Neurological correlates of the (un)willingness to reward cooperation and punish non-cooperation

People often use punishment and reward to get people to cooperate more (e.g.,
to show more proenvironmental behavior or to get people to obey laws). People
are often more reluctant to punish non-cooperation than to reward cooperation.
Given the willingness to restore justice, on the one hand, and the reluctance
to inflict harm, on the other hand, indicates that there are not only
psychological processes at play that foster sanctioning (e.g, anger and
restoring justice), but also psychological processes that hamper sanctioning
(e.g., reluctance to harm). As such, it may very well be that people experience
a *motivational conflict* when they punish others* non-cooperative behavior,
but not when they reward others* cooperative behavior.

In the current study we will examine this motivational conflict by studying
brain regions associated with conflict when people punish and reward others.
This is difficult (if not impossible) to study with behavioral measures. For
this reason, we use fMRI to examine this internal conflict that people may
experience. This way, we provide more insight in when and why people are
reluctant to punish others' cooperative behavior.

The study uses an experimental design. Participants will be presented with
cooperative and non-cooperative choices of unknown others, and participants
objective is to either punish these others by taking away money, reward them by
provinding them with money, or do nothing. We will measure brain activation
using functional Magnetic Resonance Imaging (fMRI) while they are performing
the task.

There are no risks associated with behavioral testing except the occasional
possibility of some boredom or fatigue. Testing will stop if a subject displays
frustration or appears tired.
There are no known risks associated with participating in an fMRI study. This
is a noninvasive technique involving no catheterizations or introduction of
exogenous tracers. Numerous human subjects have undergone magnetic resonance
studies without apparent harmful consequences. Radiofrequency power levels and
gradient switching times used in these studies are within the FDA approved
ranges. Some people become claustrophobic while inside the scanner and in these
cases the study will be terminated immediately at the subject's request. The
only absolute contraindications to MRI studies are metal implants, intraocular
metal and heart arrhythmia. Relative contraindications include pregnancy and
claustrophobia. Subjects who may be pregnant, who may have metallic foreign
bodies in the eyes or head, or who have cardiac pacemakers will be excluded
because of potential contraindications of MRI in such subjects.

Although there is no direct benefit to the participants, the proposed research
is expected to make a significant contribution to our understanding of the
neural mechanisms underlying conflict and reward processing. Ultimately, this
can be beneficial for various practical purposes, including the treatment of
mood disorders which are associated with dysfunctional conflict and reward
processing. In terms of scientific contribution, the study will be the first
study to investigate the neural basis of interactions between reward and
conflict processing. The importance of the benefits gained from this research
far outweighs the minimal risks involved.