Search

We conduct a public goods game experiment on cooperation and punishment in changing groups. We arbitrarily categorize participants into three colours: blue, red, or green*. Each participant receives an endowment of 20 monetary units and can choose to keep these units in a private account that only benefits oneself or to contribute them to two types of public goods: a colour-specific public good that gives a return of 0.7 to members of one's own colour and a global public good that gives a return of 0.5 to all members regardless of their colour. There are four members per group. In the first part of the experiment, we let participants play 10 rounds of the public goods game in their group in one of two conditions. This repeated interaction allows participants to develop group norms on how much to contribute to each of the two public goods. In one condition, groups are homogeneous in terms of colour. In the other condition, groups are heterogeneous in terms of colour (i.e., 2 members of one colour are matched with 2 members of another colour). After the first 10 rounds of the public goods game, we replace 2 members per group with 2 new members from another group and start the second part of the experiment. In the condition where groups were homogeneous prior to membership replacement, the replacement leads to heterogeneous groups (e.g., in a group with 4 blue members, 2 of the blue members are replaced by red members). We refer to this condition as HOM-HET. In the condition where groups were heterogeneous prior to membership replacement, the replacement leads to homogeneous groups (e.g., in a group with 2 blue and 2 red members, the 2 red members are replaced by 2 blue members). We refer to this condition as HET-HOM. The reshaped groups in both conditions then play another 10 rounds of the public goods game. In both conditions, we additionally vary whether peer punishment is possible, giving a total of 2 x 2 = 4 sub-conditions: 1: groups that move from homogeneity to heterogeneity due to membership change, without the option to peer-punish, 2: groups that move from heterogeneity to homogeneity due to membership change, without the option to peer-punish, 3: groups that move from homogeneity to heterogeneity due to membership change, with the option to peer-punish, 4: groups that move from heterogeneity to homogeneity due to membership change, with the option to peer-punish. * three colours are needed when there is an uneven number of groups in the laboratory and we want to switch members between groups such that each reshaped group consists of two members of one colour and two members of another colour. With an even number of groups, we only use red and blue colours.

We are conducting a public goods game experiment on cooperation and punishment in changing groups. Subjects will be categorized by their ethnicity (i.e., Israeli Jews and Israeli/Palestinian Arabs). Each subject receives an endowment of 20 monetary units and can choose to keep these units in a private account that only benefits oneself or to contribute them to two types of public goods: a local public good that gives a return of 0.7 to members of one's own ethnicity and a global public good that gives a return of 0.5 to all members regardless of their ethnicity. There are four members per group. In the first part of the experiment, we let subjects play 10 rounds of the public goods game in their group in one of two conditions. This repeated interaction allows subjects to develop group norms on how much to contribute to each of the two public goods. In one condition, groups begin homogeneous in terms of ethnicity. In the other condition, groups begin heterogeneous in terms of ethnicity (i.e., 2 Arabs and 2 Jews). After the first 10 rounds of the public goods game, we replace 2 members per group with 2 new members from another group and start the second part of the experiment. In the condition where groups began homogenous, they now become heterogeneous (e.g., after the first 10 rounds of the game, in groups with 4 Arab members, 2 of the Arab members are replaced by 2 Jewish members). We refer to this condition as HOM-HET. In the condition where groups began heterogeneous, the replacement leads to homogenous groups (e.g., in a group with 2 Arab and 2 Jewish members, the 2 Jewish members are replaced by 2 Arab members). We refer to this condition as HET-HOM. The reshaped groups in both conditions then play another 10 rounds of the public goods game. In both conditions, following each round of the public goods game, subjects can pay a fee to punish other group members by reducing points from their income.

Cooperation in groups often requires individual members to make costly contributions that benefit the group as a whole. Prior research suggests that shared norms can help to support ingroup cooperation by prescribing common standards of how much to contribute. These common standards may be disrupted when groups undergo membership change, i.e., when members from outgroups enter the ingroup. When newcomers and incumbents have different notions about how much to contribute, a normative disagreement ensues that could undermine cooperation and the extent to which individuals identify with the group. In a laboratory experiment, we manipulate whether newcomers and incumbents disagree about how much to contribute in a public goods game with peer punishment. We examine whether normative disagreement between newcomers and incumbents affects newcomer-incumbent relations in terms of group identification, the emergence of a social norm, and costly punishment. The main goal is to test whether normative disagreement and the resulting newcomer-incumbent relations harm cooperation in terms of contributions to the common good. We find that normative disagreement between newcomers and incumbents negatively affects the emergence of a shared social norm and lowers feelings of group identification. Contrary to expectations, normative disagreement does not affect cooperation negatively. Instead, participants adjust their behavior to each other’s standards, using punishment for norm enforcement. This punishment is especially directed at low-contributing newcomers, leading them to conform to the incumbents’ higher contribution standards.

Norms can promote human cooperation to provide public goods. Yet, the potential of norms to promote cooperation may be limited to homogeneous groups in which all members benefit equally from the public good. Individual heterogeneity in the benefits of public good provision is commonly conjectured to bring about normative disagreements that harm cooperation. However, the role of these normative disagreements remains unclear because they are rarely directly measured or manipulated. In a laboratory experiment, we first measure participants’ views on the appropriate way to contribute to a public good with heterogeneous returns. We then use this information to sort people into groups that either agree or disagree on these views, thereby manipulating group-level disagreement on normative views. Participants subsequently make several incentivized contribution decisions in a public goods game with peer punishment. We find that although there are considerable disagreements about individual contribution levels in heterogeneous groups, these disagreements do not impede cooperation. While cooperation is maintained because low contributors are punished, participants do not use punishment to impose their normative views on others. The contribution levels at which groups cooperate strongly relate to the average normative views of these groups.