Social Behavior- Game
Theory and Reciprocity
Georgia De Vito
BERG, J., DICKHAUT, J., & MCCABE, K. (1994). TRUST, RECIPROCITY, AND SOCIAL HISTORY. GAMES
AND ECONOMIC BEHAVIOR, 122-142. RETRIEVED NOVEMBER 16, 2014, FROM
HTTP://WWW.SCIENCEDIRECT.COM/SCIENCE/ARTICLE/PII/S0899825685710275
Video
https://www.youtube.com/watch?v=5adPymgvzfo
Overview

Economic models assume individuals act in own self
interest

Make decisions to benefit individual vs. group

Game Theory  should economic models consider
individual or group mentality

“Evolutionary models predict the emergence of trust
because it maximizes genetic fitness though myopic self
interest suggests cheating”
Hypothesis and Procedure


Hypotheses

Ma>0 then kb(3Ma)=0

kb(3Ma)>Ma
Double-blind Investment game

Complete anonymity, only play once

Subjects in room A decide how much of $10 to send to subject in room B, which will triple
reroute

Subjects in room B then decide how much of received money they will keep or send back to
room A

Nash equilibrium predicts no money would be sent

Not the case, why?
Conclusions from Study

Reciprocity exists as a basic element of human
behavior and that this is accounted for in the trust
extended to an anonymous counterpart


Shared social history strengthens the relationship
between trust and reciprocity


Self interest alone does not explain results
Higher average return growth than average sent money
Internalization of social norms
Critical Review

Interesting Notes

People are more trusting than
expected

A general shared social history
changes behavior to favor
group benefit mentality

Including trust and reciprocity
would allow for better
explanations of economic
institutions

Unanswered questions/ unclear

How does gender affect
trust/reciprocity?

What if the sender risked
personal loss?

Why is trust less dependent
on social history than
reciprocity?
Questions?
Thoughts?