Experimental Design
Participants belonging to the two major political groups in Israel will be recruited from a large Israeli online panel. Participants will be asked to privately make a series of binary choices, and in particular to state their opinions on a variety of policy suggestions, and to choose between pairs of real-effort tasks. To allow social learning, choice items will ideally involve uncertainty about their intrinsic value. Real-effort tasks will be introduced by a short description, and participants will be informed that the payoffs and time to completion will be the same for both tasks in each task pair. Hence the uncertainty regarding task pairs will be on the relative effort required for each task.
Choice items will be selected based on a preliminary survey, and will ideally reduce preexisting group dispositions and beliefs about group norms. Preliminary survey participants were randomly assigned to receive or not receive detailed examples of the real-effort tasks (in addition to receiving short task descriptions). The detailed examples serve as an additional informative signal about the relative effort required for each task.
Survey participants will be randomly assigned to receive or not receive social information. Those who receive social information will be matched with a random sample of each political group participating in the preliminary survey. Before making each choice, they will be informed of the descriptive norms prevailing in the samples of political groups assigned to them. The information about norms will include a description of the distribution of choices in the sample of each social group (e.g., a% of Group A chose option x, and (1-a)% of Group A chose option y; b% of Group B chose option x, and (1-b)% of Group B chose option y), alongside a graphic illustration of the distribution. Ideally there should be four main social-information conditions (in addition to the no-information condition), where participants will discover that a majority or minority of their in-group, and a majority or minority of their out-group chose an option, leading to a 2 (in-group majority, in-group minority) X 2 (out-group majority, out-group minority) + 1 (no social information) design.
To create the distribution of choices for the different social-information conditions, while avoiding deception, each survey participant in the treatment group will be matched with an odd-sized small sample from each political group participating in the preliminary survey. The choice items presented to survey participants will be those for which the distribution of choices in the preliminary survey is the closest to uniform. Due to this procedure, we may not have enough identifying variation for some choice items.
In addition, in order to make social learning more meaningful, survey participants will not receive detailed examples of the real-effort tasks, while the samples assigned to participants in the treatment group will mostly consist of preliminary-survey participants who received detailed task examples. To test the effect of signals' informativeness, one half of participants in the treatment group will be informed of that.
Comparing the choices of survey participants observing different (or no) combinations of in-group and out-group norms, will allow us to disentangle the three main channels of social influence. Particularly, let us denote the size of the majority by j% (j>50), and one of the choice options by x. Then participants who receive social information will discover that option x was chosen by either (1) j% of Group A and (1-j)% of Group B, (2) (1-j)% of both groups, (3) (1-j)% of Group A and j% of Group B; or (4) j% of both groups. [Note that the first three conditions, or alternatively conditions (1), (3) and (4), allow separating the main channels].
Social learning alone would predict that the likelihood of choosing option x will be the smallest in condition (2)—where the total relative number of such choices is the smallest—and similarly larger in conditions (1) and (3) that share a similar total relative number of such choices. Yet preferences for in-group conformity and out-group differentiation—whereby resemblance to the typical in-group member and distinction from the typical out-group member, respectively, are sought after—would predict otherwise: For members of Group A, they would predict that the likelihood of choosing x will be the largest in condition (1), smaller in condition (2) and smaller still in condition (3). For members of Group B, they would predict that the likelihood of choosing x will be the largest in condition (3), smaller in condition (2) and smaller still in condition (1). Finally they would predict these differences in the likelihood of choosing x to intensify with the strength of social identity.
Thus comparing the likelihood of choosing x in conditions (1) and (2) will reveal the combined effect of social learning and preferences for in-group conformity for members of Group A [the rival effects of social learning and preferences for out-group differentiation for members of Group B]. Comparing the likelihood of choosing x in conditions (2) and (3) will reveal the rival effects of social learning and preferences for out-group differentiation for members of Group A [the combined effect of social learning and preferences for in-group conformity for members of Group B]. Comparing the likelihood of choosing x in conditions (1) and (3) will reveal the combined effect of preferences for in-group conformity and out-group differentiation for members of both group. Comparing the difference in likelihoods of choosing x of members of Group A [B] between conditions (1) and (3), with the difference in their likelihoods of choosing x between conditions (2) and (3) [(1) and (2)] will allow to separate social learning from preferences for in-group conformity. Moreover, replacing condition (2) with condition (4) will allow us to test the generalizability of the results, as well as drive the combined effect of social learning and preferences for in-group conformity [the rival effects of social learning and preferences for out-group differentiation] while controlling for preferences for out-group differentiation [preferences for in-group conformity]. Finally, the likelihood of choosing x in the no-information condition will capture the groups' tastes and private information about intrinsic value.
After choices are made, one of the participant's task choices will be randomly selected. The participant will then be able to perform that task to receive payment in addition to a participation fee. Each participant will also be asked to complete a brief survey, which will include questions about their reasoning during the experiment, standard psychological questionnaires, demographics, and feedback to the researchers. We are interested in also exploring differences in in-group conformity, out-group differentiation and social learning by education and gender, and in exploring differences in task performance by the social information on task choices.