University of Amsterdam
Research Report
Social Decision Making
Predator and Prey: Fear and
Greed Motivating Groups to
Invest
Author: Jonathan Krikeb University of Amsterdam Supervisor: Prof. Dr. Carsten K. W. de Dreu University of AmsterdamJuly 14, 2014
Contents
1 Introduction 1
1.1 Social Games . . . 2
1.2 The Chicken and the Assurance game . . . 3
1.3 Greed, Fear, Predator, and Prey . . . 4
1.4 Free-Riding and Punishment . . . 5
2 Methods 7 2.1 Participants . . . 7
2.2 The Game: Predator-Prey . . . 7
2.3 Punishment . . . 8
2.4 Procedure . . . 8
2.5 Analyses . . . 9
3 Results 9
Abstract
In this study we examine the effects fear and greed have on investments in a predator-prey game that is played between two groups of three members each. In this asymmetrical game we pry apart the two motives for investment and predict predators to act more selfishly due to their greed, while the prey will unite to defend themselves out of fear. Our results suggest that fear motivates the prey towards a more aggressive investment strategy. This is also reflected in the larger number of zero-investments made among the predators. Furthermore, our results indicate that punishment can be used to reduce free-riding in predators.
Keywords: predator-prey, fear, greed, free-riding, punishment, intergroup conflict, asymmetric game
1
Introduction
Intergroup conflicts carry many dynamic factors in them and their signif-icance is very clear when studying companies competing or nations in (a cold-war) conflict (Jervis, 1978). As previous studies show, the case of in-tergroup conflict is significantly different from interpersonal conflict since it tends to escalate in severity due to the intragroup increase in greed, and fear of the out-group (Insko et al., 1990, 1993). Another confounding factor in previous studies, that is reflected in many larger conflicts, is the symmetrical aspect of the games used; a nation in middle Africa is not on the same finan-cial footing as Germany therefore any interaction between them is not ideal. Additionally, in these sort of conflicts, fear and greed are major motives that have been studied (Bornstein et al., 1996) but cannot really be separated when sticking to the symmetrical dogma. This paper will study previous research and the field and present a novel paradigm of an intergroup asym-metrical, predator-prey game, that is designed to detach the two motives of fear and greed in the decision making process.
Different games are often used in the lab in order to provide a tool to mea-sure human behaviour under controlled settings. Games such as public-goods (see: Ertan et al., 2009; Fehr & G¨achter, 2002; Nikiforakis, 2008; Rapoport et al., 1989), prisoners’ dilemma (see: Bornstein, 2003; Rapoport & Bornstein, 1987), the dictator game (see: Bernhard et al., 2006), the trust game (see: Burks et al., 2003; Seip et al., 2009), the chicken and the assurance games (see: Bornstein et al., 1996; Bornstein & Gilula, 2003; Bornstein, 2003) are established to varying degrees in the literature and provide great insight into behaviour under certain conditions. However, as Jervis (1978) observed al-ready, individual cases cannot apply to account for group dynamics, where groups can be as small as three people or as big as an entire nation. In addi-tion, while games are often symmetrical (antagonists follow the same set of rules), this is often not the case in the real world - social classes to state the obvious example. In order to bring into the lab a game that we thought could answer our questions we have taken the paradigm of the predator-prey game (De Dreu et al., 2014) and based on the idea of examining the discontinuity when converting to the group settings (Insko et al., 1990, 1993) we have also
adapted the predator-prey game into a three-against-three game. Another aspect that our design featured is punishment. We based this on previous work by Abbink et al. (2010) and Fehr & G¨achter (2002), assuming that in an asymmetrical game this will function differently as well. This new paradigm can help us answer the following questions: (i ) which is the greater motiva-tor for investment - fear or greed; and (ii ) whether a punishment system can contribute to an intergroup conflict, and if can, in which manner.
1.1
Social Games
One of the most studied games is the prisoners’ dilemma game. In game-theory, this game is used as a prime example for a Nash equilibrium; the best choice for both players is to cooperate, yet both the fear lest the other player will defect, as well as the greed and desire to maximise personal profit, lead both players to defect, which is the Nash equilibrium for this game.
The public-goods game is a related game that models the same problem in a group settings instead of the dyadic method of the prisoners’ dilemma. The participants in the public-goods game have to decide how much to contribute to a common pot (see: Barclay, 2006; Bornstein, 1992; Fehr & G¨achter, 2000, 2002; Rapoport & Bornstein, 1987; Rapoport et al., 1989). Similar to the prisoners’ dilemma, if they all cooperate and contribute then the group gains together and every individual will earn the maximum personal income. How-ever, on the individual level, not contributing guarantees the participant that he will keep his starting capital, and maybe even earn more, thus he does not have to doubt whether the remaining group members are going to cooperate by contributing. Also in this game the motives of fear and greed interact to influence the individuals decision: fear of the others failing to participate, and the will to greedily maximise personal profit by not contributing.
A third game, also playing on the level of confidence participants have in one another, is the trust game (Burks et al., 2003; de Quervain et al., 2004). In this game, one is given a sum of money that he can choose to share, or not, with the second participant of the game. The other party receives the sum, multiplied by some factor (often by 3), and then can choose whether to pay back, or not, and in matter of fact reciprocate the trust, or betray it.
The trust game separates fear and greed more neatly since the one given the starting capital will mostly be influenced by fear of the other betraying the trust, while the other player will mostly be directed by greed if he decides to betray. However, both players in this game have a motive that plays a much smaller part than in the previously mentioned games, that of guilt, and it is this motive that makes this game insufficient to study fear and greed.
The above games led us to search for a paradigm that separates the two motives of fear and greed more clearly. An aspect that we have taken from these games is that of repetition. The ”correct” way to play any of the games changes when the game is changed from a one-off to a repeated game since now there may be long-term benefits and reputation that come into the game. For instance, in the trust game, if the trustee betrayed the trust once, that may be sufficient for the trust-giver not to take a chance again and simply keep the initial capital in following rounds. Having multiple rounds in a game makes it resemble real social interaction more and will be discussed further in terms of punishment.
1.2
The Chicken and the Assurance game
In order to better split fear and greed as motives, other games have been devised with that explicit intent. Insko et al. (1990) looked at an alterna-tive version of the prisoners’ dilemma game, where the choice matrix also enables a withdrawal option that is supposed to be a safe option. This third option was meant to allow the separation of fear and greed since the fearful players will choose that option, instead of defecting. To defect, in turn, will be chosen by the greedy participants. According to Insko et al. (1990), the effect of the group immediately escalated this conflict and led to more defec-tion. Moreover, even with communication between groups, the competition remains strong as it is motivated by greed and leads to defection (unlike the results for interpersonal communication that manage to reduce fear and thus increase cooperation) (Insko et al., 1993).
Another attempt to separate the motivations of fear and greed was studied by Bornstein et al. (1996). They introduced the chicken and the assurance games.In the first, the chicken game, greed is meant to be accentuated by
having a payoff scheme that encourages offence only in case of the other team retreating. Cases of cooperation in this game earn a lower payoff for everybody, while defection is much more highly rewarded. For instance, if team A has only one contributor, team B benefits more from having two contributors, but also from having none, rather than match the individual contributor. In contrast, the assurance game is designed to have fear as its motive of investment. That is achieved by its payoff scheme that encourages competition only in case of the other team choosing to compete. The matrix guarantees the highest payoffs for both teams in all cases of cooperation, maximising it at zero contributors for both teams.
Both games are meant to keep only one of the motives available to the rational player and therefore would allow it to be measured in an experi-ment. In the assurance game the number of contributors was higher by a small percentage (5%) as compared to that observed in the chicken game, but within-group communication seemed to level the number of contributors in both games. In an interesting follow-up to this study Bornstein & Gilula (2003) added intra-, as well as intergroup communication. The results of this follow-up suggest that fear can be alleviated by communication between the groups, while greed cannot be overcome by the same method and trust can-not be established. An issue that can be raised is that both of these studies assume that in these symmetrical games indeed fear and greed are the dom-inating motives, while it could easily be imagined that in the chicken game (as the name implies), a participant would be afraid of the other participant’s potential competitiveness and decide to ”chicken-out”. Indeed, Bornstein et al. (1996) suggested in their discussion that if these games are seen as zero-sum games where participants look to maximise relative gain then both fear and greed play a part in both games.
1.3
Greed, Fear, Predator, and Prey
Insko et al. (1990) already studied fear and greed specifically as motives for investment in group games. The two studies that the article describe are both looking at the topic in a little round-about way; communication be-tween the teams (that would alleviate the fear) and an alternative prisoners’
dilemma game where the withdrawal option is a way out for those who are not interested in being competitive (thus assuming that only the very greedy will still choose to defect in the game).
It is this lack of direct evidence as well as the insufficiency of the paradigms studied by Bornstein et al. (1996) in terms of symmetry that led De Dreu et al. (2014) to come up with the predator-prey design. In their novel ex-periment, the game is permanently set as asymmetrical (see Bornstein et al. (2005) for a dynamic asymmetry). Therefore, the predators’ only motivation to invest is competition and the desire to win more, or at least take what is left of the initial endowment of the prey. In contrast, the prey’s only motive for investment is protection of its capital from the potential attacker.
This decomposition of the motives of investment was seen in their results where the prey’s investments seemed to be instinctive (quick, and following higher activation in the amygdala), whilst that of the predators was calcu-lated (took a longer time to decide and involved cortical regions such as the superior frontal gyrus that is implicated in impulse control) (De Dreu et al., 2014). In addition, the prey consistently invested more throughout the game, as the fear drove them to a defensive position.
In our study we assumed that taking this game and staging it as a group game would yield similar results, in terms of mean investment, based on the motive that drives every team. Due to the group setup of our paradigm, compared to De Dreu et al. (2014), our game will be constructed of minia-ture public-goods games within each group and these can either escalate the competition between groups (the detachment from the out-group), or as we predict, intensify the individuality based on the core motives of investment, and therefore lead to more free-riding within the predator groups (Abbink et al., 2010; Bochet et al., 2006; Bornstein, 1992, 2003; Decker et al., 2003; Rapoport & Bornstein, 1987).
1.4
Free-Riding and Punishment
Following the ideas above of free-riding and repeated interaction, we would like to introduce here the topic of altruistic punishment, as it is a tool that has been widely used, in the lab and outside it, to maintain cooperation
(Abbink et al., 2010; Barclay, 2006; Cubitt et al., 2010; Decker et al., 2003; Egas & Riedl, 2008; Ertan et al., 2009; Fehr & G¨achter, 2000; O’Gorman et al., 2009; Van Lange et al., 2007; Seip et al., 2009; Sutter et al., 2010). As we asserted earlier, we predict that the greed within the predator groups will lead them to free-ride; invest less than their fellows, or nothing, in order to maximise personal gain - if the group loses they keep their initial endowment, and if the group wins they earn something in addition to it. Underlying our assumption, that contradicts reduced free-riding in intergroup competition (see: Bornstein, 2003), is the asymmetry of our game.
To test that the free-riding in our game is motivated as it has been pre-viously studied in public-goods games, we introduce a punishment system that is often used in experiments with the belief that it is a mechanism for the prevention of the phenomenon. The effects of altruistic punishment have been studied in different contexts; for instance: at what time of the experi-ment is it introduced to the participants (Fehr & G¨achter, 2002), or the size of it (Egas & Riedl, 2008). In addition, there are different reasons that seem to motivate people to invest in order to punish, but anger seems to be main among them (Seip et al., 2009). The overall goal of punishing altruistically is to maintain cooperation within the group, and the efficiency of this treat-ment highly depends on reputation building (O’Gorman et al., 2009; Egas & Riedl, 2008; Decker et al., 2003). If free-riding is motivated by greed then it should be exacerbated among the predators and also be punished more strictly which in turn will lead to its reduction.
Therefore, for this study we hypothesised the follows: based on the results of De Dreu et al. (2014), the prey group, which is the one that stands to lose its capital, will invest more in order to protect itself from the predator group, whose investment motivation is greed. Moreover, we assumed that the greedy group will not only have a less aggressive behaviour, but will also have more free-riders in it. Finally, we hypothesised that the predators will be more prone to react to punishment, and this will show in increased investment as well as reduction in the number of free-riders.
2
Methods
2.1
Participants
Participants were recruited through the University of Amsterdam’s recruit-ment system (http://lab.uva.nl). We overbooked for each session so as to ensure sufficient group-members in every session. We had a total of 144 par-ticipants eventually and those that could not participate received only the participation fee (e10). The participants were comprised of 38 males (26%) and 106 females (74%) with ages ranging between 18 and 61 (mean 23.5). Participants received, in addition to the participation fee, a sum that was averaged based on four random rounds of the ten-round game. This addi-tional sum could not surpass the participation fee itself (thus in total capping profits per participant at e20. Participants’ mean payment was e13.6).
2.2
The Game: Predator-Prey
In this asymmetrical game, one group’s worst outcome is not to gain (preda-tor group), while the other group can at best not-lose (prey group). The de-sign is based on a previous study by De Dreu et al. (2014). The players invest individually, without any communication with their fellow group-members, into a common pot (predator investment: 0 ≤ α ≤ E; α1+ α2+ α3 = Ipred;
prey investment: 0 ≤ β ≤ E; β1+ β2+ β3 = Iprey). The group that invests
more, wins the round, with a tie counting as a win for the prey. For the predators, winning the round means keeping what is left of their endowment and in addition, taking all that is left of the starting-capital of the prey-group after their investment (Ipred > Iprey ⇒ E − αx+ ((E × 3 − Iprey) ÷ 3)). A
win for the prey means that each of them gets to keep what they have not invested into the common pot (Iprey > Ipred ⇒ E − βx). In that scenario,
also the predator-group get to keep their uninvested money for their eventual income of the round (Iprey > Ipred⇒ E − αx).
2.3
Punishment
In addition to the standard game-play, we introduce a punishment treatment. The punishment was set at a ratio of 1:3; for every point invested, three are deducted from the punished member. Punishment could be dealt only to members of the same team. This was based on the studies by Fehr & G¨achter (2002), Fehr & Fischbacher (2004), Egas & Riedl (2008), and Abbink et al. (2010), of altruistic-punishment that showed the effectiveness of it in increasing investment and inhibiting free-riding.
2.4
Procedure
Participants arrived in the lab and were immediately assigned to a cubicle by one of the experimenters. Their assignment into groups was completely at random. Each group, predator or prey, was comprised of three partici-pants. Since we had a within-subjects treatment then in half of the sessions we started with the treatment, and in the other half without. After signing the informed-consent, subjects were given to read the instructions on-screen and then a small set of exercises to confirm their understanding of the rules. Until the exercises were clear to all the members, the game was not initi-ated. During the game, the subjects were given investment forms in every round and asked to invest between 0 and 20 Experimental-Euros (EE, 20 being the initial endowment. EEs were later converted to Euros based on role in the game and the e20 limitation). The experimenters then collected and calculated the results of every round using a Google-Drive spreadsheet. Participants were then given a sheet with the results and asked to make the next investment.
In the no-treatment condition, the next investment was simply the next round. In the treatment condition the next investment involved the option to punish fellow group members. Participants were allocated an additional 10EE for the punishment, of which they could use up to 5EE to deduct from each player (thus if one player is punished maximally by his two group members he will be lose 30EE; that is equivalent to the maximum he can accrue if he invests nothing during that round). This second investment form included a report of the investments made by both groups, and in addition,
Role Predator µ(SD) Prey µ(SD) FRole FTreat FRxT
Treatment w P w/o P w P w/o P
Investment 25(8.2) 21.7(9.5) 31(5.9) 29.5(7.5) 18.4*** 2.2 0.3
# 0-investors 0.4(0.67) 0.68(0.87) 0.01(0.09) 0.03(0.2) 108.7*** 8.9** 7**
*** - p ≤ 0.001, ** - p ≤ 0.01, * - p ≤ 0.05
Table 1: Means and standard deviations of investment and the number of free-riders divided into role and treatment. F values are from the ANOVA tests.
the investments made by the participants’ two fellow group-members. This form was also collected by the experimenter and a final calculation for income for the round was made and given to the participants. Both conditions of the game were run for five rounds thus making the game ten rounds in total. After the game was complete, participants were given a questionnaire to fill that was meant to measure their subjective motivations during the game. Eventually, the participants were debriefed and sent back to their daily business. (For all the forms see the supplementary material)
2.5
Analyses
The data was analysed using RStudio. It was first extracted from the sepa-rate spreadsheets collected during the experiment into a database file. Mul-tivariate analysis of variance (MANOVA) and analysis of variance (ANOVA) tests were run the investment data with investments, mean investments, and number of free-riders being the dependent variables. For the ANOVA to test the main hypothesis we averaged over five rounds of the game; with and without treatment. For the sake of keeping a standardised valuation, we defined free-riding as zero-contribution throughout the analysis. for the effect of punishment we used a test for proportions of populations based on a χ-squared test (R command: prop.test).
3
Results
In order to use the data of 24 sessions as belonging to two independent mea-surements, we ran a MANOVA to control for the within-subject punishment
Figure 1: Boxplot of mean investments based on role and treatment.
treatment that we administered. For this analysis we split the investments, being the dependent variables, into roles, and had the treatment as the in-dependent variable. The results from the MANOVA showed no significance (p > 0.1) so we proceeded to test our hypotheses treating the data as 24 sessions of five rounds with treatment and 24 sessions of five rounds without treatment.
To test the main hypothesis, an ANOVA test showed high significance (p < 0.001, see table 1) when examining the investments made by prey as compared to predators. For this analysis, again, the investment was the dependent variable.
Our second hypothesis concerned the issue of free-riding. We first looked simply at the number of free-riders in the prey versus that in the predator group. Counting the overall number of zero-investments already clearly in-dicated a difference between predator and prey; 130 cases of zero-investment in the predators (out of 720, 18% of investments) in comparison to 4 in the prey (0.5%). A χ-squared-test for proportions of populations on the zero-investments indicates a clear effect for role (χ = 128.6, df = 1, p < 0.01, see figure 2).
Figure 2: Number of zero-investment events. Blue - with punishment in effect. Red - Pun-ishment not in effect.
Testing the effect of the punishment treatment overall showed no significance. However, since our design was a 2X2 de-sign, we ran an ANOVA with investment as an independent variable and role (preda-tor or prey) as well as treatment (with or without punishment) being the dependent ones. This test also failed to find significance nor interaction between the two parameters. Only when adding the rounds to the analy-sis did a treatment effect emerge (p < 0.01, see table 1). However, no interaction effects emerged as significant still.
This led us to test the effect of punish-ment on free-riding specifically, which was our third hypothesis. By comparing the number of zero-investment cases when punishment is in effect to when it is not, we observed a reduction of 70% in free-riding among the predators (82 without punishment compared to 48). We also saw a reduction in free-riding among the prey of 200%; 3 compared to 1. However, that is not of much interest due to the insignificance of the phenomenon. See figure 2). A χ-squared-test for proportions on the predators’ reduction in zero-investors due to punishment showed a significant effect (χ = 10.2, df = 1, p < 0.01).
When running a similar ANOVA for the number of free-riders over rounds, as has been performed for investments, we found a significant effect for role (p < 0.001, see table 1), as well as significance for treatment, round, and the interaction between role and treatment (p<0.01, see table 1 and figure 3). The interaction between role and round shows weaker effect (p < 0.05).
4
Discussion
In this study we have set out to examine the roles of greed and fear as motives for investment in intergroup conflict situations. We have designed and used a new paradigm that involves group dynamics, therefore establishing a
minia-Figure 3: Mean investments over rounds separated into punishment, no-punishment, predator, and prey.
ture public goods game within every team, that would hopefully replicate the results seen by De Dreu et al. (2014) in their interpersonal predator-prey game. In addition, we looked for the effect that punishment will have in such an asymmetrical game and hypothesised that it will not influence both teams identically - namely, the punishment will be used more and its effect visible among the predators. Our results show that indeed, as we predicted from the interpersonal version of the game, the prey group is more aggressive in their investments in an attempt to protect their capital. This we can assume to be due to the influence of fear on the players (and in addition, it affirms that despite the complexity of the game, the participants have indeed grasped the rules).
A further demonstration of the influence of fear on investment is the frequency of free-riding. As the results demonstrate, the occurrence of zero-investment events among the prey is virtually non-existent. This result, as compared to the frequency of free-riding among the predators, is quite revealing. We can further speculate that the predators are more willing to sacrifice their fellow group-members, and not simply pacifists, based on the increase in mean investment value that was observed when punishment is in
Figure 4: Mean number of zero-investors (AKA free-riders) over rounds split according to role and treatment.
effect (to be verified using future analysis of the questionnaire data).
Concerning the treatment that has been implemented, we could initially not discern much. However, a more elaborate analysis showed us that indeed the punishment has an effect. As can be seen in figure 1 and table 1, the punishment influenced the variance in investments among both the predators and the prey. This can also be seen in figure 3. Figure 4 enables us to explain both plots since we can see the influence punishment has on the number of zero-contributors in the team. This effect can only work in the predator groups for the obvious reason that free-riding is not a problem that the prey suffer from (even though what little exists without punishment is also affected by its introduction). While punishment does seem to reduce the variance in the prey’s investments as seen in figure 1, the mean remains almost the same and among the prey overall there is not even an end-game effect (see figure 3). Our results therefore suggest, in agreement with those of Fehr & G¨achter (2000), that free-riding is heavily suppressed by punishment. What our study adds to the previous findings is that the punishment seems to work also when there is an intergroup conflict and not only an interpersonal one. Additionally, this punishment is useful only to treat the greed motive, as it
adds fear into the predators’ calculations, while fear cannot be added to the already fearful group, the prey.
In conclusion, we have managed to observe that even without coordina-tion, an intergroup predator-prey game leads to more aggressive investment behaviour among the fearful prey groups, and more free-riding among the greedy predator groups. This supports the results obtained in the interper-sonal scenario of this game (De Dreu et al., 2014) and leads us to believe that fear is a stronger motivator for investment.
Acknowledgements
First, I would like to thank Prof. Carsten De Dreu, my supervisor, for all his guidance, support, as well as the budget. In addition, I am thankful to my partner in this project, Simon Hadlich, for his collaboration. Finally, I would like to thank Kyra Lubbers for her help with translation and in data-collection, and also Michael Giffin for helping in data-collection.
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Jervis, R. (1978). Cooperation Under the Security Dilemma. World Politics, 30 (2), 167–214.
Nikiforakis, N. (2008, February). Punishment and counter-punishment in public good games: Can we really govern ourselves? Jour-nal of Public Economics, 92 (1-2), 91–112. Retrieved from http://linkinghub.elsevier.com/retrieve/pii/S0047272707000643 doi: 10.1016/j.jpubeco.2007.04.008
O’Gorman, R., Henrich, J., & Van Vugt, M. (2009, January). Con-straining free riding in public goods games: designated solitary punishers can sustain human cooperation. Proceedings of the Royal Society. Series B, Biological Sciences, 276 (1655), 323–9. Retrieved from http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2674351 doi: 10.1098/rspb.2008.1082
Rapoport, A., & Bornstein, G. (1987). Intergroup com-petition for the provision of binary public goods. Psy-chological Review , 94 (3), 291–299. Retrieved from http://doi.apa.org/getdoi.cfm?doi=10.1037/0033-295X.94.3.291 doi: 10.1037//0033-295X.94.3.291
Rapoport, A., Bornstein, G., & Erev, I. (1989). Intergroup competition for public goods: Effects of unequal resources and relative group size. Journal
of Personality and Social Psychology, 56 (5), 748–756. Retrieved from http://doi.apa.org/getdoi.cfm?doi=10.1037/0022-3514.56.5.748 doi: 10.1037//0022-3514.56.5.748
Seip, E. C., van Dijk, W. W., & Rotteveel, M. (2009, June). On hotheads and Dirty Harries: the primacy of anger in altruistic punishment. An-nals of the New York Academy of Sciences, 1167 , 190–6. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/19580565 doi: 10.1111/j.1749-6632.2009.04503.x
Sutter, M., Haigner, S. D., & Kocher, M. G. (2010, October). Choos-ing the Carrot or the Stick? Endogenous Institutional Choice in Social Dilemma Situations. Review of Economic Studies, 77 (4), 1540–1566. doi: 10.1111/j.1467-937X.2010.00608.x
Van Lange, P. A. M., De Cremer, D., Van Dijk, E., & Van Vugt, M. (2007). Self-Interest and Beyond: Basic Principles of Social Interaction. In A. W. Kruglanski & E. T. Higgings (Eds.), Social psychology: Handbook of basic principles (pp. 540–561). New York, NY: Guilford.
Appendix
3 3
Economic Experiments on Social Behaviour
In deze studie wordt u gevraagd investeringsbeslissingen te nemen. U speelt samen met 2
groepsgenoten tegen een andere groep die ook uit 3 personen bestaat. Afhankelijk van uw investering, en de investeringen van alle andere spelers, kunt u een extra geldbedrag verdienen dat zal worden uitbetaald bovenop de vergoeding die u krijgt voor deelname. Na een paar weken, als de gehele studie is afgerond, zult u dit gehele bedrag op uw bankrekening ontvangen. Deze studie is gefinancierd door de Universiteit van Amsterdam.
De investeringen die u doet zijn en blijven anoniem. De andere spelers die betrokken zijn bij het maken van de beslissingen zullen uw identiteit niet te weten komen. U zult ook de identiteit van de andere spelers niet te weten komen.
Op de volgende pagina’s worden de investeringsbeslissingen in detail uitgelegd. Vervolgens zullen er een aantal oefenvragen gesteld worden om er zeker van te zijn dat u de verschillende situaties begrijpt. Het is belangrijk dat u de gevolgen van uw investeringen goed begrijpt omdat deze niet alleen
beïnvloeden wat u gedurende het spel verdient, maar ook wat de andere spelers verdienen. Mocht er iets onduidelijk zijn, stel dan gerust uw vraag aan de experimentleider.
Investeringsbeslissingen en uitbetaling.
De studie is opgedeeld in 2 blokken van 5 rondes. De blokken zijn grotendeels gelijk maar, in één van de blokken neemt u extra beslissingen. Voor de uitbetaling aan het einde van de studie zullen uit blok 1 en uit blok 2 allebij twee willekeurige rondes worden geselecteerd. Vervolgens zullen we berekenen wat u deze rondes heeft verdiend en wat de andere 5 deelnemers hebben verdiend die betrokken waren bij de beslissingen. Dit bepaalt hoeveel geld u uiteindelijk extra verdient. U kunt maximaal €10,- extra verdienen. Het bedrag dat u extra verdient wordt bij uw deelnamevergoeding opgeteld en privé aan u uitbetaald.
3 3
Economic Experiments on Social Behaviour
In this study you will be asked to make investment decision. You will play with 2 other group members against another group that also consists of 3 members. Depending on your investments, and those of the other players, you can earn extra money in addition to the participation fee. You will be paid in a few weeks once the study is finished. This research is financed by the University of Amsterdam.
The investments that you will make shall remain anonymous. The other players will not be informed as to your identity. You will also not be informed about theirs.
On the following pages the investment decisions shall be laid out in detail. Following the instructions, a few exercises will be given to make certain that you understand the different decisions and their consequences. It is important that you understand what the consequences of your decisions are since they will influence both your earnings and those of the other participants. If anything is unclear, please do not hesitate to ask the experimenter.
Investment decisions and payoffs
The experiment is comprised of 2 blocks of 5 rounds each. You will receive instructions for each block separately. Eventually, four random rounds, two from each block, will be chosen to calculate your additional earnings from the game. We will calculate what your earnings, and those of the other 5 participants, were based on your decisions in these rounds. This will decide how much you will earn, up to €9, in addition to the participation fee. The other participants will not know how much you earned.
A2: Instructions, examples, and comprehension questions for predator without punishment, Dutch and English
4 4
Individuele beslissingen
U krijgt aan het begin van elke ronde 20 Experiment-Euros (EE) Startkapitaal per persoon. U kunt elke ronde tussen de 0 en 20EE investeren (alleen ronde bedragen). Hetzelfde geldt vooruw twee groepsgenoten en voor de leden van de andere groep.
Als u en uw groepsgenoten evenveel of minder investeren dan de andere groep, dan houdt u het restant van de 20 EE. Bijvoorbeeld, u investeert 4 en uw groepsgenoten ook (dus 12EE in totaal), en de andere groep investeert in totaal 15EE, dan verdient u 20 – 4 = 16EE (en je groepsgenoten ook) en de andere groep vertdient 60 – 15 = 45EE.
Als u en uw groepsgenoten meer investeren dan de andere groep dan houdt u wat over is van uw 20 EE en krijgen jullie alles dat over is van het startkapitaal van de andere groep, wat eerlijk verdeeld wordt over u en uw groepsgenoten. Dus als jullie allemaal 5EE investeren (in totaal 15) en de andere groep investeert 12 dan verdienen jullie per persoon 20 – 5 = 15EE + van de andere groep: 60 – 12 = 48EE, dus in totaal voor uzelf 15 + (48 / 3 =) 16 = 31EE. In dit voorbeeld verdient de andere groep niets.
Gebruik voor het maken van uw beslissingen het formulier dat voor u klaarligt op tafel. Gebruik een nieuw formulier voor elke ronde en overhandig het aan de experimentleider die het komt ophalen. Na elke ronde maakt de experimentleider bekend hoe veel EE’s de beide groepen in totaal hebben geïnvesteerd.
Uw uiteindelijke inkomsten worden bepaalt door wat u over heeft aan het einde van de ronde en wat u krijgt van de andere groep.
De onderstaande tabel geeft enkele voorbeelden van investeringsbeslissingen:
8
7 7
Samenvatting van de individuele beslissingen
1. Voor elke beslissing zijn u en uw 2 groepsgenoten die zich in de naburige kamers bevinden gekoppeld aan een andere soortgelijke groep van 3 personen.
2. Investeringsbeslissingen zijn anoniem en kunnen een groot extra geldbedrag opleveren.
3. U behoudt wat over is van uw startkapitaal als uw groep evenveel of minder investeert dan de andere groep. Daarbovenop kunt u wat over is van het startkapitaal van de andere groep verkrijgen als uw groep meer investeert.
4. Aan het einde van de studie selecteren we willekeurig een aantal van uw investeringsbeslissingen en berekenen we uw inkomsten en die van uw groepsgenoten. Op basis hiervan wordt het bedrag bepaald dat u extra heeft verdiend en dit bedrag zal worden opgeteld bij je deelnamevergoeding.
4 4
Individual decision
You will receive a starting capital of 20 Experiment-Euros (EE) at the beginning of each round. You can then choose how much you would like to invest, between 0 and 20 EE (only in integers). The same applies to the other two members of your group, and to the other group. If you as a group invest the same or less than the other group, then you get to keep whatever is left of your starting capital of 20EE. For instance: if you invest 4 and so do your two fellow group members (therefore totalling 12EE), and the other group invests 15EE in total, then your earnings are 20 – 4 = 16EE (and the same for your group members), and the other group’s earnings are 60 – 15 = 45EE.
If you as a group invest more than the other group then you get to keep whatever is left of your 20EE starting capital. In addition, each member of your group will receive one third of what is left-over from the other group’s investment in that round. Therefore, if you invest 5EE each (total of 15), and the other group invests 12EE, then your personal earnings are 20 – 5 = 15EE + from the other group: 60 – 12 = 48EE, totalling for yourself 15 + (48 / 3 =) 16 = 31EE. In this example the other group ends up earning nothing in this round.
For your decisions use the form placed on your table. Please use a new form for every round and hand it to the experimenter who will come to collect it. After every round the experimenter will inform you how much each group has invested in that round.
What you have left at the end of every round will decide your eventual takings from this game. The table below contains some examples.
Summary of individual decision
1. For every decision you are coupled to 2 other group members in the neighbouring cubicles and your group is paired with a similar 3 person group.
2. Your investments are anonymous and can result in extra earnings for you. 3. You will keep what you have left of your starting capital if your group invests the same or less
than the other group. If you invest more than the other group, then you will receive what is left-over of the starting capital of the other group in addition to what you have left left-over yourself. 4. At the end of the study we will choose a few random rounds of the game and based on the
decisions you and the other participants made in these rounds we will calculate your earnings. These will be added to the basic participation fee.
Proefpersoonnummer _____
Oefenvragen
1. Aan het begin van de ronde krijgt elke speler 20EE. U investeert 5EE, uw groepsgenoten
investeren samen nog 12EE en de andere groep
investeert in totaal 9EE. Met deze informatie geef een antwoord voor de volgende vragen:
U hield ______ over na de investeringsronde (geef een getal tussen de 0 en 20).
Uw groep kreeg in totaal _____ van de andere groep (geef een getal tussen de 0 en 60). Uw uiteindelijke persoonlijke inkomsten zijn dus _____ (geef een getal tussen 0 en 50). Inkomsten van de andere groep zijn _____ (geef een getal tussen 0 en 60)
2. Aan het begin van de ronde krijgt elke speler 20EE. U investeert 2EE, uw groepsgenoten
investeren samen nog 2EE, en de andere groep investeert in totaal 15EE. Met deze informatie geef een antwoord voor de volgende vragen:
U hield ______ over na de investeringsronde (geef een getal tussen de 0 en 20).
Uw groep kreeg in totaal _____ van de andere groep (geef een getal tussen de 0 en 60). Uw uiteindelijke persoonlijke inkomsten zijn dus _____ (geef een getal tussen 0 en 50). Inkomsten van de andere groep zijn _____ (geef een getal tussen 0 en 60)
Participant number ____
Exercises
1. At the beginning of the round, each participant receives 20EE. You invest
5EE, your group members invest 12EE together, and the other group invests 9EE in total. Based on this information, please calculate the following:
You had ____ left after your investment (fill-in a number between 0 and
20).
Your group received in total ____ (fill-in a number between 0 and 60)
from the other group.
Your final personal income is _____ (fill-in a number between 0 and 50).
The other group’s income is _____ (fill-in a number between 0 and 60). 2. At the beginning of the round, each participant receives 20EE. You invest
2EE, your group members invest 2EE in total, and the other group invests 15EE in total. Based on this information, please calculate the following:
You had ____ (fill-in a number between 0 and 20) left after your
investment.
Your group received in total ____ (fill-in a number between 0 and 60)
from the other group.
Your final personal income is _____ (fill-in a number between 0 and 50).
A3: Instructions, examples, and comprehension questions for predator with punishment, Dutch and English
4 4
Individuele beslissingen
U krijgt aan het begin van elke ronde 20 Experiment-Euros (EE) Startkapitaal per persoon. U kunt elke ronde tussen de 0 en 20 EE investeren (alleen ronde bedragen). Hetzelfde geldt voor uw twee groepsgenoten en voor de leden van de andere groep.
Als u en uw groepsgenoten evenveel of minder investeren dan de andere groep, dan houdt u het restant van de 20 EE. Bijvoorbeeld, u investeert 4 en uw groepsgenoten ook (dus 12 in totaal), en de andere groep investeert in totaal 15EE, dan verdient u 20 – 4 = 16EE (en je groepsgenoten ook) en de andere groep vertdient 60 – 15 = 45EE.
Als u en uw groepsgenoten meer investeren dan de andere groep, dan houdt u wat over is van uw 20 EE en krijgen jullie alles dat over is van het startkapitaal van de andere groep, wat eerlijk verdeeld wordt over u en uw groepsgenoten. Dus, als jullie allemaal 5EE investeren (in totaal 15) en de andere groep investeert 12 dan verdienen jullie per persoon 20 – 5 = 15EE + van de andere groep: 60 – 12 = 48EE, dus in totaal voor uzelf 15 + (48 / 3 =) 16 = 31EE. In dit voorbeeld verdient de andere groep niets. Gebruik voor het maken van uw beslissingen het formulier dat voor u klaarligt op tafel. Gebruik een nieuw formulier voor elke ronde en overhandig het aan de experimentleider die het komt ophalen. Na elke ronde maakt de experimentleider bekend hoe veel EE’s de beide groepen in totaal hebben geïnvesteerd.
Na de investeringsronde maakt de experimentleider de winnende groep bekend en krijgt u te horen welke investeringen uw groepsgenoten hebben gemaakt. U krijgt nu een bedrag van 10EE dat u mag gebruiken om de inkomsten van de andere twee groepsgenoten te verminderen. Voor elke speler mag u tussen de 0 en 5EE spenderen, of voor beide spelers 0 als u hun inkomsten niet wil verminderen. Voor elke 1EE die u gebruikt wordt er 3EE van de inkomsten van de groepsgenoot afgetrokken. Wat van deze 10EE nog bestaat wordt toegevoegd aan uw inkomsten.
Bijvoorbeeld, u heeft 9EE over van uw startkapitaal, speler A heeft 10 over en speler B heeft 12 over. Als u 2 EE investeert in speler A en 1 in speler B dan houdt u (10 – 2 – 1 =) 7 + 9 = 16EE over. Speler A houdt dan 10 – (2 x 3 =) 6 = 4EE over en speler B houdt 12 – (1 x 3 =) 3 = 9EE over. Natuurlijk moet u er rekening mee houden dat het mogelijk is dat de andere groepsgenoten EEs van elkaars inkomsten of van uw inkomsten aftrekken dus ziet u dat niet in de rekeningen boven. Het is mogelijk om een ronde met een negatief bedrag aan inkomsten af te sluiten. Voor het doorgeven van deze beslissingen ligt een apart formulier klaar op tafel. Gebruik elke ronde een nieuw formulier om uw beslissingen door te geven.
Uw uiteindelijke inkomsten worden bepaalt door wat u over heeft aan het einde van de ronde en wat u krijgt van de andere groep.
De onderstaande tabel geeft een aantal voorbeelden van investeringsbeslisisngen: Proefpersoonnummer _____
Oefenvragen
3
7 7
Samenvatting van individuele beslissingen
1. Voor elke beslissing zijn u en uw 2 groepsgenoten die zich in de naburige kamers bevinden gekoppeld aan een andere soortgelijke groep van 3 personen.
2. Investeringsbeslissingen zijn anoniem en kunnen een groot extra geldbedrag opleveren.
3. U behoudt wat over is van uw startkapitaal als uw groep evenveel of minder investeert dan de andere groep. Daarbovenop kunt u het restant van het startkapitaal van de andere groep verkrijgen als jullie meer investeren.
4. Na investering kunt u tussen de 0 en 5EE investeren om te verlagen de inkomsten van uw groepsgenoten. Uw groepsgenoten kunnen ook uw imkomsten verlagen. Elke EE dat u gebruikt verlagt 3EE van de inkomsten van uw groepsgenoot, en elke EE dat u spaart gaat naar uw eigen inkomsten.
5. Aan het einde van de studie selecteren we willekeurig een aantal van uw investeringsbeslissingen en berekenen we uw inkomsten en die van uw groepsgenoten. Op basis hiervan wordt het bedrag bepaald dat u extra heeft verdiend en dit bedrag zal worden opgeteld bij uw deelnamevergoeding.
4 4
Individual decision
You will receive a starting capital of 20 Experiment-Euros (EE) at the beginning of each round. You can then choose how much you would like to invest, between 0 and 20 EE (only in integers). The same applies to the other two members of your group, and to the other group. If you as a group invest the same or less than the other group, then you get to keep whatever is left of your starting capital of 20EE. For instance: if you invest 4 and so do your two fellow group members (therefore totalling 12EE), and the other group invests 15EE in total, then your earnings are 20 – 4 = 16EE (and the same for your group members), and the other group’s earnings are 60 – 15 = 45EE.
If you as a group invest more than the other group then you get to keep whatever is left of your 20EE starting capital. In addition, each member of your group will receive one third of what is left-over from the other group’s investment in that round. Therefore, if you invest 5EE each (total of 15), and the other group invests 12EE, then your personal earnings are 20 – 5 = 15EE + from the other group: 60 – 12 = 48EE, totalling for yourself 15 + (48 / 3 =) 16 = 31EE. In this example the other group ends up earning nothing in this round.
For your decisions use the form placed on your table. Please use a new form for every round and hand it to the experimenter who will come to collect it.
After the investments, the experimenter will inform you which group has won and how much your other two group members have invested in this round. You will then receive an additional 10EE that you can use to reduce the earnings of your two group members. You can spend between 0 and 5EE on each of them, or spend 0 and thus reduce nothing from either. For every 1EE spent, you reduce the earnings of the targeted group member by 3EE. Whatever you do not use of the 10EE gets added to your earnings for the round.
For example: you have 9EE left-over of your starting capital, player A has 10EE, and player B has 12EE. Each of you receives an additional 10EE. If you spend 2EE on player A and 1EE on player B, then you keep (10 – 2 – 1=) 7 + 9 = 16EE. Player A then has 10 – (2 x 3 =) 6 = 4EE left and player B has 12 – (1 x 3 =) 3 = 9EE left. These calculations do not include of course what they may have chosen to deduct from each other, nor what they have chosen to deduct from your earnings. It is possible to finish a round with negative earnings. You will receive a separate form for these decisions. Please use a new form every round.
Your earnings at the end of each round will decide your eventual earnings from this game. The table below contains some examples.
Summary of individual decision
1. You are coupled to 2 other group members in the neighbouring cubicles and your group is paired with a similar 3 person group.
2. Your investments are anonymous and can result in extra earnings for you. 3. You will keep what you have left of your starting capital if your group invests the same or less
than the other group. If you invest more than the other group, then you will receive what is left-over of the starting capital of the other group in addition to what you have left left-over yourself. 4. After the investment, you can spend up to 5EE on reducing the earnings of your fellow group members. Your group members can also spend EE to reduce your earnings. Each EE spent reduces the earnings of the targeted player by 3EE, and each EE saved is added to your earnings. 5. At the end of the study we will choose a few random rounds of the game and based on the
decisions you and the other participants made in these rounds we will calculate your earnings. These will be added to the basic participation fee.
Proefpersoonnummer _____
Oefenvragen
1. Aan het begin van de ronde krijgt elke speler 20EE. U investeert 4EE, uw groepsgenoten
investeren samen nog 15EE, de andere groep investeert 9EE. Met deze informatie geef een antwoord voor de volgende vragen:
U hield ______ over na de investeringsronde (geef een getal tussen de 0 en 20).
Uw groep kreeg in totaal _____ van de andere groep (geef een getal tussen de 0 en 60). Uw uiteindelijke persoonlijke inkomsten zijn dus _____ (geef een getal tussen 0 en 50).
Inkomsten van de andere groep zijn _____ (geef een getal tussen 0 en 60)
Nu krijgt elke speler nog 10EE. U investeert 1EE in speler A en 0EE in B, ze hadden respectievelijk 27 en 32EE. Uw inkomsten zijn door Speler A en/of B met 3EE verlaagd. Met deze informatie geef een antwoord voor de volgende vragen:
Uw inkomsten na de investeringsronde waren _____ (geef een getal tussen de 0 en 50).
Van de 10 EE die u kon gebruiken om te investeren in speler A en speler B heeft u nog _____ over (geef een getal tussen de 0 en 10).
Uw groepsgenoten hebben uw inkomsten met ____ verlaagd (geef een getal tussen de 0 en 30).
Participant number ____
Exercises
1. At the beginning of the round, each player receives 20EE. You invest 4EE, your group invests an additional 15EE, and the other group invests 9EE. Based on this information, please calculate the following:
You had ____ left after your investment (fill-in a number between 0 and 20).
Your group received in total ____ from the other group (fill-in a number between 0 and 60). Your final personal income is _____ (fill-in a number between 0 and 50).
The other group’s income is _____ (fill-in a number between 0 and 60).
Now, each player receives an additional 10EE. You invest 1EE to reduce from player A and
0EE to reduce from B. They had 27 and 32 EE left-over after the investment, respectively.
Your earnings have been reduced by 3EE by player A and/or B. Based on this information, please calculate the following:
Your earnings after the investment round were ____ (fill-in a number between 0 and 50). Of the additional 10EE, after spending on reducing from A and B you have ____ (fill-in a number between 0 and 10) left.
Your group has reduced your earnings by ____ (fill-in a number between 0 and 30).
A4: Instructions, examples, and comprehension questions for prey with-out punishment, Dutch and English
4 4
Individuele beslissingen
U krijgt aan het begin van elke ronde 20 Experiment-Euros (EE) Startkapitaal per persoon. U kunt elke ronde tussen de 0 en 20EE te investeren (alleen ronde bedragen). Hetzelfde geldt voor uw twee groepsgenoten en voor de leden van de andere groep.
Als u en uw groepsgenoten minder investeren dan de andere groep, dan krijgt de andere groep het restant van uw 20EE startkapitaal (plus het restant van de startkapitalen van uw twee groepsgenoten). Bijvoorbeeld, u investeert 4 en uw groepsgenoten ook (dus 12 in totaal) en de leden van de andere groep investeren ieder 5 (dus 15 in totaal), dan gaat de 16EE die over is uit uw startkapitaal (en de 32EE van uw groepsgenoten) in zijn geheel naar de andere groep. Als een gevolg hiervan verdient de andere groep 48EE + (60 – 15 =) 45EE = 93EE.
Als u en uw groepsgenoten even veel of meer investeren dan de andere groep, dan behoudt u wat over is van uw 20EE startkapitaal (dit geldt ook voor uw groepsgenoten); hetzelfde geldt voor de andere groep. Dus, als jullie allemaal 5 investeren (in totaal 15) en de spelers van de andere groep investeren ieder 4 (in totaal 12), dan verdient u 20 – 5 = 15EE.
Gebruik voor het maken van uw beslissingen het formulier dat voor u klaarligt op tafel. Gebruik een nieuw formulier voor elke ronde en overhandig het aan de experimentleider die het komt ophalen. Na elke ronde maakt de experimentleider bekend hoe veel EE’s de beide groepen in totaal hebben geïnvesteerd.
Uw uiteindelijke inkomsten worden bepaalt door wat u over heeft aan het einde van de ronde.
De onderstaande tabel geeft enkele voorbeelden van investeringsbeslissingen:
8
7 7
Samenvatting van de individuele beslissingen
1. Voor elke beslissing zijn u en uw 2 groepsgenoten die zich in de naburige kamers bevinden gekoppeld aan een andere soortgelijke groep van 3 personen.
2. Investeringsbeslissingen zijn anoniem en kunnen een groot extra geldbedrag opleveren.
3. U behoudt wat over is van uw startkapitaal als uw groep evenveel of meer investeert dan de andere groep. Als jullie minder investeren dan de andere groep dan krijgt de andere groep wat over is van jullie startkapitaal en verdient u niets.
4. Aan het einde van de studie selecteren we willekeurig een aantal van uw investeringsbeslissingen en berekenen we uw inkomsten en die van uw groepsgenoten. Op basis hiervan wordt het bedrag bepaald dat u extra hebt verdiend en dit bedrag zal worden opgeteld bij uw deelnamevergoeding.
4 4
Individual decision
You will receive a starting capital of 20 Experiment-Euros (EE) at the beginning of each round. You can then choose how much you would like to invest, between 0 and 20 EE (only in integers). The same applies to the other two members of your group, and to the other group. If you as a group invest less than the other group, then the other group will receive whatever is left-over from your 20 EE starting capital (as well as what is left of the starting capital of your other 2 group members). For instance: if you invest 4EE, and your group invests the same (therefore totalling 12EE), and the other group invests 5EE each (totaling 15), then your leftover 16EE (and 32EE of your group members) will transfer to the other group. The other group will therefore earn 48EE + (60 – 15 =) 45EE = 93EE at the end of the round.
If you as a group invest the same or more than the other group, then you keep what is left of your 20EE starting capital (the same applies to your other group members); and so does the other group. For example: if you and your fellow group members invest 5 each (total of 15) and the other group invest 4 each (total of 12), then you earn 20 – 5 = 15EE.
For your decisions use the form placed on your table. Please use a new form for every round and hand it to the experimenter who will come to collect it. After every round the experimenter will inform you how much each group has invested in that round.
What you have left at the end of every round will decide your eventual takings from this game. The table below contains some examples.
Summary of individual decision
1. For every decision you are coupled to 2 other group members in the neighbouring cubicles and your group is paired with a similar 3 person group.
2. Your investments are anonymous and can result in extra earnings for you. 3. You will keep what you have left of your starting capital if your group invests the same or more
than the other group. If you invest less than the other group then the other group will receive what you have left-over and you will earn nothing on that round.
4. At the end of the study we will choose a few random rounds of the game and based on the decisions you and the other participants made in these rounds we will calculate your earnings. These will be added to the basic participation fee.
Proefpersoonnummer _____
Oefenvragen
1. Aan het begin van de ronde krijgt elke speler 20EE. U investeert 5EE, uw groepsgenoten
investeren samen nog 12EE, en de andere groep investeert in totaal 13EE. Met deze informatie geef een antwoord voor de volgende vragen:
Uw persoonlijke inkomsten zijn _____ (geef een getal tussen 0 en 20)
De andere groep hield _______ over na de investeringsronde (geef een getal tussen de 0 en
60).
Ze kregen ________ van uw groep (geef een getal tussen 0 en 60).
Dus in totaal de andere groep verkregen _________(geef een getal tussen de 0 en 120).
2. Aan het begin van de ronde krijgt elke speler 20EE. U investeert 2EE, uw groepsgenoten
investeren samen nog 2EE, en de andere groep investeert in totaal 15EE. Met deze informatie geef een antwoord voor de volgende vragen:
Uw persoonlijke inkomsten zijn _____ (geef een getal tussen 0 en 20)
De andere groep hield _______ over na de investeringsronde (geef een getal tussen de 0 en
60).
Ze kregen ________ van uw groep (geef een getal tussen 0 en 60).
Participant number ____
Exercises
1. At the beginning of the round, each player receives 20EE. You invest 5EE,
your group members invest 12EE together, and the other group invests 13EE in total.
Your personal earnings are ____ (fill-in a number between 0 and 20). The other group had _____ left after the round of investments (fill-in a
number between 0 and 60).
The other group received ____ from your group (fill-in a number
between 0 and 60).
Therefore, in total the other group earned ____ (fill-in a number between 0 and 120)
2. At the beginning of the round, each player receives 20EE. You invest 2EE,
your group members invest 2EE in total, and the other group invests 15EE in total.
Your personal earnings are ____ (fill-in a number between 0 and 20). The other group had _____ left after the round of investments (fill-in a
number between 0 and 60).
The other group received ____ from your group (fill-in a number
between 0 and 60).
Therefore, in total the other group earned ____ (fill-in a number between 0 and 120).
A5: Instructions, examples, and comprehension questions for prey with punishment, Dutch and English
