Today, we try to get rid of the instruction manual.
The University of Houston's College of Engineering
presents this series about the machines that make
our civilization run, and the people whose
ingenuity created them.
My favorite cafe has a door
handle in the shape of a flat plate. The sign above
it says PULL. Visit after visit I push the door
instead of pulling on it. I thought I might be
brain-damaged. Now I've read Donald Norman's book,
Turn Signals Are the Facial Expressions of
Automobiles, and I am vindicated.
That flat plate is a clear invitation to push. The
question is, are you tuned to visual cues or verbal
ones? You have to be tuned to the written word to
notice the word PULL before you react to the plate.
If you're better tuned to mechanical function, and
most of us are, you'll see that inviting plate
Next Norman goes to a scene I was in last summer.
Sydney, Australia, takes great pride in its
downtown monorail system. When I tried to use that
system, it gave me fits.
It's all well labeled. Yet they need an attendant
to help people like me through the gate. Norman
looks at that system for visual cues. You look for
a place to put your token. But the first slot you
see on the gate is the one where your ticket comes
out. "We've tried all sorts of signs," the
attendant complains. "People just can't seem to
It gets worse: The command on the left side of the
token dispenser tells you to push a button on the
right. The command on the right tells you to put a
coin in the slot on the left. The visual and
written cues contradict each other.
I remember rushing to my meeting, trying to get a
token in a hurry and having to go to the attendant
for help. The system is, indeed, a masterpiece of
Norman moves on. He shows us electric stoves where
the switches don't match the burners. A low
ice-cream freezer cabinet, at the end of a lunch
line, has sliding doors on top. You obviously lay
your tray on one side while you open the other.
Trouble is, the glass doors aren't meant to support
any load. The top is cracked, of course. Too late,
they've pasted a sign on it: "Please do not put
your tray here."
So I add my own examples. A friend hands me a key
and asks me to lock his car door. "I already did."
"But I have the key," he says. By pure accident I'd
read the manual for a similar car. I knew how to
lock it without the key by moving the handle. But
who reads manuals? Normally I don't. After 50,000
miles of use, he still didn't know. There was no
Instructions are such clumsy things. Machines can
so easily be self-explanatory. A good machine leads
the eye accurately. But designers can forget how
much information still flows when nothing at all is
written -- when nothing is said.
I'm John Lienhard, at the University of Houston,
where we're interested in the way inventive minds