Neural Synchrony Between Socially Interacting Language Models
Zhining Zhang, Wentao Zhu, Chi Han, Yizhou Wang, Heng Ji

TL;DR
This paper investigates neural synchrony between socially interacting language models as a new way to assess their social capabilities, revealing parallels with human social brain mechanisms and providing insights into LLM sociality.
Contribution
It introduces neural synchrony as a novel proxy for analyzing the social behavior of LLMs, bridging insights from neuroscience and AI.
Findings
Neural synchrony correlates with social engagement in LLMs.
Synchrony reflects temporal alignment during interactions.
Higher synchrony indicates better social performance.
Abstract
Neuroscience has uncovered a fundamental mechanism of our social nature: human brain activity becomes synchronized with others in many social contexts involving interaction. Traditionally, social minds have been regarded as an exclusive property of living beings. Although large language models (LLMs) are widely accepted as powerful approximations of human behavior, with multi-LLM system being extensively explored to enhance their capabilities, it remains controversial whether they can be meaningfully compared to human social minds. In this work, we explore neural synchrony between socially interacting LLMs as an empirical evidence for this debate. Specifically, we introduce neural synchrony during social simulations as a novel proxy for analyzing the sociality of LLMs at the representational level. Through carefully designed experiments, we demonstrate that it reliably reflects both…
Peer Reviews
Decision·ICLR 2026 Poster
S1. This work is novel in exploring whether LLMs exhibit similarity at the representation level during social interaction, and designs a new evaluation method (whether these representations can be used to predict the next behavior of the interacting agent) to examine the existence of such social minds. S2. I must say that the paper is very clearly written. This work allows readers unfamiliar with inter-brain synchrony background to easily understand the intention and existing work. The paper pr
W1. The choice of affine transformation lacks good justification (why should the relationship between representations be linear?). Although the results show this transformation is meaningful for using one LLM's representation at time t to predict another LLM's representation at time t+1, there is no theoretical explanation, nor are alternatives provided. Additionally, the explanation for why predictability can measure synchrony is incomplete. The current logic of the paper is: IBS is analogized
**S1**: This paper introduces an interesting and to me novel perspective on studying LM social capabilities through the lens of neural synchrony, rather than through behavioural outputs alone. I think that the motivation and connection with neuroscience is interesting and brings a fresh perspective. Although it may seem anthropomorphic on first glance, I do think it also makes sense to study this property in interacting LMs and the proposed metric could provide another tool for probing LMs. **
**W1**: Although I like the current ablations, I think there are still some potential issues that I can see with the setup. I think due to the strong claim (that LMs do exhibit neural synchrony), I would want to see some strong evidence ruling out alternative explanations. - **W1a**: One is that the paper states that "representations from the same interaction are not split between train and test sets", but it doesn't seem clear whether representations from the same personas in different scenar
1. This paper is the first to apply the neuroscience concept of "inter-brain synchronization" (IBS) to LLMs, which is highly innovative. 2. The experimental setup was very thorough, and the comparison results are quite convincing. The authors constructed 21 model pairs (covering two major families) and simulated 450 scenarios × 3 random seeds.
1. As the author mentioned, there is a lack of validation for larger models, such as the 14b and 32b models. 2. SOTOPIA has certain limitations, including only short-term interactions (averaging 6-8 rounds) and institutionally structured communication. 3. It is possible to explore more agents than just two, which would better simulate real-world communication scenarios. 4. The control group setup in the article still has some shortcomings; more control groups could be added to isolate scene and
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Taxonomy
TopicsAction Observation and Synchronization · Neurobiology of Language and Bilingualism · Embodied and Extended Cognition
