@inproceedings{li-etal-2026-trait,
    title = "Trait Activation in Silicon: A Situation-Aware Framework for Psychologically Grounded Role-Playing",
    author = "Li, Zuolong  and
      Wu, Pingyu  and
      Huang, Xianwen  and
      Wei, Tianyi  and
      Zhou, Wenbo",
    editor = "Liakata, Maria  and
      Moreira, Viviane P.  and
      Zhang, Jiajun  and
      Jurgens, David",
    booktitle = "Proceedings of the 64th Annual Meeting of the {A}ssociation for {C}omputational {L}inguistics (Volume 1: Long Papers)",
    month = jul,
    year = "2026",
    address = "San Diego, California, United States",
    publisher = "Association for Computational Linguistics",
    url = "https://preview.aclanthology.org/ingest-acl/2026.acl-long.1792/",
    pages = "38680--38698",
    ISBN = "979-8-89176-390-6",
    abstract = "Role-playing agents (RPAs) have made significant strides in mimicking static character identities. However, their personality simulations remain superficial, lacking a profound understanding of complex human psychological mechanisms. We identify a critical bottleneck termed ``**Personality Inertia**''{---}a behavioral rigidity where RLHF-induced alignment bias traps models in a sanitized, ``helpful assistant'' persona. This inertia prevents models from adapting to diverse social contexts or expressing essential but negative traits under pressure. To bridge this gap, we propose **PD-LLM**, a situation-aware framework grounded in *Trait Activation Theory*. PD-LLM introduces **Bipolar Latent Decomposition**, which decouples personality traits into bidirectional LoRA adapters. These adapters are dynamically modulated by a situation-aware module based on the *DIAMONDS taxonomy*, allowing for precise behavioral regulation. Empirical results show that while baseline methods fail to synchronize multidimensional traits under pressure, PD-LLM achieves superior performance in both **static fidelity** and **dynamic adaptability**. By advancing from prompt engineering to intrinsic parameter control, PD-LLM effectively overcomes personality rigidity, facilitating the creation of vivid and psychologically consistent agents."
}