Chapter 18

Distributed Cognition

Donald A. Norman

Modern commercial airplanes fly with two or three people in the cockpit. One,
who sits in the front left-hand seat, is the captain, the person in charge. Asec-
ond pilot, the first officer, sits in the front right-hand seat. In older aircraft, a
third person, the second officer or flight engineer, sits sideways just behind the
first officer, facing a panel of controls and displays on the wall of the cockpit.
The captain and first officer usually alternate jobs, one flying the airplane dur-
ing one leg of the trip, the other flying during the next leg, so they also desig-
nate themselves by the labels ‘‘pilot flying’’ and ‘‘pilot not flying.’’
The two pilots sit in front of a large panel, the captain’s side largely dupli-
cating the first officer’s side, with a large control wheel—something like the
steering wheel of a car—in front of each pilot. The two wheels are linked, so
that whenever one pilot turns one wheel or moves it forward or back, the other
wheel follows along. In between the pilots is another set of instruments for
controlling the engines, radios, and flaps. These instruments and controls are
used by both pilots, so there is only one set (see figure 18.1).
Control rooms—whether the cockpit of a commercial airliner or an industrial
plant—tend to contain great big controls. In power plants, there are huge elec-
trical switches, huge meters that display the state of the plant. Because there
may be thousands of controls and displays—in one nuclear power plant that I
studied, there were an estimated four thousand controls and displays—the
rooms are huge, as large as a small house. Several people will normally be
monitoring the controls, depending upon the plant and the activity taking
place. Large controls in spacious control rooms are the norm in industry. I have
seen similar displays and controls in large ships, chemical processing plants,
manufacturing plants, and even the control room for one of the lines of the
Paris Metro.
The first thought that strikes the modern scientist looking at the controls is
that they seem quaint and old-fashioned. When I first saw a nuclear power
control room, I was also struck by the thought: ‘‘Why on earth does it have to
be so big?’’ Sure, once upon a time, you probably needed a big wheel to turn
the rudder of a ship or to operate the control surfaces of an airplane. Once you
needed big electrical switches to control all the current that passed through
them. You needed big meters and indicators so that they could be seen as the
operators walked up and down in the control room. But today none of this
is necessary. Most modern equipment is controlled remotely. It is no longer

From chapter 6 inThings That Make Us Smart(Reading, MA: Addison-Wesley, 1993), 139–153.
Reprinted with permission.