%0 Unpublished work %T Friendship Networks and Political Opinions: A Natural Experiment among Future French Politicians %+ Département d'économie (Sciences Po) (ECON) %+ Centre pour la recherche économique et ses applications (CEPREMAP) %+ Center for Economic Policy Research (CEPR) %+ Research Institute of Industrial Economics (IFN) %A Algan, Yann %A Dalvit, Nicolò %A Do, Quoc-Anh %A Le Chapelain, Alexis %A Zenou, Yves %8 2019-06-01 %D 2019 %K Extremism %K Friendship Effect %K Homophily %K Learning %K Natural experiment %K Polarization %K Politcal opinion %K Social networks %K Extremism %Z Humanities and Social Sciences/Economics and FinancePreprints, Working Papers, ... %X We study how social interaction and friendship shape students' political opinions in a natural experiment at Sciences Po, the cradle of top French politicians. We exploit arbitrary assignments of students into short-term integration groups before their scholar cursus, and use the pairwise indicator of same-group membership as instrumental variable for friendship. After six months, friendship causes a reduction of differences in opinions by one third of the standard deviation of opinion gap. The evidence is consistent with a homophily-enforced mechanism, by which friendship causes initially politically-similar students to join political associations together, which reinforces their political similarity, without exercising an effect on initially politically-dissimilar pairs. Friendship affects opinion gaps by reducing divergence, therefore polarization and extremism, without forcing individuals' views to converge. Network characteristics also matter to the friendship effect. %G English %2 https://sciencespo.hal.science/hal-03393089/document %2 https://sciencespo.hal.science/hal-03393089/file/2019-algan-et-al-friendship-networks-and-political-opinions-a-natural-experiment-among-future-french-politicians.pdf %L hal-03393089 %U https://sciencespo.hal.science/hal-03393089 %~ SHS %~ ENS-PARIS %~ SCIENCESPO %~ CNRS %~ AO-ECONOMIE %~ OPENAIRE %~ PSL %~ USPC %~ TEST-HALCNRS %~ ENS-PSL %~ ECON-SCPO %~ SCPO_OA %~ SCPO-REPEC