Do Latent Tokens Think? A Causal and Adversarial Analysis of Chain-of-Continuous-Thought

Fuente: arXiv
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Main Authors: Zhang, Yuyi, Tang, Boyu, Ju, Tianjie, Duan, Sufeng, Liu, Gongshen
Format: Preprint
Published: 2025
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_version_ 1866918263851581440
author Zhang, Yuyi
Tang, Boyu
Ju, Tianjie
Duan, Sufeng
Liu, Gongshen
author_facet Zhang, Yuyi
Tang, Boyu
Ju, Tianjie
Duan, Sufeng
Liu, Gongshen
contents Latent tokens are gaining attention for enhancing reasoning in large language models (LLMs), yet their internal mechanisms remain unclear. This paper examines the problem from a reliability perspective, uncovering fundamental weaknesses: latent tokens function as uninterpretable placeholders rather than encoding faithful reasoning. While resistant to perturbation, they promote shortcut usage over genuine reasoning. We focus on Chain-of-Continuous-Thought (COCONUT), which claims better efficiency and stability than explicit Chain-of-Thought (CoT) while maintaining performance. We investigate this through two complementary approaches. First, steering experiments perturb specific token subsets, namely COCONUT and explicit CoT. Unlike CoT tokens, COCONUT tokens show minimal sensitivity to steering and lack reasoning-critical information. Second, shortcut experiments evaluate models under biased and out-of-distribution settings. Results on MMLU and HotpotQA demonstrate that COCONUT consistently exploits dataset artifacts, inflating benchmark performance without true reasoning. These findings reposition COCONUT as a pseudo-reasoning mechanism: it generates plausible traces that conceal shortcut dependence rather than faithfully representing reasoning processes.
format Preprint
id arxiv_https___arxiv_org_abs_2512_21711
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Do Latent Tokens Think? A Causal and Adversarial Analysis of Chain-of-Continuous-Thought
Zhang, Yuyi
Tang, Boyu
Ju, Tianjie
Duan, Sufeng
Liu, Gongshen
Computation and Language
Artificial Intelligence
I.2.7; K.6.5
Latent tokens are gaining attention for enhancing reasoning in large language models (LLMs), yet their internal mechanisms remain unclear. This paper examines the problem from a reliability perspective, uncovering fundamental weaknesses: latent tokens function as uninterpretable placeholders rather than encoding faithful reasoning. While resistant to perturbation, they promote shortcut usage over genuine reasoning. We focus on Chain-of-Continuous-Thought (COCONUT), which claims better efficiency and stability than explicit Chain-of-Thought (CoT) while maintaining performance. We investigate this through two complementary approaches. First, steering experiments perturb specific token subsets, namely COCONUT and explicit CoT. Unlike CoT tokens, COCONUT tokens show minimal sensitivity to steering and lack reasoning-critical information. Second, shortcut experiments evaluate models under biased and out-of-distribution settings. Results on MMLU and HotpotQA demonstrate that COCONUT consistently exploits dataset artifacts, inflating benchmark performance without true reasoning. These findings reposition COCONUT as a pseudo-reasoning mechanism: it generates plausible traces that conceal shortcut dependence rather than faithfully representing reasoning processes.
title Do Latent Tokens Think? A Causal and Adversarial Analysis of Chain-of-Continuous-Thought
topic Computation and Language
Artificial Intelligence
I.2.7; K.6.5
url https://arxiv.org/abs/2512.21711