Maximilian Puelma Touzel

Large language models (LLMs) offer promising capabilities for simulating social media dynamics at scale, enabling studies that would be ethi… (voir plus)cally or logistically challenging with human subjects. However, the field lacks standardized data resources for fine-tuning and evaluating LLMs as realistic social media agents. We address this gap by introducing SIMPACT, the SIMulation-oriented Persona and Action Capture Toolkit, a privacy respecting framework for constructing behaviorally-grounded social media datasets suitable for training agent models. We formulate next-action prediction as a task for training and evaluating LLM-based agents and introduce metrics at both the cluster and population levels to assess behavioral fidelity and stylistic realism. As a concrete implementation, we release BluePrint, a large-scale dataset built from public Bluesky data focused on political discourse. BluePrint clusters anonymized users into personas of aggregated behaviours, capturing authentic engagement patterns while safeguarding privacy through pseudonymization and removal of personally identifiable information. The dataset includes a sizable action set of 12 social media interaction types (likes, replies, reposts, etc.), each instance tied to the posting activity preceding it. This supports the development of agents that use context-dependence, not only in the language, but also in the interaction behaviours of social media to model social media users. By standardizing data and evaluation protocols, SIMPACT provides a foundation for advancing rigorous, ethically responsible social media simulations. BluePrint serves as both an evaluation benchmark for political discourse modeling and a template for building domain specific datasets to study challenges such as misinformation and polarization.

2025-09-27

ArXiv (prépublication)

$\texttt{BluePrint}$: A Social Media User Dataset for LLM Persona Evaluation and Training

Aur'elien Buck-Kaeffer

Je Qin Chooi

Dan Zhao

Large language models (LLMs) offer promising capabilities for simulating social media dynamics at scale, enabling studies that would be ethi… (voir plus)cally or logistically challenging with human subjects. However, the field lacks standardized data resources for fine-tuning and evaluating LLMs as realistic social media agents. We address this gap by introducing SIMPACT, the SIMulation-oriented Persona and Action Capture Toolkit, a privacy respecting framework for constructing behaviorally-grounded social media datasets suitable for training agent models. We formulate next-action prediction as a task for training and evaluating LLM-based agents and introduce metrics at both the cluster and population levels to assess behavioral fidelity and stylistic realism. As a concrete implementation, we release BluePrint, a large-scale dataset built from public Bluesky data focused on political discourse. BluePrint clusters anonymized users into personas of aggregated behaviours, capturing authentic engagement patterns while safeguarding privacy through pseudonymization and removal of personally identifiable information. The dataset includes a sizable action set of 12 social media interaction types (likes, replies, reposts, etc.), each instance tied to the posting activity preceding it. This supports the development of agents that use context-dependence, not only in the language, but also in the interaction behaviours of social media to model social media users. By standardizing data and evaluation protocols, SIMPACT provides a foundation for advancing rigorous, ethically responsible social media simulations. BluePrint serves as both an evaluation benchmark for political discourse modeling and a template for building domain specific datasets to study challenges such as misinformation and polarization.

2025-09-27

ArXiv (prépublication)

SandboxSocial: A Sandbox for Social Media Using Multimodal AI Agents

Gayatri K

Busra Tugce Gurbuz

Austin Welch

Hao Yu

Ethan Kosak-Hine

Tom Gibbs

Dan Zhao

The online information ecosystem enables influence campaigns of unprecedented scale and impact. We urgently need empirically grounded approa… (voir plus)ches to counter the growing threat of malicious campaigns, now amplified by generative AI. But, developing defenses in real-world settings is impractical. Social system simulations with agents modelled using Large Language Models (LLMs) are a promising alternative approach and a growing area of research. However, existing simulators lack features needed to capture the complex information-sharing dynamics of platform-based social networks. To bridge this gap, we present SandboxSocial, a new simulator that includes several key innovations, mainly: (1) a virtual social media platform (modelled as Mastodon and mirrored in an actual Mastodon server) that enables a realistic setting in which agents interact; (2) an adapter that uses real-world user data to create more grounded agents and social media content; and (3) multi-modal capabilities that enable our agents to interact using both text and images---just as humans do on social media. We make the simulator more useful to researchers by providing measurement and analysis tools that track simulation dynamics and compute evaluation metrics to compare experimental results.

2025-08-16

Proceedings of the Thirty-Fourth International Joint Conference on Artificial Intelligence (publié)

SandboxSocial: A Sandbox for Social Media Using Multimodal AI Agents

Gayatri Krishnakumar

Busra Tugce Gurbuz

Austin Welch

Hao Yu

Ethan Kosak-Hine

Tom Gibbs

Dan Zhao

2025-08-16

Proceedings of the Thirty-Fourth International Joint Conference on Artificial Intelligence (publié)

Veracity: An Open-Source AI Fact-Checking System

Taylor Lynn Curtis

William Garneau

Manon Gruaz

Mike Pinder

Li Wei Wang

Sukanya Krishna

Luda Cohen

The proliferation of misinformation poses a significant threat to society, exacerbated by the capabilities of generative AI. This demo paper… (voir plus) introduces Veracity, an open-source AI system designed to empower individuals to combat misinformation through transparent and accessible fact-checking. Veracity leverages the synergy between Large Language Models (LLMs) and web retrieval agents to analyze user-submitted claims and provide grounded veracity assessments with intuitive explanations. Key features include multilingual support, numerical scoring of claim veracity, and an interactive interface inspired by familiar messaging applications. This paper will showcase Veracity's ability to not only detect misinformation but also explain its reasoning, fostering media literacy and promoting a more informed society.

2025-08-16

Proceedings of the Thirty-Fourth International Joint Conference on Artificial Intelligence (publié)

Veracity: An Open-Source AI Fact-Checking System.

Taylor Lynn Curtis

William Garneau

Manon Gruaz

Mike Pinder

Li Wei Wang

Sukanya Krishna

Luda Cohen

2025-08-16

Proceedings of the Thirty-Fourth International Joint Conference on Artificial Intelligence (publié)

TRUTH: Teaching LLMs to Rerank for Truth in Misinformation Detection

Hao Yu

Shenyang Huang

2025-07-25

colmweb.org/COLM/2025/Workshop/SoLaR (poster)

openreview.net

TRUTH: Teaching LLMs to Rerank for Truth in Misinformation Detection

Hao Yu

Shenyang Huang

Misinformation detection presents a significant challenge due to its knowledge-intensive and reasoning-intensive nature. While Retrieval-Aug… (voir plus)mented Generation (RAG) systems offer a promising direction, the effectiveness of their retrieval and reranking components is crucial. This paper introduces TRUTH, a novel reranking approach designed for domain adaptation, specifically for misinformation detection, which employs a two-stage training methodology: Supervised Fine-Tuning (SFT) and Direct Preference Optimization (DPO). We demonstrate that our 1B parameter TRUTH model achieves strong performance comparable to 7B models on established misinformation benchmarks such as FEVER and Canadian bilingual news datasets, improving retrieval quality and positively impacting downstream task accuracy. Our findings highlight the efficacy of combining SFT for broad knowledge acquisition and domain adaptation with DPO for nuanced reasoning alignment in developing efficient and effective rerankers for complex, knowledge-intensive tasks. Datasets and code will be available with the camera-ready version of the paper.

2025-07-25

colmweb.org/COLM/2025/Workshop/SoLaR (poster)

openreview.net

Veracity: An Open-Source AI Fact-Checking System

Taylor Lynn Curtis

William Garneau

Manon Gruaz

Mike Pinder

Li Wei Wang

Sukanya Krishna

Luda Cohen

The proliferation of misinformation poses a significant threat to society, exacerbated by the capabilities of generative AI. This demo paper… (voir plus) introduces Veracity, an open-source AI system designed to empower individuals to combat misinformation through transparent and accessible fact-checking. Veracity leverages the synergy between Large Language Models (LLMs) and web retrieval agents to analyze user-submitted claims and provide grounded veracity assessments with intuitive explanations. Key features include multilingual support, numerical scoring of claim veracity, and an interactive interface inspired by familiar messaging applications. This paper will showcase Veracity's ability to not only detect misinformation but also explain its reasoning, fostering media literacy and promoting a more informed society.

2025-06-18

ArXiv (prépublication)

A Simulation System Towards Solving Societal-Scale Manipulation

Austin Welch

Gayatri Krishnakumar

Dan Zhao

Hao Yu

Ethan Kosak-Hine

Tom Gibbs

Busra Tugce Gurbuz

The rise of AI-driven manipulation poses significant risks to societal trust and democratic processes. Yet, studying these effects in real-w… (voir plus)orld settings at scale is ethically and logistically impractical, highlighting a need for simulation tools that can model these dynamics in controlled settings to enable experimentation with possible defenses. We present a simulation environment designed to address this. We elaborate upon the Concordia framework that simulates offline, `real life' activity by adding online interactions to the simulation through social media with the integration of a Mastodon server. We improve simulation efficiency and information flow, and add a set of measurement tools, particularly longitudinal surveys. We demonstrate the simulator with a tailored example in which we track agents' political positions and show how partisan manipulation of agents can affect election results.

2024-10-17

ArXiv (prépublication)

A Simulation System Towards Solving Societal-Scale Manipulation

Austin Welch

Gayatri K

Dan Zhao

Hao Yu

Ethan Kosak-Hine

Tom Gibbs

Busra Tugce Gurbuz

The rise of AI-driven manipulation poses significant risks to societal trust and democratic processes. Yet, studying these effects in real-w… (voir plus)orld settings at scale is ethically and logistically impractical, highlighting a need for simulation tools that can model these dynamics in controlled settings to enable experimentation with possible defenses. We present a simulation environment designed to address this. We elaborate upon the Concordia framework that simulates offline, `real life' activity by adding online interactions to the simulation through social media with the integration of a Mastodon server. We improve simulation efficiency and information flow, and add a set of measurement tools, particularly longitudinal surveys. We demonstrate the simulator with a tailored example in which we track agents' political positions and show how partisan manipulation of agents can affect election results.

2024-10-17

ArXiv (prépublication)

Simulation System Towards Solving Societal-Scale Manipulation

Austin Welch

Gayatri K

Dan Zhao

Hao Yu

Tom Gibbs

Ethan Kosak-Hine

Busra Tugce Gurbuz