Read the full paper in Nature:
www.nature.com/articles/s41...
With @pinchofdata.bsky.social, Roland Hodler, and Ekaterina Zhuravskaya
@pse.bsky.social @bocconi.bsky.social @unisg.ch
We ran this experiment independently: no platform cooperation, no corporate funding. Instead, it was funded by the Swiss National Science Foundation SNSF.
Important nuances: the algorithm did NOT change party identification or affective polarization over the seven-week study period. It shifted policy views and attitudes on current events, not deep partisan identity.
This is a behavioral lock-in: once you follow new accounts promoted by the algorithm, they stay in your feed regardless of which feed setting you use.
Why this asymmetry? We also found that X's algorithm promotes political activist accounts (especially conservative ones) and demotes traditional news media. In response to algorithm exposure, users follow these accounts and continue to follow them even after switching to the chronological feed.
But here's the twist: switching the algorithm OFF did not reverse the effects. Users who went from algorithmic to chronological feeds showed no significant change in political attitudes. The effects of algorithm exposure are sticky.
The key finding is that switching from a chronological to an algorithmic feed shifted users toward more conservative positions: policy priorities, views on Trump’s criminal investigations, and attitudes toward the war in Ukraine all shifted to the right.
We recruited ~5,000 active X users in the US and randomly assigned them to use either the algorithmic feed ("For You") or the chronological feed ("Following") for seven weeks in summer 2023. We measured their political attitudes before and after with surveys.
Can feed algorithms shape what people think about politics? Our paper "The Political Effects of X's Feed Algorithm" is out today in Nature and answers "Yes."
www.nature.com/articles/s41...
📖 New #PolicyBrief! "Supply Chains, Trade and Economic Fragility" by Sandra Poncet.
Within the framework of the Globalization Chair.
www.parisschoolofeconomics.eu/en/publicati...
📢 Applications are open for the EP Master!
🔍 A unique program at the intersection of economics & psychology
📅 Apply now before March 12, 2026:
🔸 Psychology track: MonMaster
🔸 Economics track: E-candidat
🔗 shorturl.at/O4zJS
#FridayReading 📚
A historical and quantitative analysis of capital accumulation in Paris over two centuries, examining wealth, inequality, and public intervention in the capital by Gilles Postel-Vinay, PSE Emeritus Professor, & Jean-Laurent Rosenthal.
➡️ www.parisschoolofeconomics.eu/en/news/le-c...
📖 New #PolicyBrief! "Digitization and trade patterns" by Ariell Reshef.
Within the framework of the Globalization Chair.
shorturl.at/7m875
1/ Big news! Today, we officially launch the International Tax Observatory (#ITO)🚀
Building on the foundation of the EUTO, we are expanding our mission to address global tax evasion, wealth concentration, illicit financial flows & the intersection of taxation & the environment.
🏆 François Bourguignon, former Director of PSE and Director of Studies at @ehess.fr, has been awarded the 2026 Revue économique Prize for his major contributions to research on inequality, poverty, and economic development.
shorturl.at/LT8F8
👩🎓Best wishes to Alice Chiocchetti (@pse.bsky.social @ehess.fr) who will defend on Wednesday her thesis entitled "Essays on the Taxation of Multinational Corporations" under the supervision of Gabriel Zucman 🍀
www.parisschoolofeconomics.eu/en/persons/a...
🧑🎓Best wishes to Nagui Bechichi ( @pse.bsky.social @ehess.fr) who will defend on Wednesday his thesis under the supervision of Julien Grenet 🍀
www.parisschoolofeconomics.eu/en/persons/n...
🎓 Join a world-class program in sustainability & policy.
Together, ENPC & PSE combine their expertise to offer the MSc Sustainable Impact Analysis (SIA), a unique program at the intersection of economics, sustainability & public action.
🔗 Apply now: www.parisschoolofeconomics.eu/en/teaching/...
Make this summer count! 🌞
The PSE Summer School offers:
✅ Advanced courses with top economists
✅ An international, inspiring environment
✅ A transformative experience in Paris
📝 Apply now — limited seats available! www.parisschoolofeconomics.eu/en/summer-sc...
#PSESummerSchool #Economics #Paris
👩🎓Best wishes to Olivier Savrimoutoo (@pse.bsky.social @sorbonneparis1.bsky.social) who will defend on Monday his thesis entitled "Information Processing and Discrimination in the Lab" under the supervision of Nicolas Jacquemet 🍀
www.parisschoolofeconomics.eu/en/persons/f...
🎓 Interested in the MSc Sustainable Impact Analysis (SIA)?
The selection process is clear, fast, and transparent — from application review to interview and final decision.
🔗 Learn more & apply: www.parisschoolofeconomics.eu/en/teaching/...
#ImpactAnalysis #Education #MasterOfScience
🚀 Applications are open for the APE & PPD Masters at PSE!
🎓 APE: Master economic analysis & policy-making
🎓 PPD: Evaluate & design impactful public policies
📅 Apply before March 12, 2026!
🔗 www.pse-application.eu/
#Economics #HigherEducation #Masters
📣 Applications are now open for PSE Summer School !
💡Looking for an opportunity to enrich your economic skills and benefit from a unique combination of cutting-edge research and advanced original methods with an international dimension?
🔗 shorturl.at/fJqeF
Congratulations to @adrien-fabre.bsky.social (APE 2016, PhD 2020) awarded the 2025 @banquedefrance-off.bsky.social Prize for Young Researchers in Green Finance for his research in climate economics and sustainable finance with Thomas Giroux.
👉 Read more: shorturl.at/87gsM
📅 Join the 4th PSE-CEPR Policy Forum on Globalization at the Crossroads – June 18 and 19, 2026, in Paris.
With sessions on Internationale Trade in Turbulent Time & the Future of the International Monetary System.
🔗 shorturl.at/NrkBZ
@cepr.org #PSECEPR #Globalization #Event
@guglielmozappala.bsky.social (APE 2020, PhD 2023) has received the inaugural Allianz Trade Award for his research on how heat shocks move through global supply chains.
Read more 👇 www.parisschoolofeconomics.eu/en/news/gugl...
👩🎓Best wishes to Eustache Elina (@pse.bsky.social @sorbonneparis1.bsky.social) who will defend on Monday his thesis entitled "Three Essays on Permanent Labor Income Inequality" under the supervision of Tobias Broer and Axelle Ferrière 🍀
www.parisschoolofeconomics.eu/en/persons/e...
Congratulations to @leonard-bocquet.bsky.social (APE 2019, PhD 2024), co-winner of the 2025 Philippe Martin Award (@caeeco.bsky.social ) with Maddalena Conte. His dissertation sheds new light on how workers adapt to technological shocks and where policy can help.
shorturl.at/RwI71
It is with deep sadness that the Paris School of Economics community and the academic world have learned of the passing of Roger Guesnerie, its founding president.
His intellectual legacy will continue to inspire the academic community.
