Abstract
Long Abstract
This paper proposes a theoretical and experimental contribution to the psychological foundations of norm compliance in distributive settings. We introduce the Conformity Preference Model, which formalizes Rawls’ (1971) idea of the sense of justice within the framework of psychological game theory (Geanakoplos et al., 1989; Battigalli and Dufwenberg, 2009, 2022). The model explains why and how impartial agreements –reached ex ante under a veil of ignorance – generate motivational conditions for compliance with fair distributive norms.
Our central hypothesis is that the motivational power of norms depends on two intertwined elements: (i) the deontological commitment to act in accordance with a fair principle, and (ii) the belief that others are equally committed and will conform to the same principle. Thus, the model incorporates belief-dependent utility, not to capture emotional states such as guilt or image concern (e.g. Battigalli and Dufwenberg, 2007; Sebald and Vikander, 2019), but to reflect normative reasoning: agents care about their own conformity with a principle of justice they rationally agreed upon, provided they expect reciprocal conformity.
We assume that the norm is chosen under impartial conditions (Rawls, 1971; Binmore, 2005) – and corresponds to a Nash bargaining solution (Nash, 1950; 1953). The principle is embedded into the players’ utility functions through a conformity index that evaluates the distance between actual behavior and full conformity to the agreed-upon norm, given beliefs about others’ actions and expectations. This generates a psychological payoff component that complements material utility.
Empirically, the model is supported by previously published experimental evidence. In Sacconi and Faillo (2010), participants in an Exclusion Game reached an ex ante agreement on a distributive rule. Those who adhered to the agreed rule in the subsequent game phase were also those who expected others to comply. This alignment between behavior and second-order expectations suggests that agreements shape shared beliefs that act as focal points for normative behavior.
In Faillo, Ottone and Sacconi (2015), varying treatments tested the robustness of compliance to impartial agreements under different group compositions. Results show that compliance is significantly higher when the decision-making group is the same as the agreement group, confirming that the shared experience of impartial deliberation fosters both trust and conformity.
A more recent experiment by Degli Antoni et al. (2022) shows that when subjects are allowed to deliberate under a veil of ignorance about unequal initial endowments, they tend to adopt liberal egalitarian principles that (i) neutralize arbitrary inequalities and (ii) reward individual effort. Notably, these principles continue to guide behavior even after the veil is lifted, particularly when supported by expectations of mutual compliance.
Our framework contributes to the literature in several ways. First, it extends psychological game theory by incorporating explicit normative content into belief-dependent motivations, unlike models that focus solely on emotions or social image (e.g. Rabin, 1993; Dufwenberg and Kirchsteiger, 2004; Tadelis, 2011). Second, it offers a contractarian foundation for norm compliance in distributive contexts, showing that fair agreements can act as equilibrium selection devices by shaping preferences and expectations. Third, it highlights the importance of deliberative processes for institution design: under the right epistemic and motivational conditions, justice-based principles can become self-enforcing.
While our paper does not introduce new empirical data, it provides a unified theoretical account that connects diverse experimental findings within a robust normative framework.
This paper proposes a theoretical and experimental contribution to the psychological foundations of norm compliance in distributive settings. We introduce the Conformity Preference Model, which formalizes Rawls’ (1971) idea of the sense of justice within the framework of psychological game theory (Geanakoplos et al., 1989; Battigalli and Dufwenberg, 2009, 2022). The model explains why and how impartial agreements –reached ex ante under a veil of ignorance – generate motivational conditions for compliance with fair distributive norms.
Our central hypothesis is that the motivational power of norms depends on two intertwined elements: (i) the deontological commitment to act in accordance with a fair principle, and (ii) the belief that others are equally committed and will conform to the same principle. Thus, the model incorporates belief-dependent utility, not to capture emotional states such as guilt or image concern (e.g. Battigalli and Dufwenberg, 2007; Sebald and Vikander, 2019), but to reflect normative reasoning: agents care about their own conformity with a principle of justice they rationally agreed upon, provided they expect reciprocal conformity.
We assume that the norm is chosen under impartial conditions (Rawls, 1971; Binmore, 2005) – and corresponds to a Nash bargaining solution (Nash, 1950; 1953). The principle is embedded into the players’ utility functions through a conformity index that evaluates the distance between actual behavior and full conformity to the agreed-upon norm, given beliefs about others’ actions and expectations. This generates a psychological payoff component that complements material utility.
Empirically, the model is supported by previously published experimental evidence. In Sacconi and Faillo (2010), participants in an Exclusion Game reached an ex ante agreement on a distributive rule. Those who adhered to the agreed rule in the subsequent game phase were also those who expected others to comply. This alignment between behavior and second-order expectations suggests that agreements shape shared beliefs that act as focal points for normative behavior.
In Faillo, Ottone and Sacconi (2015), varying treatments tested the robustness of compliance to impartial agreements under different group compositions. Results show that compliance is significantly higher when the decision-making group is the same as the agreement group, confirming that the shared experience of impartial deliberation fosters both trust and conformity.
A more recent experiment by Degli Antoni et al. (2022) shows that when subjects are allowed to deliberate under a veil of ignorance about unequal initial endowments, they tend to adopt liberal egalitarian principles that (i) neutralize arbitrary inequalities and (ii) reward individual effort. Notably, these principles continue to guide behavior even after the veil is lifted, particularly when supported by expectations of mutual compliance.
Our framework contributes to the literature in several ways. First, it extends psychological game theory by incorporating explicit normative content into belief-dependent motivations, unlike models that focus solely on emotions or social image (e.g. Rabin, 1993; Dufwenberg and Kirchsteiger, 2004; Tadelis, 2011). Second, it offers a contractarian foundation for norm compliance in distributive contexts, showing that fair agreements can act as equilibrium selection devices by shaping preferences and expectations. Third, it highlights the importance of deliberative processes for institution design: under the right epistemic and motivational conditions, justice-based principles can become self-enforcing.
While our paper does not introduce new empirical data, it provides a unified theoretical account that connects diverse experimental findings within a robust normative framework.