The Irrelevant Consumer 99
friend echoed my concern, commenting that he only had a tiny
tube supplied in a wash kit from an airline to last him the five days
of our journey from the UK to Portugal; he had hoped the razor
and toothpaste he’d picked up would last the trip, but now he
wasn’t sure. The following day it transpired that he hadn’t got any
toothpaste at all. Primed by a notion of what other airlines
included in the travel kit and, presumably, the nature of the tube,
he had brushed his teeth as planned. He thought it wasn’t partic-
ularly minty or tasty toothpaste, but put that down to the airline’s
poor choice of supplier. In the morning, his mouth soured by a
particularly unpleasant taste, he checked the tube again, only to dis-
cover that it contained shaving cream.
It seems that it is impossible to prevent this priming effect.
When Kahneman and Tversky did their ground-breaking work on
behavioral decision theory, they put numbers around numerical
answers, for example from a wheel numbered from 1 to 100 that
appeared to spin at random (in fact they were controlling the out-
come), and observed that people’s subsequent responses to ques-
tions with a numerical answer were influenced by the number to
which the wheel had spun.
13
When Timothy Wilson asked people
to guess the number of physicians in a phonebook, he offered a
substantial prize, warned one subset of the participants that people
could be influenced by numbers they’d seen in earlier questions
when making estimates, and urged them to be as accurate as pos-
sible. Even under such conditions, when people might be expected
to draw on all their rational resources, the estimates provided were
influenced by irrelevant numbers placed in the preceding
questions.
14
How big a difference can priming make in surveys? David W.
Moore, author of The Opinion Makers and a former senior editor at
the Gallup polling organization, compared two polls looking at US
citizens’ support for oil drilling in Alaska’s wildlife refuge. One
found that the public was opposed to drilling there by a margin of
17 percentage points. The other, conducted within a month of the
first, found people in favor of drilling there by exactly the same
margin. (Both polls corresponded with the interests of the groups
that had commissioned them.) The poll that found more people in