice
if you came to a halt, or, you know,
at least turned off your nitro boosters."
