Julia Mendelsohn

Today, social media platforms hold the sole power to study the effects of feed-ranking algorithms. We developed a platform-independent method that reranks participants’ feeds in real time and used this method to conduct a preregistered 10-day field experiment with 1256 participants on X during the 2024 US presidential campaign. Our experiment used a large language model to rerank posts that expressed antidemocratic attitudes and partisan animosity (AAPA). Decreasing or increasing AAPA exposure shifted out-party partisan animosity by more than 2 points on a 100-point feeling thermometer, with no detectable differences across party lines, providing causal evidence that exposure to AAPA content alters affective polarization. This work establishes a method to study feed algorithms without requiring platform cooperation, enabling independent evaluation of ranking interventions in naturalistic settings.

New paper in Science:

In a platform-independent field experiment, we show that reranking content expressing antidemocratic attitudes and partisan animosity in social media feeds alters affective polarization.

🧵

Postdoctoral Research Opportunity – Global LLM Values Benchmarking Working Group: Postdoctoral Affairs - Northwestern University

🚨 Postdoc opening -- Come work with us at Northwestern! 🚨 This position is to work on evaluating LLMs for sociopolitical value expression: postdocs.northwestern.edu/announcement... -- Please share!

screenshot of the title and authors of the Science paper that are linked in the next post

Our new article in @science.org enables social media reranking outside of platforms' walled gardens.

We add an LLM-powered reranking of highly polarizing political content into N=1256 participants' feeds. Downranking cools tensions with the opposite party—but upranking inflames them.

Check out @isabelcorpus.bsky.social's fantastic thread on our paper studying the effects of a "write with AI" button on change.org! ✍️ Spoiler: the effects of AI aren't always positive.

Here at UMass Amherst CICS, we’re searching for TT faculty in NLP – see the link from
www.cics.umass.edu/about/employ...

I’m happy to answer questions of course, too!

🚨New WP🚨
Dialogues with our AI DebunkBot:
✔️Reduced belief in antisemitic conspiracy theories among believers
✔️Effect durable at 1+ month
✔️Improved attitudes towards Jews among initially negative participants

🟰Debunking works for deeply rooted, identity-linked conspiracies
osf.io/preprints/ps...

Assistant Professor of Computer Sciences: Natural Language Processing (RISE-AI) - Madison, Wisconsin, United States Current Employees: If you are currently employed at any of the Universities of Wisconsin, log in to Workday to apply through the internal application process.Job Category:FacultyEmployment Type:Regula...

Wisconsin-Madison CS is recruiting faculty for natural language processing!

jobs.wisc.edu/jobs/assista...

TikTok and the likes transformed how we spend time on our phones. But do they increase mobile use, or just reshuffle what we already do?

We find that adopting TikTok increases total mobile usage and shortens breaks from the phone.

Preprint: osf.io/preprints/so...

Interested in detecting influence operations on TikTok? Check this out👇 just accepted at ICWSM 2026 @icwsm.bsky.social 🚀🚀🚀

🚨 Call for Papers!

The Polcomm Section invites submissions for #APSA2026, taking place September 3–6.

Next year’s theme is “Democracy Under Threat: How to Understand, Protect & Rebuild.”

👉 Submit now: buff.ly/PRvg2Wq

University of Birmingham photo

SAVE THE DATE! We are pleased to announce that the 8th COMPTEXT Conference will take place at the Institute of Data and AI (lnkd.in/ebN7za_Q) of the University of Birmingham, 23-25 April 2026, with @chrisguarnold.bsky.social serving as the lead local organiser. Call for Papers coming soon!

𝙒𝙚'𝙧𝙚 𝙝𝙞𝙧𝙞𝙣𝙜 𝙣𝙚𝙬 𝙛𝙖𝙘𝙪𝙡𝙩𝙮 𝙢𝙚𝙢𝙗𝙚𝙧𝙨!

KSoC: utah.peopleadmin.com/postings/190... (AI broadly)

Education + AI:
- utah.peopleadmin.com/postings/189...
- utah.peopleadmin.com/postings/190...

Computer Vision:
- utah.peopleadmin.com/postings/183...

Heading to #EMNLP2025? Interested in automatic summarization? Then come to our poster for "Unstructured Evidence Attribution for Long Context Query Focused Summarization" !

⏰ When: Fri. Nov 7 14:00-15:30
🗺️ Where: Hall C

I'm unable to attend but @iaugenstein.bsky.social will present our work!

Join Our Team — School of Data Science We are hiring faculty and staff to build a forward-thinking community with a diversity of perspectives, backgrounds, and ideas centered around data science.

Work with us at UVA School of Data Science!

@uvadatascience.bsky.social will continue to hire multiple faculty members across many areas of data science! Let me know if you're curious about our school. :)

datascience.virginia.edu/pages/join-o...

"so much depends / upon / a whitespace: Why Whitespace Matters for Poets and LLMs" by Sriharsh Bhyravajjula, Melanie Walsh, Anna Preus, Maria Antoniak

When you read a poem, do you wonder how the poet structures it through whitespace between/before words and lines?

We did! Our findings on whitespace - how to measure/preserve it, how usage varies across form/time, how it affects LLMs - now in an #EMNLP2025 (main) paper: arxiv.org/abs/2510.16713
🧵👇

Cornell (NYC and Ithaca) is recruiting AI postdocs, apply by Nov 20, 2025! If you're interested in working with me on technical approaches to responsible AI (e.g., personalization, fairness), please email me.

academicjobsonline.org/ajo/jobs/30971

A diagram illustrating pointwise scoring with a large language model (LLM). At the top is a text box containing instructions: 'You will see the text of a political advertisement about a candidate. Rate it on a scale ranging from 1 to 9, where 1 indicates a positive view of the candidate and 9 indicates a negative view of the candidate.' Below this is a green text box containing an example ad text: 'Joe Biden is going to eat your grandchildren for dinner.' An arrow points down from this text to an illustration of a computer with 'LLM' displayed on its monitor. Finally, an arrow points from the computer down to the number '9' in large teal text, representing the LLM's scoring output. This diagram demonstrates how an LLM directly assigns a numerical score to text based on given criteria

LLMs are often used for text annotation, especially in social science. In some cases, this involves placing text items on a scale: eg, 1 for liberal and 9 for conservative

There are a few ways to accomplish this task. Which work best? Our new EMNLP paper has some answers🧵
arxiv.org/pdf/2507.00828

I will be recruiting PhD students via Georgetown Linguistics this application cycle! Come join us in the PICoL (pronounced “pickle”) lab. We focus on psycholinguistics and cognitive modeling using LLMs. See the linked flyer for more details: bit.ly/3L3vcyA

A circular flow diagram that compares current and proposed practices for LLM development using data from adopters and non-adopters. Three gray boxes represent current practices: “R&D,” “Chat Models,” and “Adopters’ Needs and Usage Data,” connected in a clockwise loop with black arrows. A blue box labeled “Non-adopters’ Needs and Usage Data” adds a proposed feedback path, shown with blue arrows, linking non-adopter data back to R&D and adopters’ data.

As of June 2025, 66% of Americans have never used ChatGPT.

Our new position paper, Attention to Non-Adopters, explores why this matters: AI research is being shaped around adopters—leaving non-adopters’ needs, and key LLM research opportunities, behind.

arxiv.org/abs/2510.15951

Comparison diagram showing traditional vs discourse network user representations. Left: isolated platform-specific clusters with no cross-platform connections. Right: unified network where users are connected across platforms through shared narrative engagement, revealing previously invisible cross-platform communities.

New paper + interactive dashboard on the 2024 election information ecosystem.
Building on discourse networks work with @hanshanley.bsky.social @luceriluc.bsky.social @emilioferrara.bsky.social—this lets us visualize the online landscape as a unified system, rather than isolating each platform.

🇫🇷 We are hiring 🇫🇷

Assistant or Associate Professor Position in Computational Sociology @crestsociology.bsky.social @ipparis.bsky.social

Details here (please RT)
www.shorturl.at/E57le

Ad in the DC metro that says “AI Purpose-Built for the Department of War”

Warm greeting from the DC metro upon my return from running the NLP4Democracy workshop. 🤢

The amazing @jmendelsohn2.bsky.social kicking off the NLP4Democracy workshop!

There is one week left to apply to join us at Rutgers! We're hiring an Assistant Professor in Computational Sociology as part of a cluster of new hires in data science and AI.

Applications are due next Wednesday, 10/15.

NLP 4 Democracy - COLM 2025

I will be at #COLM2025 this week, and would love to connect with folks interested in applications (and critiques) of language modeling in social science research!

And join us for the NLP4Democracy workshop on Friday!

sites.google.com/andrew.cmu.e...

#NLP #NLProc #LLM #ComputationalSocialScience

How does online communication adapt to organizational context?

In a new pre-print with @cerenbudak.bsky.social and @lajello.bsky.social, we study US labor unions’ Facebook use of discourse frames around wins and losses in representation elections. 🧵

📖 arxiv.org/abs/2510.01757

Screenshot of paper title: Sycophantic AI Decreases Prosocial Intentions and Promotes Dependence

AI always calling your ideas “fantastic” can feel inauthentic, but what are sycophancy’s deeper harms? We find that in the common use case of seeking AI advice on interpersonal situations—specifically conflicts—sycophancy makes people feel more right & less willing to apologize.

Assistant Professor - Information - School of Information University of California, Berkeley is hiring. Apply now!

The UC Berkeley School of Information is hiring an assistant professor in the broad field of Information--including areas of info seeking/retrieval, digital humanities, cultural analytics, info viz, & philosophy of information (among others). Deadline Nov 1! aprecruit.berkeley.edu/JPF05014

Very excited that my paper with @katakeith.bsky.social is now out in @polanalysis.bsky.social. We investigate whether LLMs actually follow the instructions/definitions provided in codebooks, propose some diagnostics, and release a new evaluation dataset.
www.cambridge.org/core/journal...