MEMORIAL RESOLUTION SenD#4782
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AMOS TVERSKY
(1937-1996)
Amos Tversky, Davis Brack Professor of Behavioral Sciences and one of the
world's most respected and influential psychologists died June 2, 1996, of
metastatic melanoma, at the age of 59. Amos' contributions to the social
sciences, and to Stanford, were monumental and will continue to make their
influence felt for years to come.
His most important papers, many of which were written with his longtime friend
and collaborator, Daniel Kahneman, were unique in their depth and in the
breadth of their impact. Through a combination of carefully wrought
experiments, elegant formalizations, and an uncanny ability to draw upon
everyday experience, they offered compelling accounts of processes and
shortcomings that characterize human judgment and decision making. Amos' work
already has exerted a major impact not only on virtually every subdiscipline
of psychology, but also in statistics, law, medicine, business, and other
fields in which decision makers must weigh costs and benefits in the face of
uncertainty. The decision of litigants pondering whether to settle or go to
court, engineers weighing safety measures, and young couples considering
whether to invest in a trip to Paris or the down payment on a car can be
understood (and often could have been made wiser) through his theorizing and
research.
It is the science of economics, however, in which Tversky's and Kahneman's
ultimate influence is likely to be most lasting and profound. Most economic
analysis presupposes the rationality of actors' decisions and of the judgments
and predictions upon which those decisions are based. Tversky and Kahneman
challenged such presumptions. They demonstrated that very small risks are
given disproportionate weight, that prospective losses and gains are not
treated symmetrically, that the presence or absence of non-selected
alternatives can reverse preference orderings, and that the manner in which
options are semantically or mathematically "framed" can exert undue influence
on decision makers. These violations of normative standards, in turn, are apt
to distort private decisions and public policy alike.
Although his best known work was contained in his papers on the heuristics of
judgment and on sources of suboptimal decision making, Amos also made major
contributions to many other areas of psychology, from the foundations of
measurement to the nature of similarity assessment and the misperception of
randomness or chance. As always, counterintuitive experimental results were
his hallmark. In one notable paper, he illustrated that people judge
similarity asymmetrically; for example, they regard Tel Aviv to be more like
New York than vice versa (a powerful demonstration of the inadequacies of
Euclidean metric models of stimulus presentation). In another instantly
famous paper he confounded basketball experts by showing that the so-called
"hot-hand" was an illusion, that successive "hits" and "misses" by NBA players
did not cluster together more than expected by the dictates of chance. In yet
another memorable study with Kahneman, he showed that Stanford undergraduates,
guided by their reliance upon assessments of similarity or
"representativeness" judged the likelihood that an outspoken young liberal
named "Linda" (described to them in a brief paragraph) was a "feminist bank
teller" to be greater than the likelihood simply that she was a bank teller,
thereby violating a basic tenet of formal logic. Focusing again and again on
the gap between actual human intellectual performance and the normative
standards that should seemingly govern such performance, Amos produced at
least a dozen papers that, even by his own stringent standards, can
justifiably be termed classics.
Amos' contributions to the Stanford community were similarly memorable. A
member of the faculty senate from 1991 on, and a key advisory board member,
his counsel was sought and valued by administrators, colleagues, and students
alike. Amos' intellectual courage, especially his willingness to challenge
slipshod reasoning or politically fashionable cant were legendary. But his
integrity, fairness, openness to the ideas of others, and unfailing good humor
were equally notable. The combination of respect and affection that Amos
enjoyed so universally was captured by President Gerhard Casper who
characterized him as coming "as close to the ideal of a university faculty
member as any colleague I have known in my almost four decades in higher
education."
Amos Tversky was born in Haifa, Israel, on March 16, 1937 to parents who
emigrated from Poland to Russia. His father, Yosef, put his medical training
to use as a veterinarian and his mother Genia, served in the Knesset from its
establishment in 1948 until her death in 1964. As a young man, Amos became an
officer in an elite paratrooper unit, eventually fought in three wars, and
rose to the rank of captain. An authentic war hero, Amos' greatest fame came
for rescuing a non-commissioned officer during maneuvers. As Danny Kahneman
described the 1956 incident, the soldier "froze" after placing a charge to
blow a hole in a barbed wire fence, literally lying on top of the explosive.
Amos, then a 19 year old lieutenant, but destined to become a world authority
on risk assessment and decision making, knew the explosion would occur within
a few seconds. Nevertheless, he ran to the soldier, picked him up and threw
him to safety, only to be wounded himself. For this display of valor, he
earned Israel's highest military decoration.
Amos earned a bachelor's degree from Hebrew University in 1961, and his
doctorate in 1965 from the University of Michigan. While there, he met and
married Barbara Gans, a fellow graduate student in cognitive psychology, who
is now a professor in the Stanford Psychology Department. After holding
teaching positions at Michigan and Harvard, Amos returned to Hebrew
University, where he began his long collaboration with Danny Kahneman. He
remained at Hebrew University until joining the Stanford Faculty in 1978. In
his 17 years at Stanford, he showed himself to be a brilliant lecturer,
mentored a series of superb graduate students and post-doctoral fellows, and
set an enviable but unreachable intellectual standard for his colleagues. He
also contributed to a number of interdisciplinary programs, and was a
cofounder of the Stanford Center of Conflict and Negotiation.
Amos' accomplishments were recognized with all the honors that academia can
bestow. A fellow at the Center for Advanced Study in 1970, he was elected to
the American Academy of Arts and Sciences in 1980, and the National Academy of
Science in 1985. He also won (with Kahneman) the American Psychological
Association's award for distinguished scientific contribution in 1982, and
MacArthur and Guggenheim Fellowships in 1984, and was awarded honorary
doctorates by the University of Chicago, Yale University, The University of
Goteborg in Sweden and the State University of New York at Buffalo.
Throughout his career, Amos' intellectual and emotional connections to Israel
remained strong. He was affiliated with Tel Aviv University and maintained
close ties with Hebrew University as well, returning each year to deliver
lectures and continue his collaboration with numerous colleagues and students.
Fittingly, well-attended memorial symposia were held in 1997, both at Stanford
and in Israel. At each, students and colleagues from psychology and a range
of other disciplines lauded Amos' intellectual contributions; but they also
spoke with great affection, and profound sense of loss, about his warmth, his
humanity, and his joie de vivre. As more than one of his collaborators noted
there simply was no one more fun to talk with, to, work with, or simply be
with. He truly radiated a "special light."
In the last months of Amos' life he continued, with characteristic courage and
remarkable good cheer, to live the life he valued most. He completed papers
and a final edited volume with Danny Kahneman, fulfilled his responsibilities
to the advisory board with undiminished commitment, watched NBA basketball,
read about physics and physicists (a lifelong avocation), and enjoyed poetry,
prose, and music in Hebrew, the language he so loved. He also spent
increasingly amounts of time with Barbara and his children, Oren, Tal, and
Dona, telling wonderful stories, and distilling the wisdom of his remarkable
lifetime of experience. As his strength diminished, and the impact of his
illness could no longer be concealed or ignored, he increasingly was obliged
to give comfort not only to his family, but to shocked friends and colleagues
as well. With characteristic wisdom, and grace, he helped us "frame" his 59
years not as a tragically shortened life, but as a wonderfully fulfilling and
complete life‹albeit one that happened to be too short. He reminded us, as he
always did, of the privilege he felt in being associated with university life.
Amos died at home peacefully, in the embrace of his family, his personal and
intellectual legacy secure. His life defined what it meant to be a great
psychologist and colleague. It also defined what it means to be a mensch.
Committee:
Kenneth Arrow, Chair
Gordon Bower, Psychology
Brad Efron, Statistics
Eleanor Maccoby, Psychology
Lee Ross, Psychology