Are Human Beings Alike Or Different? The Evidence Is In, But It`s Hard To Talk About
The human sciences are in a paradoxical situation.
Vast quantities of
new data are pouring in, particularly from the
exponential improvements in genome sequencing. Yet
theorizing about what the new data imply has seldom been
more career-threatening—as the fates of
James Watson and
Larry Summers show.
Perhaps not surprisingly, the May 10, scientific
conference on "Evolution, Culture, and Human
Behavior" at UC Irvine, which brought together
leading theorists for a day of presentations centered
around the debate over human uniformity vs. human
biodiversity, flew under the radar. It needed only a
single normal-sized classroom.
Still, the few dozen spectators included an honor
roll of prominent figures in the human sciences.
Leda Cosmides, the co-developer of the field of
evolutionary psychology. Also: John Hawks, the
young anthropologist from the University of Wisconsin,
whose remarkably broad range of expertise, from the
oldest bones to the latest statistical techniques for
genetic analysis, has quickly made him a
star science blogger.
Hawks is already a strong prose stylist. If he
continues to improve, he could someday fill the job of
the human sciences` Public Sage—a role for which such
Stephen Jay Gould,
Edward O. Wilson,
Richard Dawkins, and
Steven Pinker have competed.
And in attendance: Gregory Cochran. In evolutionary
theory over the last decade, Cochran has been
the straw that stirs the drink—as slugger Reggie
described his function on the tumultuous 1970s
Yankees baseball team. (Here`s the unofficial
Cochran Fan Site.)
There were four main speakers:
Shinobu Kitayama, director of the Culture and
Cognition Program at the University of Michigan.
Kitayama discussed the sizable differences in
Americans and Japanese. Just as the stereotype would
suggest, Americans are
more independent; the
Japanese more interdependent. Americans like to feel
individually in control of the situation; the Japanese
are happiest when their group is cohesive.
Interestingly, the Japanese on the northernmost
island of Hokkaido generally fall midway between the
Japanese and American norms. Kitayama speculates that
this is related to Hokkaido having been a wilderness
frontier, not settled until the late 19th Century,
rather like the United States.
Thomas J. Bouchard, the principle organizer of
the famous "Minnesota
Twins" study that reunited separated twins.
Bouchard explained that the state of the art in twin
and adoption studies shows that IQ is highly heritable.
Remarkably, the heritability of IQ goes up as we age.
Identical twins who grew up together tend to become more
alike in IQ when they are adults living apart than when
they were children in the same home.
The conference was organized and emceed by UCI
Chuansheng Chen and
Robert Moyzis, one of the co-authors of the
late 2005 paper "Global
landscape of recent inferred Darwinian selection for
Homo sapiens" [PDF], which listed
1,800 genes that have been under varying selection
East Asia over the last 50,000 or so years. This
shattered the conventional wisdom that Darwinian
selection had somehow ceased to operate on the human
species when our ancestors first left Africa. The
data now suggests what common sense always
implied—that when humans dispersed out of the
tropics, the new environments they encountered, such
as cold weather, led to important degrees of racial
The central argument of the conference turned out to
be between the other two speakers, the prominent
Henry Harpending of the
University of Utah and
John Tooby of
UC Santa Barbara over, in effect, whether diversity
or uniformity best characterizes humanity.
Harpending spoke first on the accumulating evidence
that human evolution has actually accelerated since we
came out of Africa, especially after the invention of
agriculture. This was proposed by Harpending, with
Cochran, Moyzis, Hawks, and Eric T. Wang, in their
important December 2007 paper "Recent
acceleration of human adaptive evolution", [PDF]
which appeared in the Proceedings of the
National Academy of Sciences
For example, Harpending suggested that the
prehistoric spread of
Indo-European languages across a huge swath of
Eurasia from India to Ireland might have been made
possible by a beneficial
genetic mutation for "lactose
tolerance." This allows many adults in this
drink milk without gastro-intestinal discomfort. In
the right terrain for dairying, a tribe whose adults can
get much of their nourishment from the milk of cattle or
goats has a big competitive advantage over tribes that
can`t—perhaps allowing the Proto-Indo-European-speaking
milk drinkers to impose their language and spread their
By the way, a "lactose tolerance-centric"
theory of world history was put forward by the
Irish dairy farmer-turned-economist Raymond D.
Crotty in his ambitious but little known 2001 book When Histories Collide: The Development and Impact of Individualistic Capitalism.
(It hasn`t been published in the U.S., but
part of it on
Google Books. And here is a
brief summary.) Crotty attributed the medieval rise
property rights and the rule of law in Northwestern
Europe to deep roots going back to the type of European
agricultural society made possible by the evolution of
In contrast, John Tooby, co-founder of evolutionary
psychology with Leda Cosmides, who is his wife,
countered Harpending`s emphasis on human biodiversity
Gray`s Anatomy Test.
Open that 1918
book of medical charts at random, close your eyes,
and poke a drawing. In all likelihood, whatever tiny
anatomical detail you`re touching can be found in
virtually everybody on Earth. (Or at least everybody of
Although the parts differ in size from person to
person, the basic human blueprint is extremely uniform
in terms of which parts are used.
This uniformity is what allows sexual reproduction.
Imagine that you want to assemble a working Toyota Camry
from the parts of two other cars, Tooby suggests. You`ll
see that you`d better start with two other Toyota
As cognitive scientist
Steven Pinker wrote in his 1994 bestseller The Language Instinct,
produced after a sabbatical year spent in
Santa Barbara with Tooby and Cosmides, "To a
scientist interested in how complex biological systems
work, differences between individuals are so boring!"
Well, that`s one way of looking at it …
Tooby also suggested that human nature is reasonably
uniform in many behavioral areas as well. For instance,
in virtually every society currently in existence,
incest within the nuclear family is unusual and socially
Sigmund Freud famously theorized that humans
desperately want to commit incest with their nearest and
dearest relatives, and that makes necessary the
convoluted apparatus of
Freudianism. But Finnish anthropologist
Edvard Westermarck offered a simpler idea way back
in 1891: that humans have evolved an instinct to find
incest repugnant because it leads to birth defects. (In
a 2007 paper in Nature, "The
Architecture of Human Kin Detection," [PDF]
Tooby, Cosmides, and Debra Lieberman offer what they
believe are the two rules for recognizing
siblings—seeing your sibling being nursed by your
mother, or being raised together–that make
Westermarck`s instinct feasible.)
So who is right? Is the human race uniform or
Well, they`re both right. It all depends upon what
you`re interested in at the moment.
That`s usually how it goes—the things that
interest us the most, that get us most worked up,
are those that are on the knife edge, that look
different when viewed from different angles.
Let`s consider a similar question that`s remote
enough that we can think about without political biases
getting in the way: Is the universe empty or full?
And yet, outer space is also famously full of "billions
and billions" of stars, as Johnny Carson used to
say when parodying astronomer Carl Sagan. In 2003, a
team of Australian astronomers estimated that there are
70 sextillion stars in the known universe. That`s
Now, it`s perfectly reasonable to conceive of the
universe both ways, depending upon what you need to
think about at the time. The incredible emptiness of
space is terribly important to understand if you are,
say, contemplating an interstellar voyage. Nevertheless,
to be frank, once you grasp that fact, it gets kind of
boring to think about. So,
astronomers spend more time thinking about the tiny
fraction of space that isn`t empty, those 70 sextillion
Well, that`s not a very big number.
But Wikipedia goes on to say, "However, with a
genome of approximate 3 billion nucleotides, on average
two humans differ at approximately 3 million nucleotides."
Well, three million is a pretty big number. (It`s not
as big as 70 sextillion, but still …)
Of course, probably they would not at all be very
different at all compared to space aliens possibly
living on a planet going around one of those 70
And if those aliens showed up in hostile
flying saucers to
conquer the human race, no doubt Shaq and Shakira
and everybody else would team up to fight them off.
Ronald Reagan said exactly this to the United
Nations back in 1987:
"I occasionally think how
quickly our differences worldwide would vanish if we
were facing an alien threat from outside this world."[Address
to the 42d Session of the United Nations General
Assembly in New York, New York]
But, we`re not facing space aliens. So the
differences between humans are interesting—and
When it comes to thinking about race,—which is all
about who your relatives are—it`s all, well,
features his daily blog.]