Revisiting Early Detection of Sexual Predators via Turn-level Optimization

JinMyeong An, Sangwon Ryu, Heejin Do, Yunsu Kim, Jungseul Ok, Gary Lee


Abstract
Online grooming is a severe social threat where sexual predators gradually entrap child victims with subtle and gradual manipulation. Therefore, timely intervention for online grooming is critical for proactive protection. However, previous methods fail to determine the optimal intervention points (i.e., jump to conclusions) as they rely on chat-level risk labels by causing weak supervision of risky utterances. For timely detection, we propose speed control reinforcement learning (SCoRL), incorporating a practical strategy derived from luring communication theory (LCT). To capture the predator’s turn-level entrapment, we use a turn-level risk label based on the LCT. Then, we design a novel speed control reward function that balances the trade-off between speed and accuracy based on turn-level risk label; thus, SCoRL can identify the optimal intervention moment. In addition, we introduce a turn-level metric for precise evaluation, identifying limitations in previously used chat-level metrics. Experimental results show that SCoRL effectively preempted online grooming, offering a more proactive and timely solution. Further analysis reveals that our method enhances performance while intuitively identifying optimal early intervention points.
Anthology ID:
2025.naacl-long.241
Volume:
Proceedings of the 2025 Conference of the Nations of the Americas Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 1: Long Papers)
Month:
April
Year:
2025
Address:
Albuquerque, New Mexico
Editors:
Luis Chiruzzo, Alan Ritter, Lu Wang
Venue:
NAACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
4713–4724
Language:
URL:
https://preview.aclanthology.org/fix-sig-urls/2025.naacl-long.241/
DOI:
Bibkey:
Cite (ACL):
JinMyeong An, Sangwon Ryu, Heejin Do, Yunsu Kim, Jungseul Ok, and Gary Lee. 2025. Revisiting Early Detection of Sexual Predators via Turn-level Optimization. In Proceedings of the 2025 Conference of the Nations of the Americas Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 1: Long Papers), pages 4713–4724, Albuquerque, New Mexico. Association for Computational Linguistics.
Cite (Informal):
Revisiting Early Detection of Sexual Predators via Turn-level Optimization (An et al., NAACL 2025)
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PDF:
https://preview.aclanthology.org/fix-sig-urls/2025.naacl-long.241.pdf