Prisoner’s Dilemma
A scenario where cooperation and trust wins and blind pursuit of self-interest loses, is illustrated by the problem faced
by two accomplices locked in separate cells. Each is offered three choices by the police:
1.
if both confess to the charges, both will be jailed for five years
2.
if only one confesses, he will be freed but the non-confessor will be jailed for twenty years
3.
if neither confesses, both will be tried for a minor offence and will be jailed for one year
Prisoner’s Dilemma Games
Instruction and Record Sheet
We are going to play a card game in which everybody will be matched with someone in opposition. I will now give
each of you a pair of plain white cards, one labelled red and one labelled bla ck. You will be asked to play one of these
cards by holding it to your chest (so we can see that you have made your decision but not what that decision is). Your
earnings are determined by the card that you play and by the card played by the person matched with you. If you play
your red card, then your earnings in dollars will increase by $2, and the earnings of the person matched with you will
not change. If you play your black card, your earnings do not change and the dollar earnings of the person matched
with you go up by $3. If you each play your red card, you will each earn $2. If you each play the black card, you will
each earn $3. If you play your black card and the other person plays his or her red card, then you earn zero and the
other person earns the $5. If you play red and the other person plays black, you earn the $5, and the other person earns
zero. All earnings are hypothetical.
Period 1
Self’s card
Other’s card
Self
Other
R
B
$5
$0
R
R
$2
$2
B
B
$3
$3
B
R
$0
$5
To begin: Would you please choose which card to play and write the colour (R or B) in the first column of the table at
the end. Show that you have made your decision by picking up the card you want to play and holding it to your chest.
Every one finished? Now, I will pair you with another person, ask you to reveal your choice, and calculate your
earnings. Remember to keep track of earnings in the space provided below. Finally, please note that in period 2 you
will be matched with a different person, and payoffs will change ($3 becomes $8).
Period 2
Self’s card
Other’s card
Self
Other
R
B
$10
$0
R
R
$2
$2
B
B
$8
$8
B
R
$0
$10
In period 3, you will be matched with a different person and payoffs change again ($8 becomes $13), but you get to
play with him/her in the last three periods.
Period 3
Self’s card
Other’s card
Self
Other
R
B
$15
$0
R
R
$2
$2
B
B
$13
$13
B
R
$0
$15
Summary Table
Period
Your card
Other’s card
(R or B)
(R or B)
Your earnings
1
2
3
4
5
Total
For a recent paper on the prisoner’s dilemma see Pothos et al. (2011).
However, insights into the behaviour of prisoners in dilemma were obtained in situations that so famously carry their
name. A comparison of female inmates and students in a simultaneous and a sequential Prisoner's Dilemma. In the
simultaneous Prisoner's Dilemma, the cooperation rate among inmates exceed ed the rate of cooperating students.
Relative to the simultaneous dilemma, cooperation among first -movers in the sequential Prisoner's Dilemma increases
for students, but not for inmates. Students and inmates behave identically as second movers. Hence, they found a
similar and significant fraction of inmates and students to hold social preferences. In summary, inmates are found to be
more cooperative than students (Khadjavi and Lange, 2013)!
Dawes, R.M. and Thaler R.H. 1988. “Anomalies: Cooperation”, Journal of Economic Perspectives 2 (Summer): 187–
197. DOI: 10.1257/jep.2.3.187 URL
Holt C.A. and Capra M. 2000 “Classroom Games: a Prisoner Dilemma”, Journal of Economic Education 31 (Summer)
229-236. DOI: 10.2307/1183093 URL
Khadjavi, M. and Lange, A. 2013 “Prisoners and their dilemma”, Journal of Economic Behavior & Organization, 92,
163–175. DOI: 10.1016/j.jebo.2013.05.015 URL
Pothos E.M., Perry G., Corr P.J., Matthew M.R. and Busemeyer J.R. 2011 “Understanding cooperation in the
Prisoner’s
Dilemma
game”
10.1016/j.paid.2010.05.002 URL
Personality
and
Individual
Differences
51(3)
210-215.
DOI: