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Stella Li

@stellali.bsky.social
1.3K followers 197 following 66 posts

PhD student @uwnlp.bsky.social @uwcse.bsky.social | visiting researcher @MetaAI | previously @jhuclsp.bsky.social stellalisy.com

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Stella Li @stellali.bsky.social · 25/11/2025
Co-led with @pkargupta.bsky.social ✨ We learned so much and couldn't have done it w/o our amazing collaborators and mentors: Ken Wang, Jinu Lee, @shan23chen.bsky.social, @orevaahia.bsky.social, Dean Light, Tom Griffiths, @maxkw.bsky.social, Jiawei Han, @asli-celikyilmaz.bsky.social, Yulia Tsvetkov🩵
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Stella Li @stellali.bsky.social · 25/11/2025
More fun details, especially extension cognitive science background💫, in our 24-page paper! 📄Paper: arxiv.org/abs/2511.16660 💻Code: github.com/pkargupta/co... 🤗Data: huggingface.co/collections/... 🌐 Blogpost: tinyurl.com/cognitive-fo...
arxiv.org
Cognitive Foundations for Reasoning and Their Manifestation in LLMs
Large language models (LLMs) solve complex problems yet fail on simpler variants, suggesting they achieve correct outputs through mechanisms fundamentally different from human reasoning. To understand...
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Stella Li @stellali.bsky.social · 25/11/2025
What our Cognitive Foundations framework enables: 🔍 Systematic diagnosis of reasoning failures 🎯 Predicting which training→which capabilities 🧪 Testing cognitive theories at scale 🌉 Shared vocabulary bridging cognition & AI research More on opportunities & challenges in📄
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Stella Li @stellali.bsky.social · 25/11/2025
Test-time reasoning guidance: up to 66.7% improvement 💡 We scaffold cognitive structures from successful traces to guide reasoning. Major gains on ill-structured problems🌟 Models possess latent capabilities—they just don't deploy them adaptively without explicit guidance.
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Stella Li @stellali.bsky.social · 25/11/2025
🧑🏻Humans reason differently‼️ More abstraction (54% vs 36%), self-awareness (49% vs 19%), conceptual processing. Less surface enumeration and rigid sequential chaining. Even with correct answers—underlying mechanisms diverge fundamentally.
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Stella Li @stellali.bsky.social · 25/11/2025
We analyzed 1,598 LLM reasoning papers: Research concentrates on easily quantifiable behaviors—sequential organization (55%), decomposition (60%) Neglects meta-cognitive controls (8-16%) and alternative representations (10-27%) that correlate with success⚠️
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Stella Li @stellali.bsky.social · 25/11/2025
Structure matters as much as presence📐 We introduce method to extract reasoning structure from traces Successful: selective attention → knowledge alignment → forward chaining Common: skip to forward chaining LLMs prematurely seek solution before understanding constraints‼️
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Stella Li @stellali.bsky.social · 25/11/2025
Model-specific patterns reveal training impact: Olmo3 exhibits more diverse cognitive elements (49%)—they explicitly included meta-reasoning data during midtraining. DeepHermes-3: only 12% avg presence. Training methodology shapes cognitive profiles dramatically.
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Stella Li @stellali.bsky.social · 25/11/2025
Meta-cognitive deficit is severe: 🤔Self-awareness: 16% in research design, 19% in LLM traces vs 49% in humans 🧐Self-evaluation on non-verifiable problems collapses (53.5% presence, 0.031 correlation) Models can't self-assess without ground truth.
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Stella Li @stellali.bsky.social · 25/11/2025
The presence-effectiveness paradox: Logical coherence: 91% of traces, 0.091 corr. w/ success Knowledge alignment: 20% of traces, 0.234 correlation (high) Models frequently attempt core elements but fail to execute. Having the capability ≠ deploying it successfully😬
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Stella Li @stellali.bsky.social · 25/11/2025
Models deploy strategies inversely to what works 🚨 As problems become ill-structured, models narrow their repertoire—but successful traces show need for greater diversity (successful = high ppmi in fig). Sequential organization dominates. Meta-cognition disappears in LLMs.
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Stella Li @stellali.bsky.social · 25/11/2025
We analyze 192K LLM reasoning traces from 18 models (text,image,video)+LLM 54 humans think-aloud traces We introduce a framework for fine-grained span-level cognitive evaluation: WHICH elements appear, WHERE, and HOW they're sequenced. First analysis of its kind at this scale📊
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Stella Li @stellali.bsky.social · 25/11/2025
Our taxonomy bridges cognitive science → LLM eval: 28 elements across 4 dimensions—reasoning invariants (compositionality, logical coherence), meta-cognitive controls (self-awareness), representations (hierarchical, causal), and operations (backtracking, verification)
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Stella Li @stellali.bsky.social · 25/11/2025
LLMs solve hard problems but fail on easy variants, exhibit patterns different from humans. The issue: reasoning evaluations is by outcomes w/o understanding the cognitive processes that produce them. We can't diagnose failures or predict how training produces capabilities🚨
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Stella Li @stellali.bsky.social · 25/11/2025
🤔💭What even is reasoning? It's time to answer the hard questions! We built the first unified taxonomy of 28 cognitive elements underlying reasoning Spoiler—LLMs commonly employ sequential reasoning, rarely self-awareness, and often fail to use correct reasoning structures🧠
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Michael Noukhovitch @mnoukhov.bsky.social · 20/11/2025
Because Olmo 3 is fully open, we decontaminate our evals from our pretraining and midtraining data. @stellali.bsky.social proves this with spurious rewards: RL trained on a random reward signal can't improve on the evals, unlike some previous setups
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Reposted by Stella Li
Maarten Sap @maartensap.bsky.social · 06/10/2025
Day 1 (Tue Oct 7) 4:30-6:30pm, Poster Session 2 Poster #77: ALFA: Aligning LLMs to Ask Good Questions: A Case Study in Clinical Reasoning; led by @stellali.bsky.social & @jiminmun.bsky.social
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Stella Li @stellali.bsky.social · 22/07/2025
This project was done as part of the Meta FAIR AIM mentorship program. Special thanks to my amazing collaborators and awesome mentors @melaniesclar.bsky.social @jcqln_h @hunterjlang @AnsongNi @andrew_e_cohen @jacoby_xu @chan_young_park @tsvetshop.bsky.social ‪@asli-celikyilmaz.bsky.social‬ 🫶🏻💙
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Stella Li @stellali.bsky.social · 22/07/2025
✨PrefPalette🎨 bridges cognitive science, social psychology, and AI for explainable preference modeling✨ 📖Paper: arxiv.org/abs/2507.13541 💻Code: github.com/stellalisy/P... Join us in shaping interpretable AI that you can trust and control🚀Feedback welcome! #AI #Transparency
arxiv.org
PrefPalette: Personalized Preference Modeling with Latent Attributes
Personalizing AI systems requires understanding not just what users prefer, but the reasons that underlie those preferences - yet current preference models typically treat human judgment as a black bo...
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Stella Li @stellali.bsky.social · 22/07/2025
🌍Bonus: PrefPalette🎨 is a computational social science goldmine! 📊 Quantify community values at scale 📈 Track how norms evolve over time 🔍 Understand group psychology 📋 Move beyond surveys to revealed preferences
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Stella Li @stellali.bsky.social · 22/07/2025
💡Potential real-world applications: 🛡️Smart content moderation—explains why content is flagged/decisions are made 🎯Interpretable LM alignment—revealing prominent attributes ⚙️Controllable personalization—giving user agency to personalize select attributes
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Stella Li @stellali.bsky.social · 22/07/2025
🔍More importantly‼️we can see WHY preferences differ: r/AskHistorians:📚values verbosity r/RoastMe:💥values directness r/confession:❤️values empathy We visualize each group’s unique preference decisions—no more one-size-fits-all. Understand your audience at a glance🏷️
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Stella Li @stellali.bsky.social · 22/07/2025
🏆Results across 45 Reddit communities: 📈Performance boost: +46.6% vs GPT-4o 💪Outperforms other training-based baselines w/ statistical significance 🕰️Robust to temporal shifts—trained pref models can be used out-of-the box!
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Stella Li @stellali.bsky.social · 22/07/2025
⚙️How it works (pt.2) 1: 🎛️Train compact, efficient detectors for every attribute 2: 🎯Learn community-specific attribute weights during preference training 3: 🔧Add attribute embeddings to preference model for accurate & explainable predictions
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Stella Li @stellali.bsky.social · 22/07/2025
⚙️How it works (prep stage) 📜Define 19 sociolinguistics & cultural attributes from literature 🏭Novel preference data generation pipeline to isolate attributes Our data gen pipeline generates pairwise data on *any* decomposed dimension, w/ applications beyond preference modeling
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Stella Li @stellali.bsky.social · 22/07/2025
Meet PrefPalette🎨! Our approach: 🔍⚖️models preferences w/ 19 attribute detectors and dynamic, context-aware weights 🕶️👍uses unobtrusive signals from Reddit to avoid response bias 🧠mirrors attribute-mediated human judgment—so you know not just what it predicts, but *why*🧐
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Stella Li @stellali.bsky.social · 22/07/2025
🔬Cognitive science reveals how humans break choices into attributes, e.g.: 😂 Humor ❤️ Empathy 💬 Conformity ...then weight them based on context (e.g. comedy vs counseling). These traits shape every decision, from product picks to conversation tone. Your mind is a colorful palette🎨
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Stella Li @stellali.bsky.social · 22/07/2025
🚨Current preference models only output a reward/score: ❌No transparency in decision-making ❌Personalization breaks easily, one-size-fits-all scores ❌Use explicit annotations (response bias) They can’t adapt to individual tastes, can’t debug errors, and fail to build trust🙅
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Stella Li @stellali.bsky.social · 22/07/2025
WHY do you prefer something over another? Reward models treat preference as a black-box😶‍🌫️but human brains🧠decompose decisions into hidden attributes We built the first system to mirror how people really make decisions in our recent COLM paper🎨PrefPalette✨ Why it matters👉🏻🧵
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Eric Frankel @esfrankel.bsky.social · 27/02/2025
Want to quickly sample high-quality images from diffusion models, but can’t afford the time or compute to distill them? Introducing S4S, or Solving for the Solver, which learns the coefficients and discretization steps for a DM solver to improve few-NFE generation. Thread 👇 1/
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Stella Li @stellali.bsky.social · 21/02/2025
This work was jointly done with the amazing @jiminmun.bsky.social ! And huge shout out to our awesome collaborators and mentors faebrahman.bsky.social, Jonathan Ilgen, Yulia (tsvetshop.bsky.social) and maartensap.bsky.social 🩵🥰
faebrahman.bsky.social
Faeze Brahman (@faebrahman.bsky.social)
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Stella Li @stellali.bsky.social · 21/02/2025
ALFA is open-source! There are many more analyses in the paper, check them out!📖 🔗 Paper: arxiv.org/abs/2502.14860 💻 Code: github.com/stellalisy/ALFA 🤖 Data: tinyurl.com/MedicAskDocsData Join us in the effort to make LLMs better at question asking! 🚀 #Healthcare #NLProc #AI4Science
arxiv.org
Aligning LLMs to Ask Good Questions A Case Study in Clinical Reasoning
Large language models (LLMs) often fail to ask effective questions under uncertainty, making them unreliable in domains where proactive information-gathering is essential for decisionmaking. We presen...
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Stella Li @stellali.bsky.social · 21/02/2025
Why this matters for AI safety & reliability: 🛡️ Better information gathering = Better decisions✅ Proactive questioning = Fewer blind spots🧐 Structured attributes = More controllable AI🤖 Interactive systems = More natural AI assistants🫶🏻
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Stella Li @stellali.bsky.social · 21/02/2025
ALFA isn't just for medicine! The framework could be adapted to ANY field where proactive information gathering matters: Legal consultation ⚖️ Financial advising 💰 Educational tutoring 📚 Investigative journalism 🕵️ Anywhere an AI needs to ask (not just answer), you should try ALFA out!🌟
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Stella Li @stellali.bsky.social · 21/02/2025
🌟 Impressive Generalization! ALFA-trained models maintain strong performance even on completely new interactive medical tasks (MediQ-MedQA). highlighting ALFA’s potential for broader applicability in real-world clinical scenarios‼️
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Stella Li @stellali.bsky.social · 21/02/2025
🔬 Key Finding #2: Every Attribute Matters! Removing any single attribute hurts performance‼️ Grouping general (clarify, focus, answerability) vs. clinical (medical accuracy, diagnostic relevance, avoiding DDX bias) attributes leads to drastically different outputs👩‍⚕️ Check out some cool examples!👇
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Stella Li @stellali.bsky.social · 21/02/2025
🔬 Key Finding #1: Preference Learning > Supervised Learning Is it just good synthetic data❓ No❗️ Simply showing good examples isn't enough! Models need to learn directional differences between good and bad questions. (but only SFT no DPO also doesn't work!)
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Stella Li @stellali.bsky.social · 21/02/2025
Results show ALFA’s strengths🚀 ALFA-aligned models achieve: ⭐️56.6% reduction in diagnostic errors🦾 ⭐️64.4% win rate in question quality✅ ⭐️Strong generalization. in comparison with baseline SoTA instruction-tuned LLMs.
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Stella Li @stellali.bsky.social · 21/02/2025
The secret sauce of ALFA? 🔍 6 key attributes from theory (cognitive science, medicine): General: - Clarity ✨ - Focus 🎯 - Answerability 💭 Clinical: - Medical Accuracy 🏥 - Diagnostic Relevance 🔬 - Avoiding Bias ⚖️ Each attribute contributes to different aspect of the complex goal of question asking!
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Stella Li @stellali.bsky.social · 21/02/2025
📚 Exciting Dataset Release: MediQ-AskDocs! 17k real clinical interactions 80k attribute-specific question variations 302 expert-annotated scenarios Perfect for research on interactive medical AI First major dataset for training & evaluating medical question-asking! 🎯 huggingface.co/datasets/ste...
huggingface.co
stellalisy/MediQ_AskDocs_preference · Datasets at Hugging Face
We’re on a journey to advance and democratize artificial intelligence through open source and open science.
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Stella Li @stellali.bsky.social · 21/02/2025
Introducing ALFA: ALignment via Fine-grained Attributes 🎓 A systematic, general question-asking framework that: 1️⃣ Decomposes the concept of good questioning into attributes📋 2️⃣ Generates targeted attribute-specific data📚 3️⃣ Teaches LLMs through preference learning🧑‍🏫
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Stella Li @stellali.bsky.social · 21/02/2025
Why is this important?🤔 Current LLMs struggle with good question asking and proactive info-seeking. They often miss crucial details or ask vague questions. In medicine, this diverts convos away from key diagnostic evidence. We need AI that knows WHAT to ask and HOW to ask it!🎯
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Stella Li @stellali.bsky.social · 21/02/2025
Asking the right questions can make or break decisions in fields like medicine, law, and beyond✴️ Our new framework ALFA—ALignment with Fine-grained Attributes—teaches LLMs to PROACTIVE seek information through better questions through **structured rewards**🏥❓ (co-led with @jiminmun.bsky.social) 👉🏻🧵
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Julia Mendelsohn @jmendelsohn2.bsky.social · 20/02/2025
New preprint! Metaphors shape how people understand politics, but measuring them (& their real-world effects) is hard. We develop a new method to measure metaphor & use it to study dehumanizing metaphor in 400K immigration tweets Link: bit.ly/4i3PGm3 #NLP #NLProc #polisky #polcom #compsocialsci 🐦🐦
Screenshot of top half of first page of paper. The paper is titled: "When People are Floods: Analyzing Dehumanizing Metaphors in Immigration Discourse with Large Language Models". The authors are Julia Mendelsohn (University of Chicago) and Ceren Budak (University of Michigan). The top right corner contains a visual showing the sentence "They want immigrants to pour into and infest this country". The caption says: Figure 1: Dehumanizing sentence likening immigrants to the source domain concepts of Water and Vermin via the words "pour" and "infest". 

The abstract text on the left reads: Metaphor, discussing one concept in terms of another, is abundant in politics and can shape how people understand important issues. We develop a computational approach to measure metaphorical language, focusing on immigration discourse on social media. Grounded in qualitative social science research, we identify seven concepts evoked in immigration discourse (e.g. "water" or "vermin"). We propose and evaluate a novel technique that leverages both word-level and document-level signals to measure metaphor with respect to these concepts. We then study the relationship between metaphor, political ideology, and user engagement in 400K US tweets about immigration. While conservatives tend to use dehumanizing metaphors more than liberals, this effect varies widely across concepts. Moreover, creature-related metaphor is associated with more retweets, especially for liberal authors. Our work highlights the potential for computational methods to complement qualitative approaches in understanding subtle and implicit language in political discourse.
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Stella Li @stellali.bsky.social · 20/12/2024
The feeling when you thought you were scooped from the title and the abstract but then unscooped after reading the actual paper is my best christmas present🤌💕🎁
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Neil Renic @ncrenic.bsky.social · 10/12/2024
Just had an idea
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Stella Li @stellali.bsky.social · 10/12/2024
Excited to present MediQ at #NeurIPS ! 📍Stop by my poster: East Exhibit Hall A-C #4805📷 🕚Thu, Dec 12 | 11am–2pm 🗓️tinyurl.com/mediq2024 Love to chat about anything--reasoning, synthetic data, multi-agent interaction, multilingual nlp! Message me if you want to chat☕️🍵🧋
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Stella Li @stellali.bsky.social · 07/12/2024
Thanks for sharing the work! Let me know if you have any questions!
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Stella Li @stellali.bsky.social · 06/12/2024
Huge shout out to my amazing collaborators and mentors @shangbinfeng.bsky.social @vidhishab.bsky.social @emmapierson.bsky.social @pangwei.bsky.social and Yulia (@tsvetshop.bsky.social)🥰 Literally couldn’t have done this project without you guys🫶💕
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Stella Li @stellali.bsky.social · 06/12/2024
What’s next for #MediQ? We are exploring ways to further improve uncertainty quantification and also asking better questions🤩 Explore our datasets, benchmarks, and full paper to advance interactive clinical reasoning with LLMs: arxiv.org/abs/2406.00922 💻📄
arxiv.org
MediQ: Question-Asking LLMs and a Benchmark for Reliable Interactive Clinical Reasoning
Users typically engage with LLMs interactively, yet most existing benchmarks evaluate them in a static, single-turn format, posing reliability concerns in interactive scenarios. We identify a key obst...
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