Joshua D. Greene
Assistant Professor
Department of Psychology
Harvard University
William James Hall 1480
33 Kirkland Street
Cambridge, MA 02138
email:
jgreene-at-wjh-dot-harvard-dot-edu (replace "-at-" and "-dot-" as
usual)
phone: (617) 495-3898
office: William James Hall
1480
CV (PDF)
For more
information about my research and collaborators, please visit the Moral Cognition Lab
webpage.
Research and
Background
I study moral
judgment and decision-making using behavioral experiments, functional
neuroimaging (fMRI), and other neuroscientific methods. The goal
of my research is to understand how moral judgments are shaped by
automatic processes (such as emotional “gut reactions”) and controlled
cognitive processes (such as
reasoning and self-control). Much of my current work
is aimed at understanding these automatic and controlled processes in
more detailed funcitonal terms. I also have a new line of
research examining the cognitive nature of honesty and dishonesty,
which doubles as research on brain-based lie-detection. Much of
my research is
motivated by normative philosophical questions. I am currently
writing a book about the moral implications of our emerging scientific
understanding of morality.
Emotion
and Reason in Moral Judgment
Rationalist
philosophers such as Plato and Kant conceived of mature moral
judgment as a rational enterprise, as a matter of appreciating abstract
reasons that in themselves provide direction and motivation. In
contrast to these philospohers, "sentimentalist" philosophers such as
David
Hume and Adam Smith argued that emotions are the primary basis for
moral judgment. In more recent years, the rationalist banner has
been carried by developmental psychologists such as Lawrence
Kohlberg. Likewise, some contemporary researchers, most notably Jonathan Haidt, have emphasized
the importance of emotion in moral judgment. I think that emotion
and reason are both important forces in moral judgment and that their
respective influences have been widely misunderstood.
More specifically, I have proposed a "dual-process" theory
of moral judgment according to which characteristcically deontological
moral judgments (judgments associated with concerns for "rights" and
"duties") are driven by automatic emotional responses, while
characteristically utilitarian or consequentialist moral judgments
(judgments aimed at promoting the "greater good") are driven by more
controlled cognitive processes. If I'm right, the tension between
deontological and consequentialist moral philosohies reflects an
underlying tension between dissociable systems in the brain. Many
of my experiments employ moral dilemmas, adapted from the philosophical
literature, that are designed to exploit this tension and reveal its
psychological and neural underpinnings.
Moral
Dilemmas and the "Trolley Problem"
My main line of
experimental research began as an attempt to understand the "Trolley
Problem," which was originally posed by the philosophers Philippa Foot
and Judith Jarvis
Thomson.
First, we have the switch
dilemma: A runaway trolley is hurtling down the tracks toward
five people who
will be killed if it proceeds on its present course. You can save these
five people by diverting the trolley onto a different set of tracks,
one that has only one person on it, but if you do this that person will
be killed. Is it morally permissible to turn the trolley and thus
prevent five deaths at the cost of one? Most people say
"Yes."
Then we have the footbirdge
dilemma: Once again, the
trolley is headed for five people. You are standing next to a large man
on a footbridge spanning the tracks. The only way to save the five
people is to
push this man off the footbridge and into the path of the
trolley. Is
that morally permissible? Most people say "No."
These two cases create a puzzle for moral philosophers: What
makes it okay to sacrifice one person to save five others in
the switch case but not in
the foorbridge case?
There is also a
psychological puzzle here: How does everyone know (or "know")
that it's
okay to turn the trolley but not okay to push the man off the
footbridge?
According to my dual-process theory of moral judgment, our
differing responses to these two dilemmas reflect the operations of at
least two distinct psychological/neural systems. On the one hand,
there is a system that tends to think about both of these problems in
utilitarian terms: Better to save as many lives as
possible. The operations of this system are more controlled,
perhaps more reasoned, and tend to be relatively unemotional.
This system appears to depend on the dorsolateral prefrontal cortex, a
part of the brain associated with "cognitive control" and reasoning.
On the other hand, there is a different neural system that
responds very differently to these two dilemmas. This system
typically responds with a relatively strong, negative emotional
response to the action in the footbridge
dilemma, but not to the action in the switch dilemma. When this more
emotional system is engaged, its responses tend to dominate people's
judgments, explaining why people tend to make utilitarian judgments in
response to the switch
dilemma, but not in response to the footbridge
dilemma.
If you make the utilitarian judgment sufficiently
attractive, you can elicit a prolonged competition between these two
systems. Consider the crying
baby dilemma: It's war time, and
you are hiding in a basement
with
several other people. The enemy soldiers are outside. Your
baby starts to cry loudly, and if nothing is done the soldiers will
find you and kill you, your baby, and everyone else in the
basement. The only way to prevent this from happening is to cover
your baby's mouth, but if you do this the baby will smother to
death. Is it morally permissible to do this?
According to the dual-process theory, this dilemma is difficult because
it, like the footbridge
dilemma elicits a strong negative emotional response ("Don't kill the
baby!"),
while at the same time eliciting a comparably compelling utilitarain
response from the other system ("But if you don't kill the baby,
everyone dies.") Difficult dilemmas like this one tend to elicit
increased activity in the anterior cingulate cortex, a brain region
associated with "response conflict." And when people make
utilitarian judgments in response to these difficult dilemas, they
exhibit increased activity in anterior regions of the dorsolateral
prefrontal cortex.
The
Moral Significance of Moral Psychology
My interest in
understanding how the moral mind/brain works is in part driven by
good-old-fashioned curiosity, but I also harbor a moral, and ultimately
political, agenda. As everyone knows, we humans are beset by a
number of serious social problems: war, terrorism, the destruction of
the environment, etc. Most people think that the cure for these
ills is a heaping helping of common sense morality: "If only
people everywhere would do what they know, deep down, is right, we'd
all get along."
I believe that the opposite is true, that the aforementioned problems
are a product of well-intentioned people abiding by their respective
common senses and that the only long-run solution to these problems is
for people to develop a healthy distrust of moral common sense.
This is largely because our social instincts were not designed for the
modern world. Nor, for that matter, were they designed to promote
peace and happiness in the world for which they were designed, the
world of our hunter-gatherer ancestors.
My goal as a scientist, then, is to reveal our moral thinking for what
it is: a complex hodgepodge of emotional responses and rational
(re)constructions, shaped by both genetic and cultural influences, that
do
some things well and other things extremely poorly. My hope is
that by understanding how we think, we can teach ourselves to think
better, i.e. in ways that better serve the needs of humanity as a whole.
For a short introduction to some of these ideas, you can download this article. For a longer,
and more philosophically contentious, presentation, I recommend this article. Then there is
my philosophy dissertation,
which you are welcome to slog through. Finally, I am writing a
book about these issues, which I expect to be published in 2010.
I
also have a related paper about the problem
of free will and legal responsibility
(co-authored with my former advisor, Jonathan Cohen).
Book
I
am currently writing a book (Penguin Press, expected 2010) about
the moral and social implications of our emerging scientific
understanding of morality. This book is a much revised and
expanded version of my philosophy dissertation.
Dissertation
Greene, J. D. (2002). The Terrible,
Horrible, No Good, Very Bad Truth About Morality and What To Do About
It. Department of Philosophy, Princeton University. (advised by David
Lewis and Gilbert Harman) Download PDF
Journal Articles
Shenhav, A.S., Greene, J.D. (in
prep) Neural representations of
expected moral value and its components.
Shenhav,
A.S.,
Greene, J.D. (in prep)
Utilitarian calculations,
emotional assessments, and integrative moral judgments: Dissociating
neural systems underlying moral judgment.
Greene, J.D.,
Lowenberg, K., Nystrom, L.E., and Cohen, J.D. (in prep)
Neural dissociation between affective and cognitive moral disapproval.
Baron, J., Ritov, I., and Greene, J.D. (submitted) The duty to support
nationalistic policies.
Shariff, A.F., Greene, J.D., Schooler, J.W., (submitted) Beyond
retribution?: Effects of encouraging a deterministic worldview on
punishment.
Greene,
J.D., Lowenberg, K., Nystrom, L.E., Darley, J.M., and Cohen,
J.D. (submitted) Duty vs. the greater good: dissociable neural bases of
deontological and utilitarian moral judgment in the context of keeping
and breaking promises.
Greene,
J.D., Paxton, J.M. (2009) Patterns of neural activity associated
with honest and dishonest moral decisions. Proceedings of the National Academy of
Sciences USA, Vol. 106, No. 30, 12506-12511. Download
PDF
Paharia, N.,
Kassam, K.S., Greene, J.D., Bazerman, M.H.
(2009) Dirty work, clean hands: the moral psychology of
indirect agency. Organizational
Behavior and Human Decision Processes, 109, 134-141. Download PDF
Greene, J.D., Cushman, F.A., Stewart. L.E., Lowenberg, K., Nystrom,
L.E., and Cohen,
J.D. (2009) Pushing moral buttons: The interaction between
personal force and intention in moral judgment. Cognition, Vol. 111 (3), 364-371.
Download PDF Supplementary
Materials
Greene, J.D. (2009) Dual-process morality and the
personal/impersonal distinction: A reply to McGuire, Langdon,
Coltheart, and Mackenzie. Journal
of Experimental Social Psychology, Vol. 45 (3), 581-584. Download PDF
Greene, J.D.,
Morelli, S.A., Lowenberg, K., Nystrom, L.E., Cohen, J.D. (2008)
Cognitive load selectively interferes with utilitarian moral
judgment. Cognition,
Vol. 107, 1144-1154. Download PDF
Supplementary
Materials
Greene, J.D. (2007) Why are VMPFC patients more utilitarian?:
A dual-process theory of moral judgment explains. Trends in
Cognitive Sciences. Vol 11, No. 8, 322-323. Download PDF
Greene, J. D. ,
Cohen J. D. (2004) For the law, neuroscience changes nothing and
everything. Philosophical
Transactions of the Royal Society of London
B, (Special Issue on Law and the Brain), 359, 1775-17785. Download PDF
Greene, J.D.,
Nystrom, L.E., Engell, A.D., Darley, J.M., Cohen, J.D. (2004) The
neural bases of cognitive conflict and control in moral judgment.
Neuron, Vol. 44,
389-400. Download
PDF
Greene, J.D.
(2003) From neural "is" to moral "ought": what are the moral
implications of neuroscientific moral psychology? Nature Reviews
Neuroscience, Vol. 4, 847-850. Download PDF
Greene, J. and
Haidt, J. (2002) How (and where) does moral judgment work? Trends
in Cognitive Sciences, 6(12), 517-523. Download PDF
Greene, J.D.,
Sommerville, R.B., Nystrom, L.E., Darley, J.M., & Cohen, J.D.
(2001). An fMRI investigation of emotional engagement in moral
Judgment. Science, Vol.
293, Sept. 14, 2001, 2105-2108. Download PDF
Greene, J.D.,
Baron, J. (2001). Intuitions about declining marginal
utility. Journal of Behavioral
Decision Making, 14,
243-255. Download
PDF
Baron, J.,
Greene, J.D. (1996). Determinants of insensitivity to quantity in
valuation of public goods. Journal
of Experimental Psychology: Applied,
2, 107-125. Download
PDF
Book Chapters
Greene, J.D. (in press) The cognitive neuroscience of moral judgment,
in The Cognitive Neurosciences IV,
M.S. Gazzaniga, Ed. MIT Press, Cambridge, MA.
Cushman, F., Young, L., Greene, J.D. (in press) Our mutli-system
moral psychology, in The Oxford
Handbook of Moral Psychology, J. Doris, G. Harman, S. Nichols,
J.
Prinz, W. Sinnott-Armstrong, S. Stich, Eds. Oxford
University Press, Oxford.
Greene, J. D.
(in press) Social neuroscience and the soul's last stand, in
Social Neuroscience: Toward
Understanding the Underpinnings of the
Social Mind, A. Todorov, S. Fiske, and D. Prentice, Eds.
Oxford
University Press, New York. Download
PDF
Greene, J.D.
(2009) Fruit flies of the moral mind, in What's Next: Dispatches from the Future of
Science, M. Brockman,
Ed., Vintage, New York.
Greene, J. D. (2007). The secret joke of Kant's soul, in Moral
Psychology, Vol. 3: The Neuroscience of Morality: Emotion, Disease, and
Development, W. Sinnott-Armstrong, Ed., MIT Press, Cambridge,
MA. Download PDF
McClure, S.M.,
Botvinick, M.M., Yeung, N., Greene, J.D., Cohen, J.D. (2007).
Conflict monitoring in conflict-emotion competition, in Handbook of
Emotion Regulation, J.J. Gross Ed., Guilford Press, New York.
Greene, J. D. ,
Cohen J. D. (2006), For the law, neuroscience changes nothing and
everything, in Law and the Brain,
S. Zeki and O. Goodenough, Eds.,
Oxford University Press, New York. Download PDF (journal
version)
Greene, J.
(2005). Emotion and cognition in moral judgment: evidence from
neuroimaging, in Neurobiology of
Human Values, J.P. Changeux, A.R.
Damasio, W. Singer, and Y. Christen, Eds., Springer-Verlag, Berlin.
Greene, J.
(2005). Cognitive neuroscience and the structure of the moral mind, in
The Innate Mind: Structure and
Contents, S. Laurence, P. Carruthers,.
and S. Stich. Eds., Oxford University Press, New York. Download PDF
Bound