CCSS International Symposium on Behavioral and Computational Social Science

15:30～15:35 Opening Remarks

Takashi KAMIHIGASHI（Director, Center for Computational Social Science, Kobe University）

15:35～15:40 Introduction

Ivan ROMIC (Center for Computational Social Science, Kobe University)

15:40～16:20

Topic

The Impact of Link-recommendation Algorithms on Opinion Polarization

Presenter

Fernando P. SANTOS (Informatics Institute, University of Amsterdam)

Abstract

Online social networks are increasingly central in shaping political opinions. While traditional media outlets are curated by humans, online social media resorts to computer algorithms to personalize contents through automatic filtering. Link recommendation algorithms (also known as social matching algorithms or people recommender systems) are implemented to recommend new connections — friends or followees — to social network users, based on supposed familiarity, similar interests, or the potential to serve as a source of useful information. These algorithms can impact network topologies. In this talk we will discuss a model to study such impacts and explore 1) How do algorithmic link recommendations interplay with opinion formation? and 2) What are the long-term impacts of such algorithms on opinion polarization? We will observe that preferentially recommending links between structurally similar nodes potentiates opinion polarisation and we will discuss avenues to steer polarisation in online social networks.

16:20～17:00

Topic

Personal Norms - and Not Only Social Norms - Shape Economic Behavior

Presenter

Zvonimir BASIC (Max Planck Institute for Research on Collective Goods)

Abstract

We propose a simple utility framework and design a novel two-part experiment to study the relevance of personal norms across various economic games and settings. We show that personal norms — together with social norms and monetary payoff — are highly predictive of individuals’ behavior. Moreover, they are: i) distinct from social norms across a series of economic contexts, ii) robust to an exogenous increase in the salience of social norms, and iii) complementary to social norms in predicting behavior. Our findings support personal norms as a key driver of economic behavior.

17:00～17:10 Short Break

17:10～17:50

Topic

The Nasty Neighbor Effect in Humans

Presenter

Angelo ROMANO (Institute of Psychology, Leiden University)

Abstract

Decades of research have shown that humans cooperate with ingroup members more than with strangers and individuals from rivaling out-groups. Such parochial cooperation is often taken as suggesting that humans also compete more between than within groups. Whereas this could explain intergroup polarization and conflict, competition is not the flip side of cooperation, and direct evidence for parochial competition is missing. I will present results of a project where we tested the hypothesis that people compete less with ingroup members than with outgroup members, and unidentified strangers.
I will discuss results from a large-scale dyadic contest experiment across 51 nations around the world (N=12,863), in a lab-in-the-field study among tribes in Kenya (N=552), and a pre-registered replication in the United Kingdom (N=401).

17:50～18:30

Topic

Cross-cultural Variation in Cooperation: A Meta-analysis

Presenter

Giuliana SPADARO (Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam)

Abstract

Impersonal cooperation enables societies to create valuable public goods, such as public services, and democracy. Several factors have been proposed to explain variation in cooperation across societies, referring to institutions, religion, cultural beliefs and values, and ecology. To date, there is no broad consensus about the extent to which there is variation in impersonal cooperation across modern societies and the institutional, cultural, and ecological factors underlying this variation. In this project, we tested 17 preregistered hypotheses in a meta-analysis of 1,506 studies of impersonal cooperation in social dilemmas conducted in 70 societies (k = 2271, N = 183,697), where people make costly decisions to cooperate with strangers. After controlling for 10 study characteristics that can affect the outcome of studies, we found very little cross-societal variation in impersonal cooperation. Categorizing societies into cultural groups explained no variance in cooperation. None of the cross-societal factors hypothesized to relate to impersonal cooperation explained variance in cooperation. We replicated these conclusions by meta-analyzing 514 studies across 41 states and 9 regions in the United States (k = 783). Thus, we observed that impersonal cooperation occurred in all societies and to a similar degree across societies suggesting that prior research may have overemphasized the magnitude of differences between modern societies in impersonal cooperation.