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
phone: (617) 495-3898
office: William James Hall
1480
CV (PDF)
(See below for
downloadable papers)
Research and
Background
I study moral
decision-making using behavioral methods coupled with neuroimaging
(fMRI). My research focuses on the interplay between emotional
and "cognitive" processes in moral judgment.
Emotion
and Reason in Moral Judgment
Rationalist
philosophers such as Plato and Immanuel 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 Plato and Kant, "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. My research program
aims at a synthesis of these two perspectives. In my experiments
I present people with moral dilemmas that, if I'm right, elicit a
complex combination of reasoned and emotional responses. To download an
increasingly dated review of the field of neuroscientific moral
psychology (co-authored with Jonathan Haidt) click here.
Moral
Dilemmas and the "Trolley Problem"
The moral
dilemmas that I use in my experiments are often adapted from
dilemmas devised by philosophers to probe our moral intuitions.
The most famous example of these is the "Trolley Problem," which goes
like this:
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. Now consider a slightly different dilemma. Once again, the
trolley is headed for five people. You are on a footbridge over the
tracks next to a large man. The only way to save the five people is to
push this man off the bridge 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 for the sake of five others in
the first case but not in the second case? But 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
bridge? My collaborators and I have collected brain imaging data
suggesting that emotional responses are an important part of the
answer. (Click here
to download the paper.)
According to our theory, this dilemma is difficult and uncomfortable
because it creates a conflict between a strong emotional response
(“Don’t kill the baby!”) and a strong "cognitive" response that points
in the opposite direction ("But if you don’t kill the baby, you gain
nothing and have much to lose.") Two findings from our most
recent neuroimaging study support this interpretation. First, we
have found that in response to difficult moral dilemmas such as this a
brain region associated with response conflict (the anterior cingulate
cortex, or ACC) exhibits increased activity, suggesting that the
difficulty associated with dilemmas such as this results from response
conflict and not just a need for extended computation. Second, we
have found that in response to dilemmas such as this brain regions
associated with cognitive control (dorsolateral prefrontal cortex, or
DLPFC, and inferior parietal cortex) exhibit greater activity when
people favor the promotion of the best overall consequences. In
other words, when people say, "Yes, it’s okay to smother the baby,"
they exhibit increased activity in parts of the brain associated with
high-level cognitive function.
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 biological and cultural forces, 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 an
article of mine that appeared in Nature Reviews Neuroscience by
clicking here.
For a more in-depth (and academically philosophical) treatment you can
download a copy of my dissertation,
a revised and expanded version of which will be published as book
(Penguin, expected 2009). For a paper describing a related
treatment of the problem of free will and legal responsibility
(co-authored with Jonathan Cohen) click here. For a
philosophically motivated account of the psychological underpinnings of
Kantian vs. utilitarian approaches to ethics, click here.
Background
and Training
I began doing
psychological research in 1992 as a first-year undergraduate at the
University of Pennsylvania, working with Jonathan Baron on a
study of the valuation of environmental goods. (Click here to download the
paper.) That year I also took a seminar-style Psych 1 class with Paul Rozin, which made
a lasting impression. I had gone to Penn to study business, and I
quickly realized that business was not for me. I transferred to
Harvard after my freshman year and became a philosophy major, but my
brief introduction to experimental psychology dramatically shaped my
experience as a philosophy student. I spent my summers at Harvard
doing independent philosophy research, first under the guidance of
economist-philosopher Amartya
Sen (who later employed me as his research assistant) and then with
Derek Parfit,
who later advised my undergraduate thesis, a philosophical exploration
of psychological biases in moral judgment. I arrived at Princeton's Philosophy
Department as a graduate student in 1997. During my first
year I collaborated again with Jonathan Baron, this time long-distance,
on a study designed to show that the intuition behind John Rawls'
influential critique of utilitarianism may be grounded in a tendency to
misunderstand utility--to think of utility as exhibiting diminishing
marginal returns of utility. (To download the paper click here.) After
passing generals the following year, I met Jonathan Cohen
and pitched to him the idea for what would eventually be our first
neuroimaging study of moral judgment. (To download the paper
click here.)
For the next three years, I split my time between my work as a
cognitive neuroscientist and my philosophy dissertation, advised by
the late
David Lewis and by Gilbert
Harman. I finished my philosophy degree in June of 2002, at
which point I joined the Cohen lab full-time as a postdoc, working with
Jonathan Cohen,
John
Darley, and Leigh
Nystrom on neuroscientific and behavioral studies of moral
judgment. I am currently writing a book based on my philosophy
dissertation.
Book
I
am currently writing a book (under contract with Penguin Press) about
the social and philosophical 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
Greene, J.D., Lowenberg, K., Nystrom, L.E., Darley, J.M., and Cohen,
J.D. (in prep) Saving lives vs. keeping promises: an fMRI investigation
of consequentialist and deontological moral judgment.
Greene, J.D., Lowenberg, K., Nystrom, L.E., and Cohen, J.D. (in prep)
Neural dissociation between affective and cognitive moral disapproval.
Shariff, A.F., Greene, J.D., Schooler, J.W., (submitted) Beyond
retribution?: Effects of Encouraging a Deterministic Worldview on
Punishment.
Greene, J.D., Lindsell, D., Clarke, A.C., Nystrom, L.E., and Cohen,
J.D. (submitted) Pushing moral buttons: The interaction between
personal force and intention in moral judgment.
Paharia, N., Kassam, K.S., Greene, J.D., Bazerman, M.H.
(submitted) Dirty work, clean hands: the moral psychology of
indirect agency.
Greene,
J.D.,
Morelli, S.A., Lowenberg, K., Nystrom, L.E., Cohen, J.D.
(in press) Cognitive load selectively interferes with utilitarian
moral judgment. Cognition.
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
Cushman, F., Young, L., Greene, J.D. (in press) Our mutli-system
moral psychology: Towards a consensus view, in The Oxford
Handbook of Moral Psychology, J. Doris, G. Harman, S. Nichols,
J.
Prinz, W. Sinnott-Armstrong, S. Stich, Eds. Oxford: Oxford
University Press.
Greene, J.D.
(in press) Fruit flies of the moral mind, in New Ideas from the
Next Generation of Scientists (working title), M. Brockman,
Ed.
Random House, New York.
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. Download
PDF
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 Pres, 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
Manamana
Please direct
any questions or comments about this webpage to Joe Paxton at the
following address: jpaxton-at-wjh-dot-harvard-dot-edu