ARE OUR brains like Swiss army knives, full of built-in devices for
understanding maths and detecting cheats? Do men commit rape to pass on their
genes? And do we enjoy gardening as an evolutionary throwback to our savannah
past? These are some of the claims that have filled the pages of fashionable
books alleging that there is a new “Darwinian” science out there, called
evolutionary psychology (EP). “Evolutionary” has become a term that can be
applied to everything from economics, medicine and sociology to ethics and art
criticism.
EP’s central argument is that present-day human behaviour has its roots in
how our ancestors thought, acted and felt in our Pleistocene past. This
behaviour, so the thinking goes, has been fixed by natural selection, regardless
of whether or not it is relevant or useful to 21st-century people. But how can
we tell how our ancestors behaved in the Stone Age? According to EP, by a
process of “reverse engineering”. That is, you look at people today and guess
how we may have got there through evolution.
With this sort of ungrounded speculation, EP swaggers across the sciences,
from evolutionary theory itself to neuroscience, anthropology, sociology and
philosophy. Its protagonists insist that with 20:20 prehistorical hindsight, and
the application of what they call “Darwinian method”, they can offer better
explanations of phenomena ranging from child abuse to morning sickness than can
criminology or physiology. Sound bites of this sort make good headlines, but can
they stand up to rigorous scrutiny?
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Darwin mistrusted speculation. His own theoretical conclusions were based on
extensive, meticulous observation and careful experimentation. EP’s evolutionary
assertions ignore both. Let’s begin with the idea that we know what our
ancestors were doing in the Stone Age. You don’t have to have a Nobel prize in
palaeontology to know that we can’t. When there is still a debate over the sex
of Lucy, the hominid whose fossilised remains were dug up in Ethiopia, fantasy
constructions of Stone Age family relations sound more like episodes from
The Flintstones than examples from a new discipline seeking to be taken
seriously. Geoffrey Miller’s recent book The Mating Mind goes as far as
to include a section speculating on how a Stone Age teenager might have related
to her mother’s live-in lover.
Then there’s EP’s claim that the roots of human behaviour haven’t changed
since the Pleistocene, between 10 000 and 1.6 million years ago. You’d have
thought that this would be long enough for us to adapt to new circumstances. But
EP’s supporters say it isn’t. This is a strange assertion given that
evolutionary biologists have found that, over successive generations, the leg
length of English sparrows transported to the US increased by 5 per cent in a
century in response to new environmental challenges. And that patient decades of
study of the Galapagos finches by Rosemary and Peter Grant have shown how the
birds’ beak shapes can alter significantly over a couple of generations in
response to periods of drought or abundance. Surely there ought to have been
plenty of time in the human generations that have elapsed since the Stone Age
for humans to adapt in response to changes in social, cultural and technological
conditions—to say nothing of climate change.
What’s more, in the 150 years since Darwin, evolutionary theory has moved on.
Palaeontologists and molecular geneticists (for instance, Mooto Kimura, Stephen
Jay Gould, Niles Eldredge and Gabriel Dover) have added such themes as neutral
mutation, punctuated equilibrium, exaptation and adoptation, making it clear
that there’s no simple formula linking changes in an organism’s genes to changes
in its physiology. Ignoring such important developments is no way to advance
science. As Darwin sighed in the last edition of On the Origin of
Species, confronting those who claimed that he regarded natural selection
as the only means of evolutionary change: “Great is the power of steady
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Riding roughshod
This insistence on simple-minded evolutionary guesswork enables evolutionary
psychologists to ride roughshod over many areas of science. The intricate
processes of brain development explored by neurophysiologists and developmental
biologists get short shrift from evolutionary psychologists. Steven Pinker, for
example, sees neurobiology as irrelevant to his invocation of a universal human
“cognitive architecture” based on innate modules apparently generated in the
Pleistocene. This description of the mind as an information processing device
may suit computer buffs. But for those of us whose minds and brains deal not so
much with information as with meaning, and less with emotion than with
cognition, Pinker’s picture is profoundly unsatisfactory. Unsurprisingly,
Pinker’s speculative theorising enrages neurobiologists.
But what is perhaps most damaging about EP is its systematic devaluing of
serious research in disciplines outside the natural sciences. For example,
Canadian psychologists Margo Wilson and Martin Daly theorise, on the basis of
their belief that parental love is genetic, that there is an evolutionary
propensity for men to abuse or murder their stepchildren. While it is true that
the rates of such crimes are higher in families with a nonbiological father,
these are still a minority of stepfathers. It is a poor theory which can’t
explain why most stepfathers do not commit such crimes
(91av, 13 May, p 9).
Social research instead points to second families being under tremendous
pressure both emotionally—not least because the biological father is still
in the frame—and financially. Such proximal explanations, as the
philosophers of science would name such contextual accounts, are better grounded
than untestable evolutionary speculations.
Perhaps the worst example of such ill-informed assertions comes from
Randy Thornhill and Craig T. Palmer in their recent book, A Natural History
of Rape. They claim that rape is an evolutionary strategy adopted by
otherwise sexually unsuccessful men to pass on their genes. Thus their
definition of rape is restricted to the forced penile penetration of fertile
women. So victims of forced anal or oral sex or same-sex rape, as well as raped
pre-pubescent girls or post-menopausal women, have, according to the authors,
not been raped at all. To support their cause they turn to Thornhill’s
observations of male scorpion flies, which under well-defined circumstances will
all proceed to forced sex.
But even though there is plenty of evidence pointing to the social contexts
when the incidence of rape increases, there are no well-defined circumstances
when all men will rape. Men are just a shade more complicated than
scorpion flies, not least because of the evolution of the human brain, to say
nothing of the values which bind societies together. Yet Thornhill’s claims were
talked about and written about in the serious media as serious science. This EP
theory of rape is not only poor science. It is also socially irresponsible, as
its pernicious influence could set back the struggle being waged in the courts
against this violent sexual crime.
Faced with trying to explain why their theories don’t actually fit the data,
the proponents of EP fall back on a free-floating and unbiologically based “free
will”. “Only we have the power to rebel against the tyranny of our selfish
replicators,” proclaims Richard Dawkins. “If my genes don’t like what I do they
can go jump in the lake,” insists Steven Pinker. What gives us such power to
tell our genes what they can or cannot do? Darwin, rejecting the notion of free
will, knew far better. The exploration of human agency and subjectivity by the
social sciences has rather more going for it than this reaching for a sky-hook
to escape a problem of EP’s own making.
Human behaviour is complex and demands complex explanations. Yet EP is
trapped within an almost religious longing for simple-minded explanations. Given
a choice between a complex explanation, for instance of why women who are
generally poorer should prefer richer men as fathers for their children, and
some Just So Story about life in the Stone Age, they prefer the latter. They
simply disregard evidence to the contrary, which shows, for instance, that as
women become more financially secure they no longer opt for older rich men.
The contributors to our forthcoming book, Alas, Poor Darwin, are
drawn from many disciplines, ranging from philosophy, sociology and cultural
criticism to animal behaviour, neuroscience and molecular biology. They argue
that such grandiose speculations, based on weak or non-existent evidence, both
steadily misrepresent Darwin and ignore or dismiss findings and theorising from
contemporary research.
But attacking a poor argument is no substitute for replacing it with a
better. In consequence, Alas, Poor Darwin accepts the interdisciplinary
challenge of EP, but recognises the complexity of the world we live in, and the
necessary autonomy of the many disciplines trying to understand and explain it.
Lastly, the very interdisciplinarity of the book serves to demonstrate that
despite the sterility of the “science wars” between social and natural
scientists, it is entirely possible for people from radically different
disciplines to enjoy listening to and learning from one another.
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Alas, Poor Darwin: Arguments against Evolutionary Psychology, is published
by Jonathan Cape on 6 July. Contributors include Patrick Bateson, Gabriel Dover,
Stephen Jay Gould, Mary Midgley and Dorothy Nelkin