TY - JOUR
T1 - Link recommendation algorithms and dynamics of polarization in online social networks
AU - Santos, Fernando P.
AU - Lelkes, Yphtach
AU - Levin, Simon A.
N1 - Funding Information:
ACKNOWLEDGMENTS. This work was supported by the James S. McDonnell Foundation 21st Century Science Initiative in Understanding Dynamic and Multi-scale Systems Postdoctoral Fellowship Award (Grant 200200555) and Collaborative Award (Grant 220020542), the National Science Foundation (Grant CCF1917819), the C3.ai Inc. and Microsoft Corporation (Award AWD1006615), and the Army Research Office (Grant W911NF-18-1-0325). We thank the College of Liberal Arts and Sciences at Arizona State University for providing the funding for the workshops that led to this paper. We thank the participants of the PNAS Political Polarization Conference, and especially Sara Constantino and Vítor Vasconcelos, for enriching comments. We also thank participants of the Theoretical Ecology Lab Tea (Department of Ecology and Evolutionary Biology, Princeton University) for useful suggestions. We thank Alan Mislove for providing us a dataset used in a previous paper (65).
Funding Information:
This work was supported by the James S. McDonnell Foundation 21st Century Science Initiative in Understanding Dynamic and Multi-scale Systems Postdoctoral Fellowship Award (Grant 200200555) and Collaborative Award (Grant 220020542), the National Science Foundation (Grant CCF1917819), the C3.ai Inc. and Microsoft Corporation (Award AWD1006615), and the Army Research Office (Grant W911NF-18-1-0325). We thank the College of Liberal Arts and Sciences at Arizona State University for providing the funding for the workshops that led to this paper. We thank the participants of the PNAS Political Polarization Conference, and especially Sara Constantino and V?tor Vasconcelos, for enriching comments. We also thank participants of the Theoretical Ecology Lab Tea (Department of Ecology and Evolutionary Biology, Princeton University) for useful suggestions. We thank Alan Mislove for providing us a dataset used in a previous paper (65).
Publisher Copyright:
© 2021 National Academy of Sciences. All rights reserved.
PY - 2021/12/14
Y1 - 2021/12/14
N2 - The level of antagonism between political groups has risen in the past years. Supporters of a given party increasingly dislike members of the opposing group and avoid intergroup interactions, leading to homophilic social networks. While new connections offline are driven largely by human decisions, new connections on online social platforms are intermediated by link recommendation algorithms, e.g., “People you may know” or “Whom to follow” suggestions. The long-term impacts of link recommendation in polarization are unclear, particularly as exposure to opposing viewpoints has a dual effect: Connections with out-group members can lead to opinion convergence and prevent group polarization or further separate opinions. Here, we provide a complex adaptive–systems perspective on the effects of link recommendation algorithms. While several models justify polarization through rewiring based on opinion similarity, here we explain it through rewiring grounded in structural similarity—defined as similarity based on network properties. We observe that preferentially establishing links with structurally similar nodes (i.e., sharing many neighbors) results in network topologies that are amenable to opinion polarization. Hence, polarization occurs not because of a desire to shield oneself from disagreeable attitudes but, instead, due to the creation of inadvertent echo chambers. When networks are composed of nodes that react differently to out-group contacts, either converging or polarizing, we find that connecting structurally dissimilar nodes moderates opinions. Overall, our study sheds light on the impacts of social-network algorithms and unveils avenues to steer dynamics of radicalization and polarization in online social networks.
AB - The level of antagonism between political groups has risen in the past years. Supporters of a given party increasingly dislike members of the opposing group and avoid intergroup interactions, leading to homophilic social networks. While new connections offline are driven largely by human decisions, new connections on online social platforms are intermediated by link recommendation algorithms, e.g., “People you may know” or “Whom to follow” suggestions. The long-term impacts of link recommendation in polarization are unclear, particularly as exposure to opposing viewpoints has a dual effect: Connections with out-group members can lead to opinion convergence and prevent group polarization or further separate opinions. Here, we provide a complex adaptive–systems perspective on the effects of link recommendation algorithms. While several models justify polarization through rewiring based on opinion similarity, here we explain it through rewiring grounded in structural similarity—defined as similarity based on network properties. We observe that preferentially establishing links with structurally similar nodes (i.e., sharing many neighbors) results in network topologies that are amenable to opinion polarization. Hence, polarization occurs not because of a desire to shield oneself from disagreeable attitudes but, instead, due to the creation of inadvertent echo chambers. When networks are composed of nodes that react differently to out-group contacts, either converging or polarizing, we find that connecting structurally dissimilar nodes moderates opinions. Overall, our study sheds light on the impacts of social-network algorithms and unveils avenues to steer dynamics of radicalization and polarization in online social networks.
KW - Complex systems
KW - Link recommendation
KW - Opinion dynamics
KW - Polarization
KW - Social networks
UR - http://www.scopus.com/inward/record.url?scp=85104360308&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85104360308&partnerID=8YFLogxK
U2 - 10.1073/pnas.2102141118
DO - 10.1073/pnas.2102141118
M3 - Article
C2 - 34876508
AN - SCOPUS:85104360308
SN - 0027-8424
VL - 118
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 50
M1 - e2102141118
ER -