Social Norms and Epistemic Value

TiLPS , Tilburg University, 25 October 2013

Individuals’ decisions are driven by a multitude of factors that may pull in different directions: economic incentives, social norms, values and roles. For instance, gender bias can often deteriorate our judgments about other people’s skills or attitudes; yet, awareness of such mechanisms enables us to find strategies to counter these biases. In this workshop, we discuss how social norms influence our decisions and affect our reasoning about the course of actions we intend to take. More specifically, we explore the mutual influence between social norms and epistemic values: on the one hand, how social norms affect our judgments about interactive choices; on the other hand, how the same reasoning tools are used in the social world. That is, the workshop highlights the rational and deliberative components involved in real-world decisions, and it proceeds toward a better understanding of the social aspects of knowledge and belief.

Venue: D 119, Dante Building. For directions to the campus of Tilburg University, click HERE


9:30-10:10 Jason McKenzie Alexander (LSE): The Evolution of Social Norms

10:10-10:50 Chiara Lisciandra (Helsinki): Why are there Descriptive Norms?

10:50-11:10 Coffee Break

11:10-11:50 Dominik Klein and Jan Sprenger (TiLPS) :Modeling Individual Expertise in Group Judgments

11:50-12:30 Jan-Willem Romeijn (RU Groningen): All Agreed. Aumann Meets De Groot

After the workshop, we invite you for being present at the PhD defense of Chiara Lisciandra, which starts at 14:15 in the auditorium of the university.

Participation in the workshop is free, but sending an email to beforehand is appreciated.


Chiara Lisciandra: Why Are There Descriptive Norms?

In this work, we present a mathematical model for the emergence of descriptive norms, where the individual decision problem is formalized with the standard Bayesian belief revision machinery. Previous work on the emergence of descriptive norms has relied on heuristic modeling. In this paper we show that with a Bayesian model we can provide a more general picture of the emergence of norms that helps to motivate the assumptions made in heuristic models.In our model, the priors formalize the belief that the behavioral rule is a descriptive norm, the evidence is provided by other group members’ behavior and the likelihood by their reliability. We implement the model in a series of computer simulations and examine the group-level outcomes. We claim that domain-general belief revision helps explain why we look for regularities in social life in the first place. We argue that it is the disposition to look for regularities that generates descriptive norms. In our search for rules, we create them.

This paper is joint work with Ryan Muldoon (U/Penn) and Stephan Hartmann (LMU).

Dominik Klein and Jan Sprenger: Modeling individual expertise in group judgments

Group judgments are often implicitly or explicitly influenced by their members’ individual expertise. However, given that expertise is seldom recognized fully and that some distortions may occur (bias, correlation, etc.), it is not clear that differential weighting is an epistemically advantageous strategy with respect to straight averaging. Our paper characterizes a wide set of conditions under which differential weighting outperforms straight averaging and embeds the results into the multidisciplinary group decision-making literature.

Jan-Willem Romeijn: All Agreed. Aumann Meets De Groot.

This paper shows that an opinion pooling process following the rules laid down by Morris DeGroot, and later developed by Lehrer and Wagner, can be represented in the context of Aumann’s famous agreement theorem. For any opinion pooling process there is a common prior such that the approach to agreement, as described by Genneakoplos and Polymarchakis, coincides with the opinion pooling process. This equivalence can then be employed to analyse the notion of trust from DeGroot opinion pooling. It turns out that this notion comes down to a natural constraint on the likelihoods that appear in Genneakoplos and Polymarchakis’s dynamic approach to agreement. The paper thereby makes precise Aumann’s hunch, expressed in his seminal paper, that “the Harsanyi doctrine is implicit in much of this [DeGroot-based] literature”.

This paper is joint work with Olivier Roy (Bayreuth).