74 Scientific American, September 2019 Illustration by Wesley Allsbrook
TOUGH
CALLS
HOW WE MAKE DECISIONS IN THE FACE OF
INCOMPLETE KNOWLEDGE AND UNCERTAINTYBy Baruch Fischho
Psychologists study how humans make decisions by giving people “toy” prob-
lems. In one study, for example, my colleagues and I described to subjects a
hypothetical disease with two strains. Then we asked, “Which would you rather
have? A vaccine that completely protects you against one strain or a vaccine that
gives you 50 percent protection against both strains?” Most people chose the
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protection, even though both shots gave the same overall chance of getting sick.But we live in a world with real problems, not just
toy ones—situations that sometimes require people to
make life-and-death decisions in the face of incom-
plete or uncertain knowledge. Years ago, after I had
begun to investigate decision-making with my col-
leagues Paul Slovic and the late Sarah Lichtenstein,
both at the firm Decision Research in Eugene, Ore.,we started getting calls about non-toy issues—calls
from leaders in industries that produced nuclear
power or genetically modified organisms (GMOs).
The gist was: “We’ve got a wonderful technology, but
people don’t like it. Even worse, they don’t like us.
Some even think that we’re evil. You’re psychologists.
Do something.”Psychologist Baruch
å`¹is Howard
Heinz University Pro-
fessor in the depart-
ment of engineering
and public policy and
the Institute for Poli -
tics and Strategy at
Carnegie Mellon Uni-
versity. He is a member
of the National Acade-
my of Sciences and
National Academy
of Medicine and past
president of the Soci-
ety for Risk Analysis.
DECISION SCIENCE