The False Belief Test (FBT) has been the main method for assessing Theory of Mind (ToM) and related socio-cognitive competencies. For Large Language Models (LLMs), the reliability and explanatory potential of this test have remained limited due to issues like data contamination, insufficient model details, and inconsistent controls. We address these issues by testing 17 open-weight models on a balanced set of 192 FBT variants (Trott et al., 2023) using Bayesian Logistic regression to identify how model size and post-training affect socio-cognitive competence. We find that scaling model size benefits performance, but not strictly. A cross-over effect reveals that explicating propositional attitudes (X thinks) fundamentally alters response patterns. Instruction tuning partially mitigates this effect, but further reasoning-oriented fine-tuning amplifies it. In a case study analysing social reasoning ability throughout OLMo 2 training, we show that this cross-over effect emerges during pre-training, suggesting that models acquire stereotypical response patterns tied to mental-state vocabulary that can outweigh other scenario semantics. Finally, vector steering allows us to isolate a think vector as the causal driver of observed FBT behaviour.
BanglaSocialBench: A Benchmark for Evaluating Sociopragmatic and Cultural Alignment of LLMs in Bangladeshi Social Interaction
Jahangirnagar University(贾亨吉尔纳加尔大学);Rajshahi University of Engineering & Technology(拉贾沙希工程与技术大学);Bangladesh University of Engineering and Technology(孟加拉工程与技术大学)
How Agents Represent Humans: Human-Directed Stereotypes in an Open Agent Social Network
School of Artificial Intelligence, Jilin University(吉林大学人工智能学院);Engineering Research Center of Knowledge-Driven Human-Machine Intelligence, Jilin University(吉林大学知识驱动人机智能工程研究中心);International Center of Future Science, Jilin University(吉林大学未来科学国际中心)
Reasoning that Travels: Dissecting How Chain-of-Thought Transfers Across Models
MaiNLP, Center for Information and Language Processing, LMU Munich, Germany(MaiNLP,信息与语言处理中心,慕尼黑大学,德国);Munich Center for Machine Learning, Germany(慕尼黑机器学习中心,德国)