New paper by GEIS members Ernesto and Tiago, with Natalia Aruguete and Carlos Scartascini in the Journal of Information Technology and Politics: Keep your promises, even when your peers do not: a survey experiment on the influence of social media on trust
https://doi.org/10.1080/19331681.2025.2502503
Do polarizing political tweets make us less trustworthy? Not quite. But they do make us trust others less. Our article shows how social media erodes trust — even when we stay principled.
We test how exposure to partisan tweets affects two things:
🔹 Trust — Do we believe others will keep promises?
🔹 Trustworthiness — Do we keep our own promises?
We adapt a survey experiment to run an online “trust game” with 4,700+ participants in 🇧🇷 and 🇲🇽
To make the experiment incentive-compatible, participants could win iPads by collecting votes for their chosen candidate.
They could 🗳 Vote themselves (1 ticket) or gain a larger reward if they🤝 entrust someone else to vote for them (2 tickets)
2/3 of participants were exposed to a tweet before their second decision to cast votes or entrust to others.
Tweets were:
🔵 Polarizing or not
🔵 From in-group or out-group politicians
🧪 Designed to mimic real-world political messaging.
Here’s what we found:
🧠 Trust declined after reading polarizing tweets — especially when they came from out-group politicians.
❤️ But trustworthiness stayed stable.
People still kept their promises. They just believed others wouldn’t
More important!
The effect was stronger if users engaged with the tweet (like, retweet, reply).
Passive scrolling didn’t move the needle.
👆 But active engagement amplified distrust.
Reading isn’t reacting — and reacting shapes belief
Brazil showed stronger effects than 🇲🇽 Mexico.
Why? Possibly higher political polarization, or different media ecosystems.
But the pattern held: more engagement = less trust in others.
The most important finding?
We may still act ethically even in polarized environments…
…but we assume others won’t.
So, negative social media messages increase the trust-trustworthiness gap….
