Jul 2026· Annual International ACM SIGIR Conference on Research and Development in Information Retrieval· pp. 1130-1140· 0 citations· 48 references
Computer Science
TL;DR
SNBot is proposed, a novel social bot detection framework that explicitly models the discrepancy between node self-representations and their neighborhood embeddings and consistently outperforms state-of-the-art methods.
Abstract
The proliferation of social bots poses a persistent threat to online social platforms, making accurate and efficient detection increasingly critical. Although recent graph-based methods have achieved notable progress by modeling user interactions, many of them implicitly assume neighborhood consistency and degrade in sparse, directed, and heterophilic social graphs, where a user's neighborhood may poorly reflect its own attributes. In this work, we propose SNBot, a novel social bot detection framework that explicitly models the discrepancy between node self-representations and their neighborhood embeddings. SNBot first learns unified self-representations from multi-modal user attributes through a lightweight type-aware encoding scheme. It then performs message passing on an augmented directed graph using a bidirectional aggregation mechanism, which separately captures incoming and outgoing interactions to better characterize asymmetric behaviors. By preserving and exploiting self–neighborhood representation discrepancies rather than over-smoothing them, SNBot produces more discriminative node representations. Extensive experiments on multiple real-world benchmark datasets demonstrate that SNBot consistently outperforms state-of-the-art methods.
Social bot detection is vital for protecting online platforms from misinformation and manipulation. In recent research, graph neural networks (GNNs) have emerged as a powerful approach, since they leverage relational patterns and social interactions to identify coordinated bot behaviors. However, two key challenges arise from the nature of real-world social networks: First, bots often actively interact with human users through follows, replies, and mentions, creating numerous ''heterophilous'' edges, i.e., connections between different classes. These cross-class ties disrupt the homophily assumption underlying many GNNs, causing messagepassing to propagate and amplify errors. Second, due to the high cost and time required for manual annotation, social media platforms typically contain a large proportion of unlabeled data, with only a small fraction labeled for bot detection. Unlabeled data are often underutilized, making supervision sparse. To address this, we propose OTPCL (Optimal Transport Driven Pseudo-Labeling with Contrastive Learning), a plug-in framework for GNN-based social bot detection. OTPCL first employs contrastive learning to obtain well-separated node representations. It then formulates pseudolabel assignment as an optimal transport problem, which simultaneously generates pseudo-labels and quantifies their reliability via transport scores. These scores guide two key mechanisms: selective removal of unreliable heterophilous edges to purify the graph structure, and reducing the influence of pseudo-labels with transport scores below the dynamic threshold. Extensive experiments on three widely used benchmark datasets demonstrate that OTPCL consistently improves the detection performance across six different GNN backbones, showing strong robustness and generalization in both low-labeled and fully-labeled scenarios.
Ruixuan Xu, Mengting Hu, Xinqi Yang et al.· Proceedings of the 32nd ACM...· 0 citations
Results indicate that decoupling behavioural signatures from adversarial social positioning is valuable for modern bot detection, and that combining accuracy with interpretable evidence supports deployment in real-world moderation settings.
Quang-Vinh Dang, Phuong-Lan Nguyen, Dat Le et al.· EAI Endorsed Transactions on...· 0 citations
Hierarchical Interaction MOdeling for zero-shot generalist GAD enables anomaly detection across diverse graph domains without retraining or access to target-domain supervision by modeling the evolutionary trajectories of node representations across hierarchical structural depths, thereby capturing interaction patterns that exhibit strong cross-domain stability.
Xiangping Zheng, Xuan Feng, Bo Wu et al.· Proceedings of the 32nd ACM...· 0 citations
Results highlight the value of integrating relational graph structures with complementary feature representations for misinformation detection, and provide a foundation for future extensions, including federated learning, explainability techniques, and cross-domain applications in multilingual contexts.
Gözde KARATAŞ BAYDOĞMUŞ, Onder Demir· PeerJ Computer Science· 0 citations
Graph-based social recommendation leverages both the interaction graph and the social graph to model user preferences, especially under sparse feedback. However, users' intricate social behaviors may introduce mismatched social ties that contaminate user representations and harm the models' robustness. The majority of existing methods mitigate this by pruning, rewiring, or assigning edge-wise weights before social aggregation. From users' historical behaviors, we observe that a social neighbor often overlaps with the target user on specific interests but differs in others. Thus, using a single weight for each social connection is insufficient, as it only scales the overall message intensity and fails to selectively suppress the misaligned components within the aggregated message. To fill this gap, we propose Orthogonal Decomposition for Social Recommendation (ODSR), an embedding-space framework that orthogonally decomposes the aggregated social message into an aligned component and an orthogonal deviation, and learns a dimension-wise vector gate to regulate the deviation under ranking supervision. Additionally, we introduce a contrastive regularizer that perturbs representations along deviation directions to enhance robustness against imperfect social signals. Extensive experiments on three datasets show that ODSR consistently outperforms strong baselines, and additional analyses verify the effectiveness of selectively gating the orthogonal deviation.
Rongfeng Guo, Yinxuan Huang, Wei Chen et al.· Proceedings of the 32nd ACM...· 0 citations