A Temperamental Journey
An Argument for Mind. Jerome Kagan. xiv + 287 pp. Yale
University Press, 2006. $27.50.
In an old New Yorker cartoon, one crotchety-looking guy in
a lab coat says to another, "One thing I'll say for us,
Meyer—we never stooped to popularizing science." The same
can't be said of Jerome Kagan, emeritus professor of psychology at
Harvard. Kagan is one of the most famous developmental psychologists
in the world, and yet I have seen the mention of his name provoke
eye rolling among some academics—probably because he is both a
popularizer, with an enthusiasm that can seem showy, and a
generalist, with research interests that range from the biological
to the cultural ends of the spectrum. Such scornful scholars may be
thinking that it is slightly unseemly to venture out of the lab into
public view or that breadth of interest necessarily sacrifices depth
Kagan's latest book, An Argument for Mind, mixes
autobiography with a history of psychology over the past 50 years.
He uses his own journey from the Ph.D. program in psychology at Yale
to the Fels Research Institute and then to Harvard to illustrate the
movement of the field from the behaviorism of the 1950s and its
overemphasis on environmental causes of behavior to the current
acknowledgment of the importance of biological influences. Kagan
contributed to this movement from nurture toward nature with his
research on temperament, or biologically based differences in infant
personality. He takes the position that some children are naturally
predisposed to be inhibited or exuberant, although these tendencies
can be altered by experience. In other words, nature and
nurture are important.
Kagan may be a victim of his own success, however, in that this
conclusion, which would have been startling in the 1950s, seems
unsurprising in 2006. Indeed, empirical evidence consistent with
Kagan's claims about the biological bases of behavioral tendencies
continues to come in, such as the recent finding by Gleb Shumyatsky
and colleagues that removing a single gene associated with protein
expression in the amygdala reduces fearful behavior in mice.
Kagan has never been one to shy away from controversy or the
limelight. He picked a very public fight with attachment theorists,
arguing that their procedures really measure a child's temperament
more than the security of the emotional bond between child and
parent. And in the late 1990s, when Judith Rich Harris burst onto
the scene with her critiques of developmental psychology (most
notably in her 1998 book The Nurture Assumption), Kagan
took it upon himself to defend the field, denouncing her conclusions
in unusually strong terms ("total nonsense,"
"crazy"). The two of them clashed in the online magazine
Slate in 1998 and on an ABC News special in 1999. In the
ABC News piece, Kagan implied that Harris, a textbook writer, is
unqualified to interpret the research literature because she is not
a researcher herself. Students to whom I have shown this video have
commented that Kagan comes across as a snob. Kagan's ire toward
Harris is somewhat surprising in that they are in many ways natural
theoretical allies: On the nature-nurture issue, they both emphasize
heredity and criticize attachment theory's emphasis on early
experience. They differ, however, in their relative weighting of
environmental influences, with Harris giving more weight to peers
and less to parents.
Kagan says in An Argument for Mind that he does not enjoy
the role of critic, but he certainly plays that part a lot. For
example, he is critical of the selfishness, hedonism and materialism
of modern Western culture. He also criticizes evolutionary biology's
assumption that human behavior is primarily driven by maximizing
reproductive success and inclusive fitness; he believes that we are
instead more motivated by the desire to be virtuous—to meet
our personal moral standards. And he also suggests that one cannot
use evolutionary theory to explain the popularity of
religion—yet both psychologist Jesse Bering and philosopher
Daniel Dennett have recently done just that.
The book takes its title from a chapter in which Kagan rejects
neuroscience's claim that understanding the mind will eventually be
reduced to understanding the brain. He argues that psychological
properties are emergent and not reducible to physical terms. His
position is not new; similar arguments have been made by
philosophers of mind such as Jerry Fodor and Thomas Nagel. However,
Kagan provides an excellent summary of the evidence for the
nonequivalence of physical and psychological states.
Kagan expounds repeatedly on his personal philosophy of science.
Researchers should prefer hypotheses and categories suggested by
open-minded observation over those derived from theoretical
preconceptions, he argues. For example, Kagan believes that many
current psychological terms, such as stress and
fear, are too broad to be useful, because they lump
together states with very different physical manifestations and
psychological impacts, especially across cultures and species. He
predicts that psychological descriptions in the future will be much
more context-specific, even considering the season of year and time
of day. He also discusses how the popularity of scientific theories
depends on how well they mesh with the zeitgeist of the culture. For
example, behaviorism's emphasis on nurture over nature resonated
with American egalitarianism ("all men are created
equal"), and Freud's psychoanalytic theory fits with American
ambivalence about sexuality. Finally, Kagan argues that society
should not expect science to settle ethical issues; science can
provide information but cannot tell us what, if anything, to do with
At 287 pages, the book is not long, but it is densely packed with
ideas. Kagan illustrates his points with references that range from
literary to neurological, although their relevance is not always
obvious. His metaphors can be colorful and a little over the top. He
has an interesting tendency to anthropomorphize nature, in
particular as a feminine figure to be revealed:
The inability to know the future, a frustrating source of
uncertainty in the life sciences, and especially in studies of human
behavior, is the wall in the labyrinth that will not fall until
history, signaling its vulnerability, allows our hero to pass into
the next room to confront another barrier on the endless journey to
the center, where truth, reclining on a silk couch, waits patiently
to be touched.
I'm tempted to ask what truth is wearing.
Overall, Kagan comes across as optimistic—about human nature
("loyal, caring, and cooperative"), psychology's progress
to date ("extraordinary") and even prejudice at Harvard
("essentially gone"). Therefore it is somewhat surprising
that in his conclusion he issues a pessimistic forecast for the
future of psychology as a unified field, predicting a split into
neurobiological and sociocultural groups. Personally, I hope he is
wrong, for I fear that such a division would result in fewer
generalists and popularizers such as Kagan.
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Because penguins have been around for over 60 million years, their fossil record is extensive. Fossils that Dr. Ksepka and his colleagues have discovered provide clues about migration patterns and the diversity of penguin species.
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