Latest Mind and Matter column in the Wall Street Journal:
"You can't change human nature." The old cliché draws support from
the persistence of human behavior in new circumstances.
Shakespeare's plays reveal that no matter how much language,
technology and mores have changed in the past 400 years, human
nature is largely undisturbed. Macbeth's ambition, Hamlet's
indecision, Iago's jealousy, Kate's feistiness and Juliet's love
are all instantly understandable.
Recently, however, geneticists have surprised themselves by
finding evidence of recent and rapid changes in human genomes in
response to the pressures of civilization. For example, fair skin
allows more absorption of the sun's ultraviolet rays necessary for
the skin to make vitamin D. So when the northern Europeans, living
in a climate with little sunshine, started to farm wheat, a food
low in vitamin D, they evolved fair skin to compensate and get more
of the vitamin.
So human nature may also have genetically evolved a bit in 10,000
years. People of European and Asian descent in particular have
probably adapted to living more sedentary and crowded lives. But
surely not very much. Eurasians' general nature differs little from
those whose ancestors were still scattered hunter-gatherers just a
few generations ago: many Africans, Americans and Australians.
Besides, genetic changes can't explain short-term history. A
glance at world trade statistics confirms that four decades of
communist rule, designed to change human nature from
individualistic to communitarian, failed to extinguish the habits
needed for commerce from the Chinese personality.
So if there is a human nature it is likely to be mainly universal
and ancient. Ten years ago, the evolutionary psychologist Robert
Kurzban did an ingenious experiment to show what can change and
what can't. Generally, three features dominate an American's
description of another adult: age, sex and race. Dr. Kurzban found
that the tendency to categorize by race could be changed more
easily than the other two.
His subjects were asked to form an impression of individuals whom
they watched in conversation. They then saw a sequence of sentences
and had to recall who said what. Misattribution revealed a tendency
to categorize: People confused men for men and women for women, old
for old and young for young, black for black and white for
white.
But if the conversation showed a pattern of two coalitions with
different views, then misattribution by race, but not by sex or
age, ceased. "Less than four minutes of exposure to an alternate
social world was enough to deflate the tendency to categorize by
race." People seem to use race as a shorthand for "group," as if
skin color were a different uniform, but drop it if the group cuts
across races.
Dr. Kurzban argued that in the ancient hunter-gatherer past,
people almost never encountered other races, but frequently
encountered other groups. So racial categorization is not "human
nature" but culture latching on to a "groupishness" that's part of
human nature.
Confirming that finding, a more recent experiment by Katherine
Kinzler at the University of Chicago found that (as her paper's
title says) "accent trumps race in guiding children's social
preferences." Presented with photos and sometimes recordings of
other children, kids chose to be friends with those of the same
race if silent, but preferred those with accents like their own
when they heard recordings.
An unvarying human nature can still generate very different
behavior. In his new book, "The Better Angels of Our Nature,"
Steven Pinker, trying explain the steep decline in nearly all forms
of violence in recent centuries, insists that the inner demons that
once drove us to violence are still there, just expressed in less
destructive ways because of cultural changes that have given
empathy, self-control, morality and reason the upper hand.
As Dr. Kurzban puts it, "If you let a creature develop in a world
with laws that themselves have been through some interesting
selection process, then that creature will be different from one in
a world with different institutions."
