Analysis of Echo Chamber Formation by Friend Recommendation
In this paper, we analyze how friend recommendation algorithms on social networks promote echo chambers. We analyze both link bias and content bias using a real social graph from X (Twitter). We extract a follow graph from X, repeatedly add new edges selected by a recommendation algorithm, and observe how the degree of bias in the graph changes. Our findings include: (1) the follow graph of X is sufficiently homophilic for recommendation algorithms to produce link bias, (2) iterated recommendations do not accelerate increase of content bias, (3) even when an algorithm recommends no user from the target user’s community, it sometimes produces link bias by recommending users from a few other communities, (4) but no similar phenomenon is observed for content bias.
doi
10.1145/3720553.3746667
isbn
979-8-4007-1534-1
name
Analysis of Echo Chamber Formation by Friend Recommendation
pages
38-42
source
bits_xml
acm_url
https://dl.acm.org/doi/10.1145/3720553.3746667
authors
Masafumi Iwanaga, Keishi Tajima
doi_url
https://doi.org/10.1145/3720553.3746667
license
CC BY 4.0
summary
In this paper, we analyze how friend recommendation algorithms on social networks promote echo chambers. We analyze both link bias and content bias using a real social graph from X (Twitter). We extract a follow graph from X, repeatedly add new edges selected by a recommendation algorithm, and observe how the degree of bias in the graph changes. Our findings include: (1) the follow graph of X is sufficiently homophilic for recommendation algorithms to produce link bias, (2) iterated recommendations do not accelerate increase of content bias, (3) even when an algorithm recommends no user from the target user’s community, it sometimes produces link bias by recommending users from a few other communities, (4) but no similar phenomenon is observed for content bias.
keywords
social network, Twitter, filter bubble, social division, polarization
published
2025-09-15
conference
HT '25: 36th ACM Conference on Hypertext and Social Media, Chicago, IL, USA, September 15-19, 2025
open_access
true
acm_html_url
https://dl.acm.org/doi/full/10.1145/3720553.3746667
ccs_concepts
Information systems → Social networking sites
displayAuthor
Masafumi Iwanaga, Keishi Tajima
proceedings_url
https://dl.acm.org/doi/proceedings/10.1145/3720553
displayPublishTime
2025-09-15
acm_reference_format
(empty)