Table 2. Summary of commonly used economic games and game variants thereof
 Game Structure Payoffs (u) Broad affordance(s) Social motive(s)a Sequential resource-allocation games Dictator Game A dictator (D) receives an endowment (e) and freely decides how much to keep versus give (g) to a recipient (R) $$u_{D}=e-g$$ $$u_{R}=g$$ Exploitation altruism, fairness vs. greed, competitiveness, spite Triple Dictator Game … D’s transfer to R is tripled. $$u_{D}=e-g$$ $$u_{R}=3 g$$ Exploitation altruism, fairness, social welfare vs. greed, competitiveness, spite Generosity Game … D’s payoff is fixed and D simply decides on R’s payoff. $$u_{D}=e$$ $$u_{R}=g$$ Exploitation altruism, fairness, social welfare vs. competitiveness, spite Solidarity Game … D and two recipients R1 and R2 each can win e in a lottery. D decides in advance how much of e to give (g) to R1 and/or R2 if D wins e in the lottery and either or both of R1 and R2 lose in the lottery. if either $$R 1$$ or $$R 2$$ loses: $$u_{D}=e-g$$ $$u_{R 1}=g$$ or $$u_{R 2}=g$$ $$u_{R 2}= e$$ or $$u_{R 1}=e$$ if both $$R 1$$ and $$R 2$$ lose: $$u_{D}=e-2^{*} g$$ $$u_{R 1}=g$$ $$u_{R 2}=g$$ Exploitation altruism, fairness vs. greed, competitiveness, spite Faith Game … R can choose whether to receive g or a fixed amount f < $$\frac{e}{2}$$. $$u_{D}=e-g$$ $$u_{R} \in\{g, f\}$$ Dependence N/A Ultimatum Game A proposer (P) receives an endowment (e) and decides how much to keep versus give (g) to a recipient (R). R is empowered to accept versus reject P’s offer which affects both players’ payoffs. if $$R$$ accepts: $$u_{P}=e-g$$ $$u_{R}=g$$ if $$R$$ rejects: $$u_{P}=u_{R}=0$$ P: (Exploitation), Temporal conflict, Dependence; R: Reciprocity, Temporal conflict P: altruism, fairness vs. greed, competitiveness, spite R: altruism, greed, social welfare vs. competitiveness, spite Impunity Game … R’s decision only affects R’s own payoff. if $$R$$ accepts: $$u_{P}=e-g$$ $$u_{R}=g$$ if $$R$$ rejects: $$u_{P}=e-g$$ $$u_{R}=0$$ P: Exploitation; R: Reciprocity, Temporal conflict P: altruism, fairness vs. greed, competitiveness, spite R: greed, social welfare vs. (none) Spite Game … R’s decision only affects P’s payoff. if $$R$$ accepts: $$u_{P}=e-g$$ $$u_{R}=g$$ if $$R$$ rejects: $$u_{P}=0$$ $$u_{R}=g$$ P: (Exploitation), Temporal conflict, Dependence; R: Reciprocity P: altruism, fairness vs. greed, competitiveness, spite R: altruism, social welfare vs. competitiveness, spite Three-person Ultimatum Game … P divides e between R and a passive bystander (B). R’s decision affects all three players. if $$R$$ accepts: $$u_{P}=e-g_{R}-g_{B}$$ $$u_{R}=g_{R}$$ $$u_{B}=g_{B}$$ if $$R$$ rejects: $$u_{P}=u_{R}=u_{B}=0$$ P: (Exploitation), Temporal conflict, Dependence; R: Reciprocity, Temporal conflict P: altruism, fairness vs. greed, competitiveness, spite R: altruism, greed, social welfare vs. competitiveness, spite Rubinstein Bargaining Game … if R rejects P’s offer, bargaining continues with R making a new offer to P and so on. The game ends once an offer is accepted by either player. Bargaining time is costly, with discounting factor 0 < t < 1 decreasing in each round. $$u_{P}=(e-g)^{*} t$$ $$u_{R}=g^{*} t$$ (Exploitation), Reciprocity, Temporal conflict, Dependence altruism, social welfare vs. greed, competitiveness, spite Power-to-Take Game … both P and R have to earn their endowment (eP and eR, respectively) in an effortful task. P then decides on the proportion (t) to take from eR. Before the corresponding amount is transferred to P, R can destroy any proportion (d) of eR. $$u_{P}=e_{P}+t^{*}(1-d)^{*} e_{R}$$ $$u_{R}=(1-t)^{*}(1-d)^{*} e_{R}$$ P: Exploitation, Temporal conflict, Dependence; R: Reciprocity; Temporal conflict P: altruism, fairness vs. greed, competitiveness, spite R: altruism, greed, social welfare vs. competitiveness, spite Trust Game A trustor (I) divides an endowment (e) between herself and a trustee (T). The transferred amount (g) is multiplied by a constant (m) and added to T’s endowment. T can return any amount (r) of g * m to I. $$u_{I}=e-g+r$$ $$u_{T}=e+m^{*} g-r$$ I: (Exploitation), Dependence; T: Exploitation, (Reciprocity) I: altruism, social welfare vs. greed, competitiveness, spite; T: altruism, fairness vs. greed, competitiveness, spite Moonlighting Game … I cannot only send g ≤ $$\frac{e}{2}$$ tokens to T but can alternatively take t ≤ $$\frac{e}{2}$$ tokens from T. In turn, T cannot only return r ≤ m * $$\frac{e}{2}$$ tokens but can alternatively reduce I’s payoff by m * p tokens at cost p. $$u_{I}=e-g+t+r-m^{*} p$$ $$u_{T}=e+m^{*} g-t-r-p$$ I: Exploitation, Temporal conflict, Dependence; T: Exploitation, (Reciprocity) I: altruism, social welfare vs. greed, competitiveness, spite; T: altruism, fairness vs. greed, competitiveness, spite Distrust Game … I does not receive an initial endowment but T is endowed with eT = m * e + e. I decides how much to take (t) from eT, with t being divided by m. T then decides how much to give (r) to I. $$u_{I}=\frac{t}{m}+r$$ $$u_{T}=e_{T}-t-r$$ I: (Exploitation), Dependence; T: Exploitation, (Reciprocity) I: altruism, social welfare vs. competitiveness, spite; T: altruism, fairness vs. greed, competitiveness, spite Social dilemmas Prisoner’s Dilemma Two players decide independently whether to cooperate or defect. Their payoffs depend on the combination of players’ strategies. The maximum individual payoff results from unilateral defection, the minimum from unilateral cooperation. Exploitation, Dependence altruism, social welfare vs. greed, competitiveness, spite C D C R | R S | T D T | S P | P with T > R > P > S Prisoner’s Dilemma-Alt … a third “withdrawal” option W is added that realizes a fixed payoff E for both players. Exploitation, (Dependence) altruism, social welfare (C) vs. greed, competitiveness, spite (D) C D W C R | R S | T E | E D T | S P | P E | E W E | E E | E E | E with T > R > E > P > S Prisoner’s Dilemma-R … a third (defective) option Drel is added that realizes a lower absolute payoff for the selecting player, but a higher relative payoff in comparison to the other player. Exploitation, Dependence altruism, social welfare (C) vs. greed (D) vs. competitiveness, spite (Drel) C D Drel C R | R S | T E | R D T | S P | P F | S Drel R | E S | F E | E with T > R > P > S > F > E; in addition, R/E > T/S and S/F > 1 Prisoner’s Dilemma with variable dependence …each player independently chooses their dependence on the other player before making a decision on whether to cooperate or defect. similar to the Prisoner’s Dilemma, with T – R and P – S becoming larger (smaller) for high (low) dependence Exploitation, (Dependence) altruism, social welfare vs. greed, competitiveness, spite Public Goods Game Each member i of a group of size N decides how much ( gi) of an individual endowment (e) to contribute to a group account. Contributions are multiplied by a constant m (with 1 < m < N) and shared equally across all group members. $${u}_{i}$$ $$=$$ $$e$$ $$–$$ $${g}_{i}{+}\frac{m*\sum_{j=1}^N {g}_{j}}{N}$$ Exploitation, Dependence altruism, social welfare vs. greed, competitiveness, spite Step-level Public Goods Game … resources in the group account are only shared equally across group members if a contribution threshold t is reached $${u}_{i}$$ $$=$$ $${e}$$ $$–{g}_{i}+$$ $${x}$$ $$*\frac{m*\sum_{j=1}^{N}{g}_{j}}{N}$$ with x = 1 if $$\sum_{j=1}^N {g}_{j}{≥}$$ $${t}$$ and x = 0 otherwise (Exploitation), Temporal conflict, Dependence altruism, social welfare vs. greed, competitiveness, spite Commons Dilemma … group members decide how much (tiz) to take from a common resource Cz (with tiz ≤ Cz) in round z. Following each round, Cz recovers with reproduction rate r > 1: Cz+1 = (Cz – $$\sum_{j=1}^N {t}_{i}^{z}$$) * r. The game ends once the amount Cz+x available in round z + x is depleted, that is, if the collective consumption $$\sum_{j=1}^N {t}_{j}^{z+x}$$ ≥ Cz+x. $${u}_{i}=$$ $$\sum_{z}^{}{t}_{i}^{z}$$ Exploitation, Temporal conflict (assuming z > 1) Dependence altruism, social welfare vs. greed, competitiveness, spite Volunteer’s Dilemma … group members decide between cooperation (volunteering) and defection (somebody else should do the job). If at least one player cooperates, a public good of value v is provided. Cooperation comes with costs c < v. $$u_{i}=v-c$$ if $$i$$ cooperates; $$u_{j}=v$$ if $$i$$ defects but at least one other player cooperates; $$u_{i}=0$$ otherwise Exploitation, Temporal conflict, Dependence altruism, social welfare vs. competitiveness, spite Intergroup Prisoner’s Dilemma Each player i (of N > 3 players) is assigned to one of two group with n = $$\frac{N}{2}$$ members and decides how much (gBi) of their individual endowment (e) to contribute to a group account (between-group pool B). Contributions are multiplied by a constant m (with 1 < m < n). Every token contributed increases the payoff of players from i’s in-group I and decreases the payoff of players from i’s out-group O by $$\frac{m}{n}$$. $${u}_{i}$$ $$=$$ $$e$$$$- {g}_{Bi}$$$$+ \frac{m}{n}\sum_{j=1}^{n}{g}_{Bj}$$$$- \frac{m}{n}\sum_{k=n+1}^{N}{g}_{Bk}$$ Exploitation, Dependence in-group altruism, in-group welfare, out-group competitiveness, out-group spite vs. greed, collective altruism, collective welfare, in-group competitiveness, in-group spite Intergroup Prisoner’s Dilemma–Maximizing Difference …a second group account (within-group pool W) is added. Every token gWi contributed to this pool increases the payoff of players from the in-group I by $$\frac{m}{n}$$ without affecting the payoff of players from the out-group O. $${u}_{i}$$ $$=$$ $$e$$ $$-$$ $${g}_{Wi}$$$$- {g}_{Bi}$$$$+ \frac{m}{n}\sum_{j=1}^{n}{g}_{Wj}$$$${+}\frac{m}{n}\sum_{j=1}^{n}{g}_{Bj}$$$$- \frac{m}{n}\sum_{k=n+1}^{N}{g}_{Bk}$$ Exploitation, Dependence in-group altruism, in-group welfare, out-group competitiveness, out-group spite (B) vs. in-group altruism, collective welfare (W) vs. greed, in-group competitiveness, in-group spite (keep) Positive Intergroup Prisoner’s Dilemma–Maximizing Difference …the group account is replaced by two different group accounts. In the within-group pool W, every token contributed increases the payoff of players from the in-group I by $$\frac{m}{n}$$ without affecting the payoff of players from the out-group O. In the between-group pool B, every token contributed increases the payoff of players from the in-group I and from the out-group O by $$\frac{m}{n}$$. $${u}_{i}$$ $$=$$ $${e}$$ $$-$$ $${g}_{Wi}$$$$- {g}_{Bi}$$$$+ \frac{m}{n}\sum_{j=1}^{n}{g}_{Wj}$$$${+}\frac{m}{n}\sum_{j=1}^{n}{g}_{Bj}$$$$+ \frac{m}{n}\sum_{k=n+1}^{N}{g}_{Bk}$$ Exploitation, Dependence in-group altruism, in-group welfare, out-group spite, out-group competitiveness (W) vs. collective altruism, collective welfare, in-group altruism (B) vs. greed, collective competitiveness, collective spite, in-group competitiveness, in-group spite, out-group spite (keep) Intergroup Parochial and Universal Cooperation Game …adds another group account (universal pool U) to the Intergroup Prisoner’s Dilemma – Maximizing Difference Game. Each token contributed to this pool increases the payoff of players from both the in-group I and the out-group O by $$\frac{q}{N}$$, with N > q > m and $$\frac{q}{N}$$ < $$\frac{m}{n}$$. $${u}_{i}$$ $$=$$ $$e$$ $$-$$ $${g}_{Wi}$$$$- {g}_{Bi}-$$ $${g}_{Ui}$$$$+ \frac{m}{n}\sum_{j=1}^{n}{g}_{Wj}$$$${+}\frac{m}{n}\sum_{j=1}^{n}{g}_{Bj}{+}\frac{q}{N}\sum_{j=1}^{n}{g}_{Uj}$$ $${+}\frac{q}{N}\sum_{k=n+1}^{n}{g}_{Uk}$$$$-$$ $$\frac{m}{n}\sum_{k=n+1}^{N}{g}_{Bk}$$ Exploitation, Dependence in-group altruism, in-group welfare, out-group competitiveness, out-group spite (B) vs. in-group altruism, in-group welfare (W) vs. social welfare (U) vs. greed, in-group competitiveness, in-group spite (keep)
 Game Structure Payoffs (u) Broad affordance(s) Social motive(s)a Sequential resource-allocation games Dictator Game A dictator (D) receives an endowment (e) and freely decides how much to keep versus give (g) to a recipient (R) $$u_{D}=e-g$$ $$u_{R}=g$$ Exploitation altruism, fairness vs. greed, competitiveness, spite Triple Dictator Game … D’s transfer to R is tripled. $$u_{D}=e-g$$ $$u_{R}=3 g$$ Exploitation altruism, fairness, social welfare vs. greed, competitiveness, spite Generosity Game … D’s payoff is fixed and D simply decides on R’s payoff. $$u_{D}=e$$ $$u_{R}=g$$ Exploitation altruism, fairness, social welfare vs. competitiveness, spite Solidarity Game … D and two recipients R1 and R2 each can win e in a lottery. D decides in advance how much of e to give (g) to R1 and/or R2 if D wins e in the lottery and either or both of R1 and R2 lose in the lottery. if either $$R 1$$ or $$R 2$$ loses: $$u_{D}=e-g$$ $$u_{R 1}=g$$ or $$u_{R 2}=g$$ $$u_{R 2}= e$$ or $$u_{R 1}=e$$ if both $$R 1$$ and $$R 2$$ lose: $$u_{D}=e-2^{*} g$$ $$u_{R 1}=g$$ $$u_{R 2}=g$$ Exploitation altruism, fairness vs. greed, competitiveness, spite Faith Game … R can choose whether to receive g or a fixed amount f < $$\frac{e}{2}$$. $$u_{D}=e-g$$ $$u_{R} \in\{g, f\}$$ Dependence N/A Ultimatum Game A proposer (P) receives an endowment (e) and decides how much to keep versus give (g) to a recipient (R). R is empowered to accept versus reject P’s offer which affects both players’ payoffs. if $$R$$ accepts: $$u_{P}=e-g$$ $$u_{R}=g$$ if $$R$$ rejects: $$u_{P}=u_{R}=0$$ P: (Exploitation), Temporal conflict, Dependence; R: Reciprocity, Temporal conflict P: altruism, fairness vs. greed, competitiveness, spite R: altruism, greed, social welfare vs. competitiveness, spite Impunity Game … R’s decision only affects R’s own payoff. if $$R$$ accepts: $$u_{P}=e-g$$ $$u_{R}=g$$ if $$R$$ rejects: $$u_{P}=e-g$$ $$u_{R}=0$$ P: Exploitation; R: Reciprocity, Temporal conflict P: altruism, fairness vs. greed, competitiveness, spite R: greed, social welfare vs. (none) Spite Game … R’s decision only affects P’s payoff. if $$R$$ accepts: $$u_{P}=e-g$$ $$u_{R}=g$$ if $$R$$ rejects: $$u_{P}=0$$ $$u_{R}=g$$ P: (Exploitation), Temporal conflict, Dependence; R: Reciprocity P: altruism, fairness vs. greed, competitiveness, spite R: altruism, social welfare vs. competitiveness, spite Three-person Ultimatum Game … P divides e between R and a passive bystander (B). R’s decision affects all three players. if $$R$$ accepts: $$u_{P}=e-g_{R}-g_{B}$$ $$u_{R}=g_{R}$$ $$u_{B}=g_{B}$$ if $$R$$ rejects: $$u_{P}=u_{R}=u_{B}=0$$ P: (Exploitation), Temporal conflict, Dependence; R: Reciprocity, Temporal conflict P: altruism, fairness vs. greed, competitiveness, spite R: altruism, greed, social welfare vs. competitiveness, spite Rubinstein Bargaining Game … if R rejects P’s offer, bargaining continues with R making a new offer to P and so on. The game ends once an offer is accepted by either player. Bargaining time is costly, with discounting factor 0 < t < 1 decreasing in each round. $$u_{P}=(e-g)^{*} t$$ $$u_{R}=g^{*} t$$ (Exploitation), Reciprocity, Temporal conflict, Dependence altruism, social welfare vs. greed, competitiveness, spite Power-to-Take Game … both P and R have to earn their endowment (eP and eR, respectively) in an effortful task. P then decides on the proportion (t) to take from eR. Before the corresponding amount is transferred to P, R can destroy any proportion (d) of eR. $$u_{P}=e_{P}+t^{*}(1-d)^{*} e_{R}$$ $$u_{R}=(1-t)^{*}(1-d)^{*} e_{R}$$ P: Exploitation, Temporal conflict, Dependence; R: Reciprocity; Temporal conflict P: altruism, fairness vs. greed, competitiveness, spite R: altruism, greed, social welfare vs. competitiveness, spite Trust Game A trustor (I) divides an endowment (e) between herself and a trustee (T). The transferred amount (g) is multiplied by a constant (m) and added to T’s endowment. T can return any amount (r) of g * m to I. $$u_{I}=e-g+r$$ $$u_{T}=e+m^{*} g-r$$ I: (Exploitation), Dependence; T: Exploitation, (Reciprocity) I: altruism, social welfare vs. greed, competitiveness, spite; T: altruism, fairness vs. greed, competitiveness, spite Moonlighting Game … I cannot only send g ≤ $$\frac{e}{2}$$ tokens to T but can alternatively take t ≤ $$\frac{e}{2}$$ tokens from T. In turn, T cannot only return r ≤ m * $$\frac{e}{2}$$ tokens but can alternatively reduce I’s payoff by m * p tokens at cost p. $$u_{I}=e-g+t+r-m^{*} p$$ $$u_{T}=e+m^{*} g-t-r-p$$ I: Exploitation, Temporal conflict, Dependence; T: Exploitation, (Reciprocity) I: altruism, social welfare vs. greed, competitiveness, spite; T: altruism, fairness vs. greed, competitiveness, spite Distrust Game … I does not receive an initial endowment but T is endowed with eT = m * e + e. I decides how much to take (t) from eT, with t being divided by m. T then decides how much to give (r) to I. $$u_{I}=\frac{t}{m}+r$$ $$u_{T}=e_{T}-t-r$$ I: (Exploitation), Dependence; T: Exploitation, (Reciprocity) I: altruism, social welfare vs. competitiveness, spite; T: altruism, fairness vs. greed, competitiveness, spite Social dilemmas Prisoner’s Dilemma Two players decide independently whether to cooperate or defect. Their payoffs depend on the combination of players’ strategies. The maximum individual payoff results from unilateral defection, the minimum from unilateral cooperation. Exploitation, Dependence altruism, social welfare vs. greed, competitiveness, spite C D C R | R S | T D T | S P | P with T > R > P > S Prisoner’s Dilemma-Alt … a third “withdrawal” option W is added that realizes a fixed payoff E for both players. Exploitation, (Dependence) altruism, social welfare (C) vs. greed, competitiveness, spite (D) C D W C R | R S | T E | E D T | S P | P E | E W E | E E | E E | E with T > R > E > P > S Prisoner’s Dilemma-R … a third (defective) option Drel is added that realizes a lower absolute payoff for the selecting player, but a higher relative payoff in comparison to the other player. Exploitation, Dependence altruism, social welfare (C) vs. greed (D) vs. competitiveness, spite (Drel) C D Drel C R | R S | T E | R D T | S P | P F | S Drel R | E S | F E | E with T > R > P > S > F > E; in addition, R/E > T/S and S/F > 1 Prisoner’s Dilemma with variable dependence …each player independently chooses their dependence on the other player before making a decision on whether to cooperate or defect. similar to the Prisoner’s Dilemma, with T – R and P – S becoming larger (smaller) for high (low) dependence Exploitation, (Dependence) altruism, social welfare vs. greed, competitiveness, spite Public Goods Game Each member i of a group of size N decides how much ( gi) of an individual endowment (e) to contribute to a group account. Contributions are multiplied by a constant m (with 1 < m < N) and shared equally across all group members. $${u}_{i}$$ $$=$$ $$e$$ $$–$$ $${g}_{i}{+}\frac{m*\sum_{j=1}^N {g}_{j}}{N}$$ Exploitation, Dependence altruism, social welfare vs. greed, competitiveness, spite Step-level Public Goods Game … resources in the group account are only shared equally across group members if a contribution threshold t is reached $${u}_{i}$$ $$=$$ $${e}$$ $$–{g}_{i}+$$ $${x}$$ $$*\frac{m*\sum_{j=1}^{N}{g}_{j}}{N}$$ with x = 1 if $$\sum_{j=1}^N {g}_{j}{≥}$$ $${t}$$ and x = 0 otherwise (Exploitation), Temporal conflict, Dependence altruism, social welfare vs. greed, competitiveness, spite Commons Dilemma … group members decide how much (tiz) to take from a common resource Cz (with tiz ≤ Cz) in round z. Following each round, Cz recovers with reproduction rate r > 1: Cz+1 = (Cz – $$\sum_{j=1}^N {t}_{i}^{z}$$) * r. The game ends once the amount Cz+x available in round z + x is depleted, that is, if the collective consumption $$\sum_{j=1}^N {t}_{j}^{z+x}$$ ≥ Cz+x. $${u}_{i}=$$ $$\sum_{z}^{}{t}_{i}^{z}$$ Exploitation, Temporal conflict (assuming z > 1) Dependence altruism, social welfare vs. greed, competitiveness, spite Volunteer’s Dilemma … group members decide between cooperation (volunteering) and defection (somebody else should do the job). If at least one player cooperates, a public good of value v is provided. Cooperation comes with costs c < v. $$u_{i}=v-c$$ if $$i$$ cooperates; $$u_{j}=v$$ if $$i$$ defects but at least one other player cooperates; $$u_{i}=0$$ otherwise Exploitation, Temporal conflict, Dependence altruism, social welfare vs. competitiveness, spite Intergroup Prisoner’s Dilemma Each player i (of N > 3 players) is assigned to one of two group with n = $$\frac{N}{2}$$ members and decides how much (gBi) of their individual endowment (e) to contribute to a group account (between-group pool B). Contributions are multiplied by a constant m (with 1 < m < n). Every token contributed increases the payoff of players from i’s in-group I and decreases the payoff of players from i’s out-group O by $$\frac{m}{n}$$. $${u}_{i}$$ $$=$$ $$e$$$$- {g}_{Bi}$$$$+ \frac{m}{n}\sum_{j=1}^{n}{g}_{Bj}$$$$- \frac{m}{n}\sum_{k=n+1}^{N}{g}_{Bk}$$ Exploitation, Dependence in-group altruism, in-group welfare, out-group competitiveness, out-group spite vs. greed, collective altruism, collective welfare, in-group competitiveness, in-group spite Intergroup Prisoner’s Dilemma–Maximizing Difference …a second group account (within-group pool W) is added. Every token gWi contributed to this pool increases the payoff of players from the in-group I by $$\frac{m}{n}$$ without affecting the payoff of players from the out-group O. $${u}_{i}$$ $$=$$ $$e$$ $$-$$ $${g}_{Wi}$$$$- {g}_{Bi}$$$$+ \frac{m}{n}\sum_{j=1}^{n}{g}_{Wj}$$$${+}\frac{m}{n}\sum_{j=1}^{n}{g}_{Bj}$$$$- \frac{m}{n}\sum_{k=n+1}^{N}{g}_{Bk}$$ Exploitation, Dependence in-group altruism, in-group welfare, out-group competitiveness, out-group spite (B) vs. in-group altruism, collective welfare (W) vs. greed, in-group competitiveness, in-group spite (keep) Positive Intergroup Prisoner’s Dilemma–Maximizing Difference …the group account is replaced by two different group accounts. In the within-group pool W, every token contributed increases the payoff of players from the in-group I by $$\frac{m}{n}$$ without affecting the payoff of players from the out-group O. In the between-group pool B, every token contributed increases the payoff of players from the in-group I and from the out-group O by $$\frac{m}{n}$$. $${u}_{i}$$ $$=$$ $${e}$$ $$-$$ $${g}_{Wi}$$$$- {g}_{Bi}$$$$+ \frac{m}{n}\sum_{j=1}^{n}{g}_{Wj}$$$${+}\frac{m}{n}\sum_{j=1}^{n}{g}_{Bj}$$$$+ \frac{m}{n}\sum_{k=n+1}^{N}{g}_{Bk}$$ Exploitation, Dependence in-group altruism, in-group welfare, out-group spite, out-group competitiveness (W) vs. collective altruism, collective welfare, in-group altruism (B) vs. greed, collective competitiveness, collective spite, in-group competitiveness, in-group spite, out-group spite (keep) Intergroup Parochial and Universal Cooperation Game …adds another group account (universal pool U) to the Intergroup Prisoner’s Dilemma – Maximizing Difference Game. Each token contributed to this pool increases the payoff of players from both the in-group I and the out-group O by $$\frac{q}{N}$$, with N > q > m and $$\frac{q}{N}$$ < $$\frac{m}{n}$$. $${u}_{i}$$ $$=$$ $$e$$ $$-$$ $${g}_{Wi}$$$$- {g}_{Bi}-$$ $${g}_{Ui}$$$$+ \frac{m}{n}\sum_{j=1}^{n}{g}_{Wj}$$$${+}\frac{m}{n}\sum_{j=1}^{n}{g}_{Bj}{+}\frac{q}{N}\sum_{j=1}^{n}{g}_{Uj}$$ $${+}\frac{q}{N}\sum_{k=n+1}^{n}{g}_{Uk}$$$$-$$ $$\frac{m}{n}\sum_{k=n+1}^{N}{g}_{Bk}$$ Exploitation, Dependence in-group altruism, in-group welfare, out-group competitiveness, out-group spite (B) vs. in-group altruism, in-group welfare (W) vs. social welfare (U) vs. greed, in-group competitiveness, in-group spite (keep)

Note. N/A = not applicable given that the sub-affordances and corresponding social motives are only relevant in games involving a possibility for exploitation and/or reciprocity. Affordances put in parentheses are present to a relatively weaker degree (see main text for details). In the payoff matrices (Prisoner’s Dilemma and variants thereof), T = temptation, R = reward, P = punishment, S = sucker (see main text for details). For a detailed description of all game variants, see the online supplement https://osf.io/t8m7x/. a Motives listed first (before “vs.”) are afforded to be expressed in prosocial behavior, motives listed second (after “vs.”) are afforded to be expressed in selfish behavior. We only specify motives that are afforded in general, that is, irrespective of the other player’s decision (e.g., in the Ultimatum Game as responder, we do not mention the motive of fairness because this motive is only afforded if the proposer did not realize a fair split). According to the framework relied on here (Thielmann et al., 2020), social motives are afforded by specific sub-affordances of the exploitation and reciprocity affordances.

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