Retrospective: In Memory of John Maynard Smith (1920-2004)
When John Maynard Smith died on 19 April at the age of 84, one of the last
grand evolutionary theorists of the 20th century passed. The example of
Charles Darwin has induced intellectually ambitious biologists, many of
them in Britain, to search for general formulations by which evolution as a
whole, or large domains of evolutionary phenomena, can be understood and
explained. One thinks of R. A. Fisher's self-consciously named "Fundamental
Theorem of Natural Selection" (which turned out not to be quite so
fundamental or general as Fisher thought), or W. D. Hamilton's theory of
kin selection, the chief theoretical tool used to explain the origin of
cooperative, social, and apparently altruistic behavior in a world
supposedly dominated by the struggle for existence.
Maynard Smith saw that a major remaining problem in evolutionary theory was
to explain the evolution of characteristics whose reproductive advantage or
disadvantage to an individual depended on the response of other
individuals. So, for example, is it reproductively advantageous for an
animal to engage in threatening aggressive behavior toward another animal
when they are competing for a bit of food or space? If the response of the
second animal is to back down, then the aggressive behavior has paid off,
but if the opponent meets aggression with aggression, then an escalating
conflict may leave both of them dead. Maynard Smith realized that this
class of evolutionary problem could be approached through game theory. His
invention of the concept of an Evolutionary Stable Strategy created a new
and lively branch of theoretical studies of evolution.
Although the concept of the evolutionary game has considerably enriched the
way in which evolutionists think about the history of life, what remains
unclear is the extent to which it will be possible to measure in nature the
quantities that are required to turn the theory into a predictive device.
It is very difficult to measure fitnesses in nature and especially the
kinds of contingent fitnesses of genotypes that depend on what other
interacting individuals are doing. Moreover, Evolutionary Stable Strategies
only tell us whether, if a particular strategy is adopted by the entire
population, an alternative strategy can invade at low frequency. They tell
us nothing about the stability of the strategy after massive invasion by
alternatives, as might occur from mixtures of populations with different
strategies. It may turn out that game theory will serve only as a rough
heuristic rather than as a precise mode of evolutionary prediction.
The impact of evolutionary game theory has been such that Maynard Smith's
earlier, largely experimental work has been unduly neglected. His
demonstration that there is a trade-off between female fertility and
longevity in Drosophila is of general importance to our understanding of
the evolution of life histories. His marvelous experiments with K. C.
Sondhi on changing invariant characteristics by selection is one of the
best demonstrations of Waddington's claim that there is considerable hidden
genetic variation underlying such constant features, variation that can be
made manifest when development is disrupted. Most extraordinary was their
ability to produce heritable asymmetry in a normally bilaterally
symmetrical organism such as Drosophila. Such experiments are as important
to our understanding of evolutionary processes as Maynard Smith's more
seductive work on game theory.
John Maynard Smith was the child of a Harley Street surgeon, spent much of
his youth on Dartmoor, attended Eton College, and went on to Trinity
College, Cambridge. Like so many of his upper-middle class contemporaries
at Cambridge in the 1930s, he became enamored of Marxism and joined the
Communist Party. He told me he was recruited into the party by Harry Harris
(who later achieved fame as a human biochemical geneticist), and that Harry
was the first urban Jew he, a boy from Dartmoor, had ever laid eyes on.
Like so many others he became disillusioned by Stalinism and left the
Communist Party after the Hungarian uprising. This was a common pattern. I
once sat in the Staff Club at the University of Sussex with Maynard Smith
and a number of other faculty members trying to recall whether a particular
person had been a member of the Communist Party. John said he couldn't
remember and asked the man on his right, who couldn't remember either but
asked the man on his right, and so on around the whole circle. Unlike so
many Americans of a similar history, neither Maynard Smith nor his
colleagues became hardened rightists, but held on to their socialist
sympathies, so much so that when I told a British immigration officer that
I was to spend a year at Sussex he remarked, "Ah, that Bolshie University!"
John Maynard Smith was a humane, humorous, and sensible person who did not
take himself or other people more seriously than they deserved. He had a
sensibly skeptical view of science and its claims, which is best
encapsulated in the famous dictum of his teacher, J. B. S. Haldane, who
said that a scientific idea ought to be interesting even if it is not true.
*The author is at the Museum of Comparative Zoology, Harvard University,
Cambridge, MA 02138, USA. 10.1126/science.1099576
Volume 304, Number 5673, Issue of 14 May 2004, p. 979.
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