Economic Sciences
A functional imaging study of cooperation in two-person
reciprocal exchange
Kevin
McCabe*,
,
,
Daniel
Houser*,,§,
Lee
Ryan*,¶,
Vernon
Smith*,, and
Theodore
Trouard*,
* Cognition and Neuroimaging Laboratories, University of Arizona,
Tucson, AZ 85721; Interdisciplinary Center for Economic
Science, George Mason University, 4400 University Drive, MSN 1B2,
Fairfax, VA 22030; § Department of Economics, McClelland
Hall 401, P.O. Box 210108, University of Arizona, Tucson, AZ
85721-0108; ¶ Department of Psychology, Psychology 312, P.O. Box 210068, University of Arizona, Tucson, AZ 85721-0068; and
Biomedical Engineering Program, AHSC 5302, P.O. Box
245084, Tucson, AZ 85724
Contributed by Vernon Smith, August 7, 2001
Cooperation between individuals requires the ability to infer each
other's mental states to form shared expectations over mutual gains
and make cooperative choices that realize these gains. From evidence
that the ability for mental state attribution involves the use of
prefrontal cortex, we hypothesize that this area is involved in
integrating theory-of-mind processing with cooperative actions. We
report data from a functional MRI experiment designed to test this
hypothesis. Subjects in a scanner played standard two-person "trust
and reciprocity" games with both human and computer counterparts for
cash rewards. Behavioral data shows that seven subjects consistently
attempted cooperation with their human counterpart. Within this group
prefrontal regions are more active when subjects are playing a human
than when they are playing a computer following a fixed (and known)
probabilistic strategy. Within the group of five noncooperators, there
are no significant differences in prefrontal activation between
computer and human conditions.
To whom reprint requests should be addressed.
E-mail: kmccabe{at}gmu.edu.
