Supplementary Information for Societal background influences social learning in cooperative decision making Authors Lucas Mollemana,b, * and Simon Gächterc,d Affiliations a
University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
b
Center for Adaptive Rationality, Max Planck Institute for Human Development, Lentzeallee 94, 14195
Berlin, Germany c
Center for Economic Studies, Poschingerstraße 5, 81679 Munich, Germany
d
Institute of Labour Economics, Schaumburg-Lippe-Strasse 5-9, 53113 Bonn, Germany
* Corresponding author.
[email protected]
Contents
Supplementary Figures
Supplementary Tables
Supplementary Analysis
Supplementary Experimental Procedures 1. 2. 3. 4.
Cross-societal implementation Experimental procedures Paper instructions On-screen instructions
Supplementary References
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Figure S1. Questionnaire items: attitudes towards conformity. Our post-experimental questionnaire included four statements referring to items measuring participants’ attitudes towards conformity (Schwartz, 1994). On-screen instructions stated: “Here we briefly describe some people. Please read each description and indicate the extent to which you think each person is or is not like you.”, followed by these four statements: (a) “He believes that people should do what they’re told. He thinks people should follow rules at all times, even when no-one is watching.” (b) “It is important to him to behave properly. He wants to avoid doing anything people would say is wrong.” (c) “It is important to him to be obedient. He believes he should always show respect to his parents and to older people.” (d) “It is important to him to be polite to other people all the time. He tries never to disturb or irritate others.” Participants rated each of these statements on a Likert scale from 1 (‘very much like me’) to 7 (‘not at all like me’). In each panel (a-d), bars show distributions for each statement for China and the United Kingdom in orange and grey, respectively. Statistics reported in the main text refer to composite scores averaging across the four items for each country separately, with the attitude towards conformity being inversely related to each of the items (means: China 4.534; United Kingdom 5.638). Pronouns in the item descriptions were adapted according to gender; the item list (a-d) shows masculine form only.
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Figure S2. Questionnaire item: Inclusion of the Other in the Self. Our post-experimental questionnaire included this item (adapted from Aron, Aron, & Smollan, 1992) as a proxy of perceived interdependence. This measure is commonly used in the social sciences and considered to be a psychologically meaningful and highly reliable measure of the subjective closeness of relationships (Gächter, Starmer, & Tufano, 2015). Grey and orange bars respectively show the distributions for China and the United Kingdom; means: United Kingdom 4.145, China 4.441, where A=1 and G=7).
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Figure S3. Dynamics of group behavior and social information requests for the social dilemma. Solid and hatched bars reflect data from China and the United Kingdom, respectively. Each bar combines decisions from each of the four five-period blocks of each interaction setting. Stacked bars in panel (a) show fractions of groups in each of the six possible states (with 0, 1, 2, 3, 4 or 5 individuals choosing behavior A). Darker colors indicate states closer to the equilibrium where all group members choose B (‘defect’). Arrows at the borders of the stacked bars indicate the expected direction of change based on underlying payoff matrices. We observe that the relative fraction of darker bars increases over time, indicating that cooperation tends to decrease over time. This observation is supported by logistic GLMMs (with participant nested in session as random effect) detecting decreasing frequencies of cooperation over time (p
