992 THE STRUCTURE OF EVOLUTIONARY THEORY
happy story of Heather Winklemann, a senior who had just won a prestigious
Marshall Fellowship for graduate study in England. The article focuses on her
intimidating but successful oral interview, held in San Francisco. As a prospective
paleontologist, the committee asked her: "Does evolution work by punctuated
equilibrium? Answer yes or no?" Ms. Winklemann replied cogently by exposing the
dichotomy as false—and she got her fellowship. The article ends: "'That question
took me by surprise,' Winklemann recalls, 'because if you know anything about the
topic you know it can't be answered with a yes or a no. Were they trying to catch me
on the question? I told the committee that I couldn't give a yes-or-no answer and
why.' Heather Winklemann's answer evidently was what the committee was hoping to
hear."
Beyond dichotomy, a failure to recognize the theory's proper scale stands as the
most common journalistic error about punctuated equilibrium, in accounts both
positive and negative. Many reporters continue to regard yearly or generational
changes in populations as a crucial test for punctuated equilibrium. Thus, Keith
Hindley reported the fascinating work of Peter Grant and colleagues on changes in
population means for species of Darwin's Galapagos finches following widespread
mortality due to extreme climatic stresses. Hindley placed the entire story in the
irrelevant light of punctuated equilibrium (which cannot even "see" such transient
fluctuations in population means from year to year): "Striking new evidence has
refuelled the heated scientific debate about the process of evolution... The followers
of Stephen Gould of Harvard claim that such rapid changes or 'jumps,' caused by
environmental pressures, are the key to the emergence of new species... This episode
has provided Gould's supporters with some of the ammunition their theory has so far
lacked: good examples of sudden evolution among species alive today."
Negative accounts of punctuated equilibrium often make the same error. In
reviewing a book by Ernst Mayr in the New York Times, Princeton biologist J. L.
Gould (no relation) discusses the link of punctuated equilibrium to Mayr's views on
allopatric speciation. But he then attacks punctuated equilibrium because "its authors
seem to believe that species-level changes can occur in one generation, presumably
by the production of what the embryologist Richard Goldschmidt called 'hopeful
monsters.'"
Among human foibles, our tendency to excoriate a bad job in public, but merely
to smile in private at good work, imposes a marked asymmetry upon the overt
reporting of relative frequencies in human conduct and intellect. In truth, although I
have singled out some "howlers" for quotation in this section, most press reports of
punctuated equilibrium have been accurate, while a few have been outstanding.
Consequently, I close this section on punctuated equilibrium and the press with two
extensive quotations from two leading science writers, one British and one
American—with thanks for confirming my faith in the coherence and accessibility of
the ideas and implications of punctuated equilibrium. In The Listener (magazine of
the BBC) for July 19, 1986, Colin Tudge beautifully explains the key concepts and
general reforms proposed by punctuated equilibrium, while also giving the critics
their due: