Yoshinobu Kawahara
2026
Timesteps of Mamba Align with Human Reading Times
Yuji Yamamoto | Shinnosuke Isono | Yoshinobu Kawahara | Sho Yokoi
Findings of the Association for Computational Linguistics: ACL 2026
Yuji Yamamoto | Shinnosuke Isono | Yoshinobu Kawahara | Sho Yokoi
Findings of the Association for Computational Linguistics: ACL 2026
This study demonstrates an alignment of per-word processing time in a popular state-space language model Mamba and human readers. In Mamba, the recurrent state transition at each layer conceptually takes some duration of time, the discretization timestep 𝛥t, determined dynamically in response to the input. Using a naturalistic reading dataset, we show that the per-word timestep from Mamba is a powerful predictor of human reading times, comparable to strong baselines such as word frequency and GPT-2 surprisal and significant even when they are controlled for. We further suggest, through formal analysis of Mamba’s architecture and internal dynamics, that Mamba can serve as a new, valuable lens to look at human real-time language processing with ever-updated memory, because it allows us to look at how each module (layer) weighs short- and long-term information retention, and how noise may interact with dynamic, continuous memory representation. Code is available via an (anonymized) link.