1. Informed Consent Form for Intergroup Decision-Making
You are invited to take part in a study named Intergroup Decision-Making. The study is
designed to learn more about out how people make economic decisions in intergroup
contexts. David Sze and Brian Watson are conducting the study.
If you agree to be in this study, you will be asked to fill out some questionnaires and
complete an economic decision-making task. Your participation will take about 30 minutes,
and you will receive credit towards your course requirements or monetary compensation of
$5. When you complete the study, a verbal and written explanation of it will be provided.
Confidentiality of your research records will be strictly maintained by using only random
codes. The data from the study will be kept at least until 5 years after publication, as
recommended by the American Psychological Association. The researchers will destroy
collected data by shredding all paper questionnaires and deleting any electronic media.
Questions, comments, or concerns about the study can be directed to the principle
investigator, Dr. Saaid Mendoza (smendoza@amherst.edu, 413-542-2791, Merrill
Science 324).

2. Debriefing Form for Intergroup Decision-Making
The experiment you participated in today is part of a program of research
designed to investigate the expression of intergroup bias in the context of economic
decision-making games. Past research has demonstrated that individuals within these
games often fail to act in rational ways, such that their decisions are driven by concerns
of fairness rather than economic rationality. This current study examined how people’s
decisions could also be influenced by intergroup factors. In particular, we were interested
in investigating how responses to ingroup and outgroup members could be altered by
differential expectations of fairness.
Because we were interested in the possible expression of intergroup bias in
participants’ decisions, it was necessary for the study to include some deception. In
particular, participants were led to believe at the beginning of the experimental session
that the study was a joint research project between Amherst and Williams. In actuality,
the study was isolated within Amherst College. Furthermore, all of the interactions that
took place were offline and pre-determined by the experimenters. The college logo
avatars that were ostensibly used to protect the online identities of the participants were
never shown to anyone and simply served as a method for manipulating the apparent
group membership of their ‘virtual’ partners. This design allowed us to test the
hypothesis that participants would have higher expectations of fairness when interacting
with ingroup (Amherst) than outgroup (Williams) members and would therefore respond
accordingly when presented with unfair offers from them.
Thank you for your participation! Your time and effort is greatly appreciated and
will help us better understand how intergroup bias operates in social behavior. Such
research has important implications for theoretical and applied psychology. We ask that
you please do not tell anyone about this experiment. It is highly important that future
participants do not become aware of the details of the study.
We would like to stress that all your responses will be kept completely
confidential. All materials were prepared and will be coded in such a way as to prevent
any identification. Questions, comments, or concerns about the study can be directed to
the principle investigator, Dr. Saaid Mendoza (smendoza@amherst.edu, 413-542-2791,
Merrill Science 324).

3. Amherst College
Dean of the Faculty
ETHICS REVIEW FORM
(Please type)
Title of Research Project: Intergroup Decision­Making
Investigator(s): Saaid Mendoza, David Sze & Brian Watson email: smendoza@amherst.edu
phone: 413­542­2791
AC# 324 Merrill Science
Printed Name and Signature of Faculty Supervisor: Saaid Mendoza
Answer questions in spaces below and/or provide numbered answers on separate sheets.
1. ​Briefly describe the purpose of this study:
The proposed study is part of a program of research designed to investigate the expression of
intergroup bias in the context of economic decision­making games. Past research has
demonstrated that individuals within these games often fail to act in rational ways, such that their
decisions are driven by emotional or ideological factors rather than self­interests (Boyd et al,
2003; Fehr & Gachter, 2002). In the study being proposed here, we seek to extend this work by
exploring how intergroup processes might also bias decisions within this context. In particular,
we are interested in examining how people differentially uphold fairness norms as a function of
their interaction partners’ group membership.
2. ​Participants: Describe the number and type of participants, the source from which they will be recruited, the
method of recruitment. [Those under age 18, except college students, require written parent permission. ATTACH A
COPY OF YOUR PARENT PERMISSION LETTER, if appropriate].
A total of 80 Amherst College students will be recruited to participate in this study. Participants
will be recruited through the SONA website and will receive credit for their Psych 11
requirements or monetary compensation of $5.
Amount of time needed per participant: Approximately 30 minutes.
3. ​Describe the procedure (what participants will be asked to do) in detail:
[ATTACH COPIES OR DESCRIPTIONS OF MEASURES]
Participants will be told that they will be participating in a Amherst College and Williams
College joint research project. For this particular session, they will be told that they will be
interacting with a mixture of live and prerecorded data from students of these two schools. The
‘necessity’ of including pre­recorded data will be described as resultant from the logistics of
small college interaction. They will be making a series of economic decisions with other students
in the context of an online interactive game. Participants will be asked to fill out a questionnaire
that assesses their college identity. The strength of their college identity will be studied as a

4. moderating variable of the intergroup relationship in question. The collection of identity
information will also act to increase the salience of their college affiliation. They will then be
assigned avatars that represent their college affiliation. However, these avatars will never be
shown to anyone; they will simply serve as a method for manipulating the apparent group
membership of the participants’ virtual partners. Participants that told that they will be randomly
assigned to either be “Proposers” or “Responders” at the start the game. Despite the cover story,
after being assigned an avatar, all participants will be assigned to the role of responder in the
ultimatum bargaining game (see Guth & Tietz, 1990).
In the game, proposers decide how to divide a hypothetical sum of money (e.g., $20) with
their partners and responders decide whether to accept or reject the offer. If the offer is accepted,
each individual receives the amount agreed upon; if the offer is rejected, each individual receives
nothing. Though the game can have an iterative design, the negotiations in this study will be
one­shot deals with various partners in order to minimize concerns people may have about the
consequences of their decisions. Because we are interested in intergroup bias, participants in the
critical condition will be shown avatars of people with different college affiliations (Amherst
College and Williams College) which supposedly represent the prerecorded responses of their
‘partners’, but are in fact programmed by the experimenters. The severely polarized nature of
this relationship between these schools is conducive to the purpose of the study. In addition, after
the multiple exchanges are complete, participants will be asked to complete a questionnaire
judging the fairness of each proposal. This information will be used to measure the mediating
effects of perceived fairness on responses to proposals. This will allow us to examine whether
offers, acceptance rates, and perception of fairness differed by the college affiliation. They will
then be fully debriefed and thanked for their time, which should take approximately 30 minutes.
4. If the research requires any deception, provide explicit justification:
Because this study is interested in the effect of intergroup bias on decision­making, some
deception is involved in describing the purpose and design of the ultimatum game. However, the
procedures will be accurately described to the participants and they will be fully debriefed about
the deception at the end of the study.
5. Risk to participants: Given the fact that in any study it is possible for participants to experience some degree of
discomfort, anxiety, concern about failure, etc., what will you do to minimize the possibility that this will occur, and
how will you deal with it if it does occur?
There are no known risks associated with this study. The experiment is not expected to be
emotionally provoking.
6. How will you obtain informed consent?
[Describe procedure, and attach copies of forms or letters]
Participants will be informed at the time of recruitment and at the beginning of the study that
they will participate in an ultimatum game. In particular, they will be asked to make a series of
economic decisions with various interaction partners. The consent form will assure participants
of their anonymity and will remind them that they can skip any questions or stop at any point
during the study without penalty.
7. How will you debrief participants?

5. [Describe procedure, and attach copies of debriefing letter; if the research involves any​ ​deception, specifically
explain appropriate debriefing procedures]
After participants complete the experiment, they will be presented with general information
about the study and the researchers’ hypothesis. The study’s procedure and use of deception will
be thoroughly explained to the participants.
8. Participants' rights:
A: How will privacy be guaranteed? [Please include a description of how the data will be handled and
stored to insure privacy]
Participants will be assigned unique code numbers so that their names or any other identifying
information will not appear on any of the data collection materials. All materials will be stored in
a locked laboratory room within the Psychology Department, accessible only to the PI and his
collaborators for research purposes. Responses will not be examined during the laboratory
sessions; only pooled data from all participants will be analyzed. Data will be deleted and/or
shredded 5 years after their publication, as recommended by the American Psychological
Association.
B: How will participants' right to terminate or refuse participation be guaranteed?
Participants will be informed at the time of recruitment and at the beginning of the testing period
that they are free to stop at any point if they feel uncomfortable continuing with the study. The
right to terminate participation will also be stated in the consent form that participants will have
signed.
9. Student researchers' background which qualifies them to conduct research:
[Include names of relevant courses]
David Sze (2013) and Brian Watson (2013) are psychology majors at Amherst College, who
have taken four and five psychology courses, respectively. They have written several papers on
psychological concepts for their courses and have learned the principles underlying research
methodology and data analysis through their Statistics and Experimental Design course. Their
exposure to a wide variety of scientific articles within psychology has prepared them for aiding
in the collection of experimental data.
CHECKLIST
​_____ Attach copies of measures.
_____ Attach copies of informed consent, debriefing, parent permission letters.
_____ Make sure ALL researchers sign "Acknowledgment of Ethical Concerns" statement.
_____ SIX​ copies of this proposal and all attached documents to the Dean of the Faculty.

6. Acknowledgment of Ethical Concerns
for Student Researchers or Participant Observers*
In undertaking this research project, I commit myself to the following standards:
•Each student who is involved in conducting research is responsible for compliance with the American
Psychological Association's ethical code of conduct for research and/or the American Sociological and
American Anthropological Associations ethical guides to researchers. Since the research supervisor
(faculty member) is ultimately responsible for meeting guidelines, the student is required to inform the
faculty supervisor promptly of any potential ethical concerns or violations.
• Ethical practice requires the student researcher to inform each participant of all features of the research
that might influence willingness to participate and to explain all other aspects of the research about which
the participant inquires.
• Ethical research practice requires the student researcher to respect each participant's freedom to decline
to participate in research or discontinue participation at any time for any reason without penalty.
• Ethically acceptable research begins with the establishment of a clear and fair agreement between the
student researcher and research participant that clarifies the expectations of each. The student researcher
has the obligation to honor all promises and commitments included in that agreement.
• The ethical student researcher protects participants from physical and mental discomfort, harm, and
danger. All risk to the participant must be minimized and explained to the participant before she/he agrees
to participate.
• After the data are collected, the student researcher must provide the participant with an explanation of
the study (debriefing) and remove any misconceptions that may have arisen.
•Where research procedures may have undesirable effects on participants, the student researcher in
collaboration with the faculty advisor must remove or correct these effects, including any long term
aftereffects.
•All information obtained about participants is confidential. When the possibility exists that others may
obtain this information, ethical research requires you to inform participants of this before they give their
consent to participate, and that you give an explanation of what steps are being taken to protect
confidentiality. All data must be handled, stored, and discarded in a manner that insures the
confidentiality of each participant.
Name(s) of student researchers: ________________________________________
Signature(s): _______________________________________________________
Date: _____________________________________________________________

7. AMHERST COLLEGE
Protection of Human Subjects
CONSENT FORM
Title of Study: Intergroup Decision­Making
Investigator(s): Saaid Mendoza, David Sze & Brian Watson
The following informed consent is required for any person involved in research study. This study has
been approved by the Institutional Review Board for the Protection of Human Subjects at Amherst
College.
I understand that:
1. My participation is voluntary.
2. I may withdraw my consent and discontinue participation in this study (or any portion thereof) at any
time without bearing any negative consequences. I will receive full credit for participation regardless of
how much of the experiment I complete.
3. You have given me an explanation of the procedures to be followed in the project, and
answered any inquiries that I may have.
4. All of the information from this study will be strictly confidential. No names will be associated with the
data in any way. Providing my address to receive a report of this research upon its completion will also
not compromise the anonymity of the data. I understand that the data will be stored in locked offices and
will be accessible only to members of the researching group.
5. The results of this study will be made part of a final research report and may be used in papers
submitted for publication or presented at professional conferences, but under no circumstances will my
name or other identifying characteristics be included.
I have reviewed the procedures to be followed and hereby give my consent to participate in this research.
I also agree not to discuss the purposes and procedures of this study with anyone in order that the integrity
of this research is not compromised.
__________________________________________________Signature
__________________________________________________Print Name
__________________________________________________Date
Please send me a report on the group results of this research project upon its completion:
​YES NO
Address to which the report should be sent: ____________________________________

8. _______________________________________________________________________