Intuitive cooperation and selfish thoughts

INTUITIVE COOPERATION AND SELFISH THOUGHTS
Intuitive cooperation and selfish thoughts:
Are we automatically inclined to cooperate with others?
A replication study of Rand et al. 2012
J.W.M. Schuivens
Bachelor thesis: Psychology and Society.
17-12-2015
Supervisor: Anthony M. Evans. Tilburg University

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Abstract
In 2012 researchers Rand, Greene & Nowak studied and analyzed ten studies in which
participants had to take part in economic games in which their reaction time was measured.
They found a strong positive causal relation between intuitive decision making and
participants’ cooperation rate. Replication studies of this experiment did not find this relation,
or not as strong as mentioned in the original paper. The effect, if there is one, seems difficult
to replicate and does not seem to apply within all cooperative settings. This study has used
one of the original experimental designs in order to achieve the same results Rand et al. 2012.
This design featured a public goods game and a multitude of personality, trust and experience
measuring questions. For the public goods game one condition had to decide within 10
seconds and the others condition after ten seconds. Using the same method on naïve
psychology students of Tilburg University (N = 152) who participated in a public goods game
did not yield the same results. The current study did not find a strong positive relation
between intuitive decision making and cooperation, but found a null effect instead. There was
no significant difference between the two conditions. A large number of participants did not
obey the rules of the experiment but analyses show that did not ruin the current study.
Multiple variables such as age, gender, trust and experience were analyzed to see if they can
predict a participant’s cooperation rate but did not find any variable which can explain when
and why participants cooperate more.

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Introduction
Cooperation has been the subject of numerous studies over the years (Martinsson,
Myrseth & Wollbrant, 2014. Nowak, 2006. Nowak, 2012. Rand, Greene & Nowak, 2012.
Rand, D.G., Nowak, M.A., 2013a. Rand, Peysakhovich, Kraft-Todd, Newmann, Wurzbacher,
Nowak & Greene, 2014. Verkoeijen, P.P.J.L., Bouwmeester, S. 2014. ) and what its effects
are on human nature. Cooperation does seem the antithesis within evolution (Nowak, 2012).
Evolution is based on a fierce competition between individuals and should therefore only
reward selfish behavior (Nowak, 2006). Yet cooperation is abundant in nature and appears to
be involved in all great constructive steps of life on earth (Nowak, 2012). These two
statements reflect the division among people and scientists on whether the human nature is
cooperative or selfish. It is possible that some people believe that we, as humans, are inclined
to act selfishly and need to choose to act cooperatively. Selfishness could be regarded as an
impulse, as mentioned in Martinsson, Myrseth & Wollbrant (2014), and cooperation, within a
fair context, could be considered moral or social thoughtful behavior. Rand et al. published a
paper in 2012 claiming to have found the opposite effect: people are intuitively inclined to
cooperate and when given the chance to reflect more inclined to act selfishly. To understand
the weight of this claim there must first be an overview of cooperation and how it is shaped
within human behavior.
To understand the (human) nature of cooperation there must first be a clear definition
of cooperation. Cooperation is defined as: ”One individual pays a cost for another to receive a
benefit (Rand & Nowak, 2013a) with the characteristic that defectors have no costs and do not
deal out benefits (Nowak, 2006). There are multiple mechanisms of cooperation which help
us to understand the evolution of cooperation and what shape cooperation can take. There are
five mechanisms of cooperation: direct reciprocity, indirect reciprocity, spatial selection,
multi-level selection and kin selection. The following definitions of these five mechanisms are

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retrieved from Nowak, 2006. Direct reciprocity is based upon multiple (cooperation)
encounters with others. A simple example would be tit-for-tat: you help me, I help you.
Sometimes random mistakes can occur caused by ‘noise’ which can lead to someone
accidentally not reciprocating. This error can explain the evolution of forgiveness (Nowak &
Sigmund, 1992). Indirect reciprocity spreads through (positive) reputation. There are repeated
encounters in a population of individuals, some are observed by others, some are not.
Information about those encounters spreads through communication, thus affecting someone’s
reputation. A good reputation will lead to more trust, which leads to more cooperation and
vice versa. Indirect reciprocity is a major factor in the emergence of moral systems in human
societies. Spatial selection is based upon the structure of the population. Strategies that are
successful in a well-mixed population, where everyone interacts with everyone else equally
may not win in a more structured population and vice versa. Multi-level selection states that
there is not only competition between individuals but between groups as well. Depending on
the population, or group, one is placed in determines the cooperation. Kin selection is a
mechanism of cooperation based upon kin recognition. One is more inclined to help a (close)
family member rather than a stranger. These five mechanisms can individually, or together,
explain how humans cooperate, when reciprocity is involved. Cooperation without
reciprocity, between strangers, is not explained through these five mechanisms.
Economists explain the low reward behavior of people (within laboratory settings)
with social preferences (Wilson, 2010). Social preference is cooperation; a person could
prefer to cooperate within social settings. Evolutionary game theoretic models do often try to
shed light on the issues of origin and change of prosocial behavior but often without explicitly
connecting to specific models of social preferences (Peysakhovic & Rand, 2013). Biologist
Michael Ghiselin (1974) takes the position that social preferences are culturally determined
rules and do not lie within the human nature. Others, such as primatologist De Waal (1996)

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argues that we, together with primates and some other species, have a biologically determined
sense of justice and capacity for experiencing empathy and sympathy, which in turn are
crucial building blocks for morality. Then, he argues, if other primates, with less cognitive
capacity and less developed cultures, have these capacities, it appears clear that human
morality and various kinds of social preferences cannot be explained solely in terms of
culture. Martinsson, Myrseth & Wollbrant (2014) propose that cooperation is positively
associated with self-control. Cooperation can surface as the result of the impulse to act greedy
and the better judgment to act prosocially. As such, the question of acting selfishly or
cooperatively becomes one of self-control and the ‘stronger’ the individual, the more
cooperation we can expect. However, self-control matters only to the extent that the
individual recognizes the decision at hand as a self-control conflict. The dual-process theory
is relatable to the ‘self-control hypothesis’ of Martinsson, Myrseth & Wollbrant (2014) as the
dual process theory proposes two processes used when making a decision: automatic, more
impulsive and deliberate, more cognitive or controlled decision making. The nature of
cooperation is difficult to determine, whether in be cultural, within our nature or a matter of
self-control. Rand et al. 2012 proposes and researched the dual process theory approach
towards cooperation.
Rand et al. (2012) researched the question of whether or not cooperation is an
automatic, intuitive choice, or a controlled, deliberate choice. These two choices are based on
the dual process theory. According to Rand et al. (2012) a decision can be reached through
two different ways, or as a result of two different processes. The two processes consist of an
implicit (automatic or intuitive) unconscious process and an explicit (controlled or deliberate),
conscious process. The researchers proposed and tested the theory that cooperation is, in
general, advantageous in everyday life, which leads to people acting cooperatively from
intuitions. Deliberation, by contrast, adjusts behavior to what is the most beneficial in the

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given situation the person is in. They call this the “social heuristics hypothesis.”
The social heuristics hypothesis, or SHH, proposes that people tend to internalize
social norms as automatic behavioral responses. People develop their intuitions in the context
of daily life, where cooperation is typically advantageous (Rand et al., 2012). Yet it is also
possible people are intuitively non-cooperative if their automatic responses are based on
situation where self-preserving behavior was more advantageous (Rand et al., 2012).
Intuitive responses are more stable throughout time but deliberate responses are not.
Deliberative, more reflective processes may override automatic responses in situations where
we are allowed to reflect on this context and determine what is more advantageous than
cooperating.
To research whether the SHH is correct with regards to cooperation Rand et al. (2012)
examined participants decision time in one-shot public goods games, one-shot prisoners
dilemmas, repeated public goods games and repeated prisoners dilemmas with different
manipulations in rewards and punishments within the settings. The researchers performed and
analyzed data from ten studies. The results the researchers found show strong evidence that,
on average, time pressure increases cooperation relative to time delay. There is a causal
relation between time pressure and cooperation. Rand et al. call this causal relation the
intuitive cooperation effect. The researchers stated that the effect can be strongly positive,
positive or a null effect but there is no negative effect (Rand et al. 2012). The deciding factor
for these results, experience or, for example, trust has not been determined.
In 2014 when Rand et al. tried to replicate the effect by examining 15 studies featuring 6,910
decision they found that the effect decays over time. The researchers concluded this was due
to experience with public goods games, allowing participants to feel more comfortable within
the experiment and increasing the chance they can reflect more on their choice.
Researchers Tinghög et al. (2013) reviewed Rand et al. (2012) claims and research and

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stated a number of problems. The first problem is the exclusion of 50 percent of the
participants who failed to respond in time. This has led to an increase of the intuitive
cooperation effect and was controlled for in an incorrect way by Rand et al. (2012), according
to Tinghög et al. (2013). If done correctly, the effect they had found would not be significant.
Tinghög et al. (2013) performed 5 experiments of their own. Experiment 1 used a different
design. Participants had to choose to either keep ‘X’ amount of money, or donate a larger
amount to the group. In experiment 2-4 they made participants decide within 7 seconds, and
performed the experiments with Swedish, American and Austrian students. In experiment 4
they made participants wait for 20 seconds before deciding. Tinghög et al. found a negative
effect in experiment 2-4, but this was not significant. In experiment 5 they had a one-shot
public goods game with six different treatments. Two of the treatments used were the same as
Rand et al. (2012), but with binary decisions. The remaining four were identical to one
another, with the exception that in two of these treatments information was given before the
public goods game to see if phrasing of the question could prime the participants. For
experiment 5, in all six treatments, they found a null effect.
Verkoeijen & Bouwmeester (2014) also expressed critique towards Rand (2012)
paper. They ran their own 3 separate experiments using eight comparisons. On four they
found a small positive effect, on three they found a negative effect and on one they found a
null effect. In experiment 1 they had the time pressure and time delay condition, participants
knew what the others donated, and used humans and computers (A.I.) resulting in a 2x2x2
design. In experiment 2 they manipulated the use of the text box and who kept track of time:
Experiment 2a was a copy of Rand 2012 design, with the difference in the use of a text box
versus slider bar for donation amount and time being controlled by the experimenter.
Experiment 2b was the same as 2a except the use of a slider bar. 2c was an almost exact copy
of Rand 2012 by using a slider bar and time being controlled by the participant. Experiment 3

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was the same as experiment 2c while controlling for experience by using only naïve
participants. In all of these three experiments they failed to find the same results as Rand.
The effect Rand et al. (2012) has found seems hard to replicate, by others and by Rand
et al. (2014) themselves. This paper has taken one of Rand et al. (2012) design and the
expectation is that it will yield the same results as the original paper.
Rand, Greene and Nowak (2013b) replied to Tinghög et al. critique by saying that
there are only problems stated with two of the ten experiments. They analyzed the data once
more without the exclusion of participants and still found a positive significant result. The
null effect found by Tinghög et al. is contributed as study-to-study variation and that
experience has an effect on the decay of the time pressure effect.
For Verkoeijen & Bouwmeester (2014) no academic reply has been published (yet),
but there was a discussion on rolfzwaan.blogspot.nl. The website is hosted by a researcher and
colleague who wrote an article on Rand et al. (2012) results and the results of Verkoeijen &
Bouwmeester (2014). On the website David Rand has responded to the critique by stating that
there is a moderating effect of experience, reproducing the pattern seen over two years ago
(referring to Rand et al. 2012) in a single study using experience moderator (retrieved from
rolfzwaan.blogspot.nl/2014/05/are-we-intuitively-cooperative-or-are.html).
This study tries to add to the scientific discussion on intuitive cooperation. Using a
study design similar to Rand et al. 2012 the expectation is to find the same results. The
hypothesis is that participants who have to make a quick, intuitive decision are more likely to
cooperate than participants who can make a slower, deliberate decision. This effect will only
occur if the participant does not have previous experience with similar economic games.

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Method
The sample consisted of 152 Tilburg University students. All of the students were Psychology
students and the majority of the participants were in their first year. Students were recruited
through the university’s participation hours program and got 0,5 hours credit as a reward for
the participation. The study ran for two weeks at the start of the study year and, due to a low
number of participants, another additional week a month later.
Grouping
The study was conducted when at least eight participants showed up for the study. When there
were eight or twelve participants they were randomly placed in groups of four. Participants
were first gathered from the waiting room and placed within a lab cubicle. Within the lab
cubicle there were number sheets placed, at random, by the researchers. These numbers were
connected to a certain group in which the participants would be placed. Participants were not
aware of which group they, or others, were placed in.
If there was no way to make a group of four with the (remaining) participants they were
guided to the other lab to be part of a back-up study. These participants were told they could
participate by registering again at a later time and date.
Experience
The participants used in the sample were, as before mentioned, first year Psychology students.
Before the study there were no other studies the first year students could have participated in,
with the possible exception of the introductory ‘Test week’ experiment. Participants of the
last, later week could have done additional experiments but this would be such a low number
they could not be considered as an experienced participant.

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Survey
After reading and agreeing with the consent form the participants received an instruction
about the public goods game they were about to participate in. Within a group of four
participants every participant “received” 400 eurocents. Of these 400 cents the participants
were free to decide how much they wanted to keep and how much they wanted to contribute
to the group ‘pot’. The amount in the group pot would be doubled and divided amongst all
four group members. The money they kept for themselves was not doubled and could not be
taken. After the instruction the participants started the public goods game. The condition
“Time pressure” was asked to make their donation decision within 10 seconds, reflecting the
intuitive choice/process. The other, “Time delay” condition, was asked to make their decision
after 10 seconds, reflecting the deliberate choice/process. After the game was finished the
participant was asked some comprehension questions, such as “With what donation would the
group have received the biggest payout?” and asked about their motivation on why they gave
the amount they did.
The participants were also asked questions which measured their individualism, collectivism,
family values and their tendency to work with others. The complete survey can be found in
Appendix 1.
Amount donated
The cooperation rate is represented by the amount a participant donated to the group pot. A
donation of 400 cents equals a full 100 percent (1.00) cooperation, 200 cents equals 50% (0.5)
and 0 cents equals no cooperation (0).

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Motivation
The participant’s motivation was coded by both researchers at the same time. The motivations
were randomized in order and did not include the actual donation given by the participant.
The researchers coded motivation within four categories: self-focused, selfless, trust in group
and distrust in group. Example questions of these four categories are, respectively: “I gave a
low donation as this would give me a higher payout”, “I gave a high donation as this would
lead to a higher payout for the group as a whole”, “I think the rest of the group participants
will donate a high amount” and “I don’t think the group participants will donate a lot.” It was
possible to score on positive on one to all four of the categories. It was also possible a
motivation of a participant did not score on any of the categories. A score of all four
categories can be viewed as “ambiguity.” A score on none of the four categories can be
viewed as “other.”
Bonus
After the experiment participants received their 0,5 hour credit and got to keep their earnings
from the public goods game. These were handed within in the booth they were sitting in. The
money was handed to them via closed envelope.

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Results
Coding
The questions and their respective scores regarding experience, trust, individualism,
collectivism, value of family and need for competition were combined to a mean total score
for each variable. Experience was combined and divided between two variables: Experience
with public goods games (ExperiencePGG) and experience with scientific experiments
(ExperienceGeneral). These questions were rated on a scale from 1 to 5. Trust question came
in three different forms with three different phrasing of the questions and three different
scales. These questions were recoded to the same scale and combined to two variables. One
variable included all of the trust measuring questions, (TrustOverall) and one variable
excluded two of the trust questions which proposed a preference between two options, where
the other questions asked about agreement with a statement (TrustExclusion). Even though
the Cronbach’s alpha of all the trust questions was sufficient (Cronbach’s alpha = .74) this
separation was done to see whether or not these two questions were a disruptive factor. Both
trust variables were rated on a scale from 1 to 10.
Participant’s motivation was coded on four variables: self-focused, selfless, trust in group and
distrust in group.1
Exclusion
Three participants were excluded from the study because, based on their motivation text, did
not understand the public goods game. 26 participants were excluded from the study because
they failed the comprehension questions, suggesting they as well did not understand the game.
The remaining sample consisted of N = 123.
1 Further explanation of the four variables for motivation is mentioned within the Method section of the paper.

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Analyses
The sample, N = 123, consisted of 28 males and 95 females. Their average age was 20 (M
=19.76) years (SD = 1.93). Age and gender did not influence the amount donated (Age: r
(121) = -.66, p = .55. Gender: r (121) = .04, p = .63). Of the 123 participants 63 were placed
within the “Time Pressure” condition and the remaining 60 in the “Time Delay” condition.
The time pressure condition was compared to the time delay condition to see if there is
a significant difference between the amount donated. The time pressure condition donated an
average amount of M = .57 (SD = .34) and the time delay condition M = .61 (SD = .27), there
was no significant difference between the means of the two conditions t(121) = -.74, p = .46.
This null effect is represented in figure 1.
An independent t-test analysis was used to see if there was a difference in reaction
time between the two conditions. As expected, there was a significant difference in reaction
time between the two conditions t(121)= -5.65, p < .001. However, not all participants of the
time pressure condition obeyed the “10 second rule”, meaning they made their decision after
ten seconds. The time pressure condition had 63 participants. Of these 63 participants there
were 43 who disobeyed the “10 second rule” with the remaining 20 obeying the rule . The
average amount2 the obeying participants gave was M = .62, (SD = .38) and the average
amount the disobeying participants gave was M = .50, (SD = .25). An independent t-test
sample showed that these means do not significant differ from one another t(61)= 1.381, p =
.172. The researchers experimented with expanding the ten second rule to 15 seconds. In this
case 25 participant disobeyed the rule and 38 obeyed. The mean donation of the obeying
participants was M = .66 (SD = .34) and the disobeying participants was M = .54 (SD = .33).
2 Amount given is represented from a scale of 0 to 1.00. 0 means a participant donated no money, and did not
cooperate. 1.00 means a participant donated the entire amount of 400 cents and cooperated to the full extent
within the experiment

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An independent samples t-test showed no significant differences between the means of the
two groups t(61) = 1.358, p =.18.Obey or disobeying the ten second rule did not influence the
amount donated. For the Time Delay condition only one participant made his decision within
10 seconds and does not influence the rest of the results.
Figure 1. Mean percentage donated between the two time constraint conditions.
The boxplots shows that the mean donations of the two conditions are roughly the
same, based upon the almost equal level medians. The time pressure condition
……………………………participants varied with their donation given, shown by the tall boxplot of this
……………………………condition, suggesting that there is no effect of the time pressure and no difference
between the two conditions.
To check whether reaction time and not the condition could predict the cooperation
amount a correlation analysis was performed with amount donated and reaction time overall.
No correlation was found r(121) = -.06, p = .48. To provide a clear overview of the null effect

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of reaction time on percentage donated, or cooperation rate, is represented in figure 2.
Figure 2. Overall effect of reaction time on overall percentage donated by all participants.
The figure shows no correlation between reaction time and percentage
donated based upon the spread of dots shown.There is no effect of reaction
time on amount donated.
Experience was hypothesized to be disruptive or moderating variable for the time
pressure effect, or intuitive cooperation effect. The participants were scored on the experience
they had with public goods games and experience they had with being a participants of
scientific experiments. Participants in the time pressure condition had an average PGG
experience of M = 2.54, (SD = 1.16) and time delay participants had M = 2.43, (SD = 1.05).
General experience of the time pressure participants was M = 1.46, (SD = 1.77) and time

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delay participants M = 1.72, (SD = 2.24). Participants in both condition had neutral
experience with PGG. This result is interpreted as that participants had, on average, somewhat
experience with PGG. General experience with scientific experiments of the participants was
low, but they were not completely naïve to scientific experiments. To research the level of
experience with the amount donated a correlational analysis was performed. This result
revealed no significant correlation between the variables (Amount Given x ExperiencePGG:
r(121) = .07, p = .42 & Amount Given x ExperienceGeneral: r(121) = -.11, p = .22).
Trust, like experience, was considered to be a possible predictive factor of
cooperation. Participants of the time pressure condition had an overall trust score of M = 6.18
(SD = 2.12) and time delay participants had a score of M = 5.71, (SD = 2.16). The mean
overall trust scores did not significantly differ from one another t(121) = 1.189, p = .237. The
overall trust score did not predict the amount donated to the common pool (Amount Given x
TrustOverall r(121) = .10, p = .3). To check whether or not the two preference trust questions3
had a significant effect on the trust scores of participants these analyses were repeated with
the other trust variable. Participants of the time pressure condition had a trust score of M =
5.94 (SD = 2.64) and time delay participants M = 5.50, (SD = 2.63). These means did not
significantly differ from one another t(121) = 1.013, p = .313. As expected the trust variable
with two questions excluded did not predict the amount given, r(121) = .07, p = .44.
The survey measured four personality variables: Individualism, collectivism, value of
family and need for competition. The regression results are represented within table 1.
The table shows the regression between the personality variables and the amount donated,
providing an overview which variables have a correlation with amount donated and whether
or not this correlation is significant and if it is positive or negative.
Need for competition and individualism correlated with one another r(121) = .27, p = 0.003.
3 These two questions arediscussed in the ‘Coding’ paragraph of the Results section.

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Table 1.
Results of the linear regression analyses of personality variables by amount donated
Personality variables T P B SE B Β
Individualism -.775 .44 -.024 .032 -.069
Collectivism 3.515 0.001** .103 .029 .317**
Value of family -1.621 .108 -.046 .029 -.146
Need for competition -1.717 .089 -.039 .023 -.156
** = signicant at the p <.001 level.
Note: R2 = . 16.
Motivation was coded on four variables: self-focus, selfless[ness], trust in
group and distrust in group. The regression results for both conditions are represented within
table 2 for the Time Pressure condition and table 3 for the Time Delay condition. Correlation
analyses showed there is a correlation between self-focus and selfless (r(121) = -.32, p <
.001), self-focus and trust in group = (r(121) = -.194, p = .31), selfless and distrust in group
(r(121) = -.195, p = 0.03) and lastly, trust in group and distrust in group (r(121) = -.18, p =
0.04).
Table 2.
Results of the linear regression analyses of motivation by amount donated for the
Time Pressure condition
Motivation T P B SE B Β
Self-focus -1.767 .083 -.131 .074 -.192
Selfless 5.11 0.0001** .394 .077 .578
Trust in group -1.141 .259 -.123 .108 -.118
Distrust in group -1.727 .09 -.141 .082 -.181
** = significant at the p < .001 level.
* = significant at the p = 0.05 level
Note: R2 = .38.

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Table 3.
Results of the linear regression analyses of motivation by amount donated for the
Time Delay condition.
Motivation T P B SE B Β
Self-focus -1.734 .088 -.101 .059 -.189
Selfless 2.895 .005* .168 .058 .307
Trust in group 2.09 .041* .134 .064 .223
Distrust in group -2.318 .024* -.048 .021 -.247
** = significant at the p < .001 level.
* = significant at the p = 0.05 level
Note: R2 = .38.

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Discussion
Reaction time
Reviewing the results that are found with this study there are no time constraint effects
on cooperation. The two different conditions vary in reaction time, but not in the amount
donated, or cooperation rate. Disregarding the guidelines of the conditions, by expanding the
time pressure condition to 15 seconds rather than 10 seconds does not reveal a positive causal
relationship between condition and amount donated as well. Looking at the overall reaction
time, fully disregarding the guidelines of the conditions, also does not show us any effect of
reaction time one amount donated.
Predictive variables
Predicting variables for cooperation were mostly not significant for amount donated.
Trust, experience, age, gender and 3 of the 4 personality variables did not yield significant
correlation in regards to amount donated. The significant predictive variables found cannot
explain a possible intuitive cooperation effect. Collectivism was found to be a predictive
value of cooperation. This is not strange, as collectivism is dependents on a good group
cooperation; without it, it cannot exist. The effect of collectivism on cooperation was
previously found in Wagner’s (1995) study. A belief that the group will be distrustful, or
unfair within the public goods game proved to be significant for the donation amount,
providing a negative correlation between the motivation and amount donated. Once again, this
is not strange as cooperation would be low in a distrustful group, based upon the spatial
selection theory of Nowak (2006). Selfless behavior had a positive significant relation with
amount donated for both time pressure and time delay condition. Selflessness could be viewed
as altruistic, and therefor the highest level of cooperation. However Dunn et al. (2009) found

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that people experience personal happiness when giving money to others, suggesting that
selfless behavior is not always done for the group. This could explain why selflessness is
significant for both condition; it is a more complex motivation than would seem. For the time
pressure condition only selflessness was significant, but for the time delay condition
selflessness, trust in group and distrust in group were significant. The time delay condition
had more time to think and could therefor consider the (possible) actions of the group they are
in. Trust in group had a positive relation with amount donated and distrust had a negative
relation. This study would seem to suggest that cooperation occurs randomly, with the
predictive values being so strongly associated with cooperation but they do not provide us
with new, previously found insights.
Time pressure disobeyed
A major problem of this study were the disobeying participants. A large number of the
participants in the time pressure condition did not reach their decision within ten seconds.
This means the ten second rule from Rand et al. (2012) study did not work within this study
design. Even though the participants disobeyed the rules there was no significant effect of this
rule breaking on amount donated. Therefore, however unfortunate this may be, it is not a
reason to disregard this study or its results.
Possible future solution for the disobey problem
A possible way to increase the chance of participants obeying the condition’s rule
could be by framing the experiment in an appropriate way or priming participants before the
game. Participants of the time pressure condition could first read a text of situation in which
the intuitive decision was the best decision. Participants of the time delay condition could read
a text in which a deliberate decision was the best decision. This will frame either decision,

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depending on the condition, to be the best way to make a decision. The expectation would be
that the intuitive cooperation effect would be stronger as behavior tends to depend on whether
information is given in a positive or negative light as well as the wording used in the
experiment (effects of framing; Andreoni (1995), Sonnemans et al. (1998), and Cubitt et al.
(2011), Bardsley (2008)); for effects of different wordings see Ross and Ward (1996), and
Liberman et al. (2004).
Using a Likert scale, as opposed to the slider bar could increase the chance, but limits
the full free choice of donation. In the study there were very specific donations such as 243
cents and it might be possible participants do not distinguish much between a donation of 243
and 250. Another argument to use this, instead of the slider bar, is because all intuitive
cooperation studies (Verkoeijen & Bouwmeester, 2013. Rand et al., 2012. Tinghög et al.,
2013) analyse percentage of cooperation or percentage donated; this study is no exception.
Emphasizing that participants will actually receive the money might also bring
different results. A lot of participants expressed confusion and surprise when actually receive
the money they earned from the experiment. This is also found in the answers given when
asked if the participants thought the experiment featured some misleading aspects; a number
of participants stated that they did not believe to actually receive money. Explicitly stating,
for example, “You’ve now received 4 euro’s/400 cents with this study. The experimenter will
hand you your money at the end of the study, but you must first enter an economic game with
three other participants, which will give you the chance to increase the pay-out for you and
the group as a whole.” could help counter this.
Naïve or low experienced participants
Rand et al. (2014) has stated the results are difficult to duplicate because his original
respondent pool, the MTurk, has become too experienced with the study. A replication study

21
by Verkoeijen & Bouwmeester (2013) with naïve MTurk participants could not replicate the
results of Rand. This study, using naïve participants with little experience with the task and
little experience with scientific experiments has to disregard this claim. Experience does not
seem to affect the intuitive cooperation effect.
Trust
The level of trust did not affect or predict the intuitive cooperation effect or the
amount donated to the common pool. However, the trust questions were asked after
participants completed the public goods game, thereby letting their actions influence their
answers as a way to avoid cognitive dissonance. Placing the questions before the public goods
game could have an undesired priming effect thereby letting the answers influence the action.
A more fitting solution could be to relate the questions more to the public goods game (i.e. “I
did not trust my group”) as opposed to keeping the questions broad.
Conclusion
This study was a replication of the Rand et al. (2012) paper. It did not find the same results as
the original paper, finding a null effect. Reviewing our hypothesis which was, in short, that
time pressure condition would cooperate more when compared to the time delay condition
controlling for experience. The two conditions did not differ in their donations and experience
was shown to have no effect on cooperation. Looking at the overall reaction time versus
amount donated also did not show any effect. Even though the disobeying of the ten second
rule occurred on a large scale a controlling analysis which expanded the rule to 15 seconds,
and an analysis to see if the disobeying had a significant effect on the results showed that this
was not the case. This study therefor can claim that there are problems with the design used to
research the intuitive cooperation effect as this is another study which did not find the same

22
results as Rand et al. (2012). The papers of Tinghög et al. (2013) and Verkoeijen &
Bouwmeester (2014) also did not find the same positive results. Further research, using
different manipulations and designs is necessary to state whether or not the intuitive
cooperation effect exists, and if so, to what extent it is a strong and positive effect.

23
Reference list
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negative framing on cooperation in experiments. Quarterly Journal of Economics, 110, 1-21.
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Cubitt, R.P., Michalis, D. & Simon, G. (2011). Framing and free riding: emotional
responses and punishment in social dilemma games. Experimental Economics, 14, 254-272.
De Waal, F. (1996). Good natured, The origin of right and wrong in humans and other
animals. Cambridge, MA. Harvard University Press.
Dunn, E.W., Aknin, L.B. & Norton, M.I. (2008). Spending Money on Others
Promotes Happiness, Science, 319(5870), 1687-1688
Ghiselin, M.T. (1974). The economy of Nature and the Evolution of Sex. Berkeley,
CA. University of California Press.
Liberman, V., Samuels S. M., & Ross, L. (2004). The name of the game: predictive
power of reputations vs. situational labels in determining Prisoner’s Dilemma game moves.
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self-control benefits cooperation. Journal of Economic Psychology, 45, 213–236.
doi:10.1016/j.joep.2014.09.004
Nowak, M.A. (2006). Five rules for the evolution of cooperation. Science, 314, 1560–
1563.
Nowak, M.A. & Sigmund, K. (1992). Tit for tat in heterogeneous population. Nature,
355, 250–253.

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Nowak, MA. (2012) Evolving cooperation. Journal of Theoretical Biology, 299, 1–8.
Peysakhovich, A. & Rand, D. G. (2013). Habits of virtue: creating norms of
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from Social Science Research Network website: http://ssrn.com/abstract=2294242.
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greed. Nature, 489, 427–430.
Rand, D.G., Nowak, M.A. (2013a). Human Cooperation. Trends in Cognitive
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Rand, D. G., Greene, J. D. & Nowak, M. A. (2013b). Rand et. al. reply. Nature, 497,
E2–E3
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Nowak, M.A., Green, J.D. (2014). Social Heuristics Shape Intuitive Cooperation. Nature
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Sonnemans, J., Schram, A. & Offerman, T. (1998). Public Good Provision and Public
Bad Prevention: The Effect of Framing, Journal of Economic Behavior & Organization 34,
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Tinghög, G., Andersson, D., Bonn, C., Böttiger, H., Josephson, C., Lundgren, G.,
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are.html

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Appendix 1. The survey questions retrieved from the protocol. The participants’ survey was
translated to Dutch.
Screen 1:
In this task, you will participate in a simple decision making study. You will receive a $5
show-up fee/course credits, and then earn additional money based on your decision and the
decision of others.
You will be paid in cash immediately following the experiment.
Screen 2:
You have been randomly assigned to interact with 3 of the other people in the room. All
of you receive this same set of instructions. You cannot participate in this study more than
once.
Each person in your group is given $4 for this interaction.
You each decide how much of your $4 to keep for yourself, and how much (if any) to
contribute to the group’s common project (from 0 to 400 cents).
All money contributed to the common project is doubled, and then split evenly among the 4
group members. Thus, for every 2 cents contributed to the common project, each group
member receives 1 cent.

27
If everyone contributes all of their $4, everyone’s money will double: each of you will earn
$8. But if everyone else contributes their $4, while you keep your $4, you will earn $10, while
the others will earn only $6. That is because for every 2 cents you contribute, you get only 1
cent back. Thus you personally lose money on contributing. The other people really will make
this decision too – there is no deception in this study. Once you and the other people have
chosen how much to contribute, the interaction is over. None of you can affect each other's
payoffs other than through the single decision in this interaction.
Screen 3:
Time pressure condition: Please make your decision as quickly as possible. You must make
your decision in less than 10 seconds!
Please use the slider to choose the amount of money you wish to contribute.
Time remaining: <Timer that counts down from 10>

28
Time delay condition: Please carefully consider you decision. You must wait and think for at
least 10 seconds before making your decision!
Please use the slider to choose the amount of money you wish to contribute.Time elapsed so
far: <Timer that counts up from 0>
Screen 4 through 6:
- What level of contribution earns the highest payoff for the group as a whole?
- What level of contribution earns the highest payoff for you personally?
[These questions provide a check on the participant’s comprehension of the payoffs.]
- Please describe why you chose to contribute the amount that you did in the study.

29
Screens 7 through 27:
These screens will contain the items of the individualism/collectivism scale. The items
will be randomly presented to each participant.
Experience 1
“To what extent have you participated in studies like this one before? (i.e. where you
choose how much to keep for yourself versus contributing to benefit others)”.
[Subjects have to answer on a 5 point Likert scale with 1= Nothing like this scenario, 3 =
Somewhat like this scenario, and 5 = Exactly this scenario.]
Experience 2
“How many total experiments have you completed in exchange for credit or extra credit
in your courses?”
[Subjects have to answer this question by entering a number in a box with 0 as the
lowest response option.]

30
Experience 3
“How many total paid experiments have you done?”
[Subjects have to answer this question by entering a number in a box with 0 as the
lowest response option.]
Experience 4
“Have you done any experiments on Mechanical Turk or other online sites? If yes, how
many experiments did you do in total online?”
[Subjects first have to select yes or no in response to the first part of the question. If
they select yes, they have to answer the second part of the question by entering a
number in a box.]
Experience 5
“Although this study did not involve deception, have you previously participated in any
studies in which you were deceived about the actual purpose of the study? If yes,
estimate how many studies you have done that involved deception.”
[Subjects first have to select yes or no in response to the first part of the question. If
they select yes, they have to answer the second part of the question by entering a

31
number in a box.]
Trust-in-others
“To what extent do you feel you can trust strangers?”
Subjects have to answer on a ten-point Likert scale from “1=Very Little” to “10=Very Much”
“To what extent do you feel you can trust other people that you interact with in your daily
life?”
Subjects have to answer on a ten-point Likert scale from “1=Very Little” to “10=Very Much”
Trust 1
“Generally speaking, would you say that most people can be trusted or that you can’t be
too careful in dealing with people?”
[Subjects respond by clicking radio buttons for “Most people can’t be trusted,” “Can’t be
too careful,” or “Depends”]
Trust 2
“Do you think most people would take advantage of you if they got a chance, or would
they try to be fair?”
[Subjects respond by clicking radio buttons for “Would take advantage,” “Would try to be
fair,” or “Depends”]
Trust 3

32
“Would you say that most of the time people try to be helpful, or that they are mostly just
looking out for themselves?”
[Subjects respond by clicking radio buttons for “Try to be helpful,” “Just look out for
themselves,” or “Depends”]
Trust 4
“You can’t count on strangers anymore.”
[Subjects respond by clicking radio buttons for “More or less agree” or “More or less
disagree”]
Screens 36 to 39:
These screens will contain the four PARH items
Screen 40:
What year were you born?
Screen 41:
What is your gender?
Screen 42:
In which city and country did you grow up? If you lived in more than one place, list the
one you spent the most time in. (If the United States, please also give the state).
Screen 43:
How many other participants in the room do you know?

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