Behaviorally Grounded User Profiles from the Wild for Personalized Alignment and Multi-Perspective Reasoning

arXiv cs.CL Papers

Summary

This paper introduces a framework for extracting behaviorally grounded user profiles from social media posts to enhance personalized alignment and multi-perspective reasoning in large language models, outperforming synthetic profile methods.

arXiv:2609.00014v1 Announce Type: new Abstract: Persona-driven techniques increasingly adapt large language models (LLMs) to diverse contexts. However, existing methods predominantly rely on rigid, synthetic personas that flatten individual variation, rely on stereotypes, and miss the nuanced signals driving actual human preferences. We introduce profile behavioral grounding, a framework for extracting open-ended, high-fidelity user profiles directly from authentic, anonymized social media posts. We evaluate these profiles across two paradigms: train-time personalization via supervised finetuning (SFT) and non-parametric test-time multi-perspective reasoning. Across complex recommendation and open-ended query benchmarks, behaviorally grounded profiles consistently improve base models and outperform synthetic profile baselines, driving stronger parametric alignment and enabling richer, multifaceted reasoning. Our findings establish open-ended, behavior-derived profiles as a highly diverse and effective foundation for the next generation of personalized language systems. Our code base is available at https://github.com/ServiceNow/behavior-grounding.
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# Behaviorally Grounded User Profiles from the Wild for Personalized Alignment and Multi-Perspective Reasoning
Source: [https://arxiv.org/abs/2609.00014](https://arxiv.org/abs/2609.00014)
[View PDF](https://arxiv.org/pdf/2609.00014)

> Abstract:Persona\-driven techniques increasingly adapt large language models \(LLMs\) to diverse contexts\. However, existing methods predominantly rely on rigid, synthetic personas that flatten individual variation, rely on stereotypes, and miss the nuanced signals driving actual human preferences\. We introduce profile behavioral grounding, a framework for extracting open\-ended, high\-fidelity user profiles directly from authentic, anonymized social media posts\. We evaluate these profiles across two paradigms: train\-time personalization via supervised finetuning \(SFT\) and non\-parametric test\-time multi\-perspective reasoning\. Across complex recommendation and open\-ended query benchmarks, behaviorally grounded profiles consistently improve base models and outperform synthetic profile baselines, driving stronger parametric alignment and enabling richer, multifaceted reasoning\. Our findings establish open\-ended, behavior\-derived profiles as a highly diverse and effective foundation for the next generation of personalized language systems\. Our code base is available at[this https URL](https://github.com/ServiceNow/behavior-grounding)\.

## Submission history

From: Yuxuan Li \[[view email](https://arxiv.org/show-email/83fb86fe/2609.00014)\] **\[v1\]**Tue, 11 Aug 2026 10:19:11 UTC \(12,494 KB\)

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