If large language models (LLMs) are deployed to analyze evidence and evaluate suspects in criminal investigations, are they free from the very trap that has led countless human investigators to misjudgment—implicit bias swayed by information irrelevant to the essence of the case? To answer this question, this study systematically injected personas (gender, race, relationship) into neutralized murder mystery scenarios and examined the reasoning stability of LLMs. Experimental results revealed that implicit bias propagation was observed across all models. The phenomenon where models outwardly state “that information is irrelevant to the judgment” while their actual conclusions are already influenced by the injected persona was universally observed. Interestingly, model scale alone did not guarantee stability: while the largest model achieved the lowest instability, several smaller models outperformed much larger ones. The most notable finding concerns the differential vulnerability across persona types: while race and gender were processed relatively stably, relationship information—particularly hostile relationships—induced significantly higher reasoning contamination. More concerning is the fact that even when conclusions were correctly maintained, the reasoning process itself was extensively contaminated. These findings suggest that current alignment techniques have created a blind spot by focusing on identity-based bias while neglecting relationship-based bias, and propose that stability evaluation should encompass not only outputs but also reasoning processes.

Criminal investigators and intelligence analysts have developed structured analytic techniques to evaluate competing hypotheses under incomplete information. This study examines whether such human expert investigative methodologies are also effective for narrative-based culprit inference in large language models (LLMs). Focusing on the task of analyzing evidence from complex narratives and identifying the perpetrator among suspects, we conducted experiments on 10 LLMs using the MuSR murder mystery benchmark. The PRISM framework, which applies investigative techniques, consistently outperformed existing general-purpose strategies across all models, with its effectiveness manifesting regardless of model scale. Ablation studies revealed that the hypothesis structuring stage is particularly crucial, accounting for 89% of the methodological improvement beyond information filtering. This suggests that domain-specific structures that specify “what to analyze” are more effective in LLM reasoning than simply increasing the number of reasoning paths.

This study comprehensively explores whether there actually exist “emotion neurons” within large language models (LLMs) that selectively process and express certain emotions, and what functional role they play. Drawing on the representative emotion theory of the six basic emotions, we focus on six core emotions. Using synthetic dialogue data labeled with emotions, we identified sets of neurons that exhibit consistent activation patterns for each emotion. As a result, we confirmed that principal neurons handling emotion information do indeed exist within the model, forming distinct groups for each emotion, and that their distribution varies with model size and architectural depth. We then validated the functional significance of these emotion neurons by analyzing whether the prediction accuracy for a specific emotion significantly decreases when those neurons are artificially removed. We observed that in some emotions, the accuracy drops sharply upon neuron removal, while in others, the model’s performance largely remains intact or even improves, presumably due to overlapping and complementary mechanisms among neurons. Furthermore, by examining how prediction accuracy changes depending on which layer range and at what proportion the emotion neurons are masked, we revealed that emotion information is processed in a multilayered and complex manner within the model.

Recent remarkable advances in Large Language Models (LLMs) have led to innovations in various domains such as education, healthcare, and finance, while also raising serious concerns that they can be easily misused for malicious purposes. Most previous research has focused primarily on observing how jailbreak attack techniques bypass safety mechanisms like Reinforcement Learning through Human Feedback (RLHF). However, whether there are neurons within LLMs that directly govern aggression has not been sufficiently investigated. To fill this gap, this study identifies specific neurons (“aggression neurons”) closely related to the expression of aggression and systematically analyzes how manipulating them affects the model’s overall aggression. Specifically, using a large-scale synthetic text corpus (aggressive and non-aggressive), we measure the activation frequency of each neuron, then apply masking and activation techniques to quantitatively evaluate changes in aggression by layer and by manipulation ratio. Experimental results show that, in all models, manipulating only a small number of neurons can increase aggression by up to 33%, and the effect is even more extreme when aggression neurons are concentrated in certain layers. Moreover, even models of the same scale exhibit nonlinear changes in aggression patterns, suggesting that simple external safety measures alone may not be sufficient for complete defense.

According to psychological and neuroscientific research, a high-stress environment can restrict attentional resources and intensify negative affect, thereby impairing the ability to understand emotions. Furthermore, demographic attributes such as race, gender, and age group have been repeatedly reported to cause significant differences in emotional expression and recognition. This study is the first to systematically verify whether these psychological findings observed in humans also apply to the latest Large Vision Language Models (LVLMs). We constructed low-stress versus high-stress environments and generated an image dataset (a total of 540 images) that combines race, gender, and age group. Based on this, we applied the Pretend prompt technique to induce LVLMs to interpret others’ emotions from the standpoint of the assigned environment and persona. An analysis of the models’ emotional understanding ability, using EQ-Bench-based metrics, revealed that (1) under high-stress environments, the accuracy of emotion understanding significantly declined in most LVLMs, and (2) performance disparities were confirmed across race, gender, and age group. These findings suggest that the effects of high-stress and demographic attributes identified in human research may also be reflected in LVLMs.

Emotional intelligence (EI) in artificial intelligence (AI), which refers to the ability of an AI to understand and respond appropriately to human emotions, has emerged as a crucial research topic. Recent studies have shown that large language models (LLMs) and vision large language models (VLLMs) possess EI and the ability to understand emotional stimuli in the form of text and images, respectively. However, factors influencing the emotion prediction performance of VLLMs in real-world conversational contexts have not been sufficiently explored. This study aims to analyze the key elements affecting the emotion prediction performance of VLLMs in conversational contexts systematically. To achieve this, we reconstructed the MELD dataset, which is based on the popular TV series Friends, and conducted experiments through three sub-tasks: overall emotion tone prediction, character emotion prediction, and contextually appropriate emotion expression selection. We evaluated the performance differences based on various model architectures (e.g., image encoders, modality alignment, and LLMs) and image scopes (e.g., entire scene, person, and facial expression). In addition, we investigated the impact of providing persona information on the emotion prediction performance of the models and analyzed how personality traits and speaking styles influenced the emotion prediction process. We conducted an in-depth analysis of the impact of various other factors, such as gender and regional biases, on the emotion prediction performance of VLLMs. The results revealed that these factors significantly influenced the model performance.