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Thinking tokens

Give a model extra tokens for computation, such as pauses, filler symbols, or learned planning tokens. These tokens need not spell out the solution.

For example: A model processes several pause tokens before answering a math question. Those extra positions let it perform additional computation, even though they do not display a worked solution.

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How the methods connect and differ

Pausing and planning

Pause tokens add computation before the answer without choosing a different plan token for each step. Planning tokens instead select a learned token before generating each written reasoning step. The latter still produces a textual chain of thought. In the pause-token experiments, the training setup matters: gains were strongest when pauses were used in both pretraining and fine-tuning, not simply inserted into an unchanged model.

Sources: Pause-token paper · Planning-token paper, §2

Paper details: Think before you speak: Training language models with pause tokens · Guiding Language Model Reasoning with Planning Tokens

18 papers, oldest first

Dates usually refer to the first arXiv submission. Search or filter these papers →

AITP 2023

Thinking Tokens for Language Modeling

David Herel, Tomas Mikolov

Gives a recurrent language model extra hidden-state updates by inserting special tokens after each word. Tests whether these updates improve next-word prediction.

About this date

Date source: AITP presentation date; the earlier public release date of the conference abstract is unverified. Linked arXiv version: May 14, 2024.

Thinking tokens
Paper ↗ Details & citations arXiv:2405.08644
arXiv

Efficient Pretraining Length Scaling

Bohong Wu, Shen Yan, Sijun Zhang, Jianqiao Lu, Yutao Zeng, Ya Wang, Xun Zhou

Adds hidden decoding tokens during pretraining, then discards their key/value cache entries after use. Keeps the original tokens' entries to preserve longer-range context.

Thinking tokensRecurrent reasoning
Paper ↗ Details & citations arXiv:2504.14992
arXiv

Chain Of Thought Compression: A Theoretical Analysis

Juncai Li, Ru Li, Yuxiang Zhou, Boxiang Ma, Jeff Z. Pan

Analyzes how skipping intermediate steps weakens learning signals in a simplified parity-task model. Introduces NatBool-DAG to test logical dependencies and ALiCoT, which supervises learned token states with intermediate logical labels or explicit-CoT representations.

Analysis and evaluationInternalized reasoningThinking tokens
Paper ↗ Details & citations arXiv:2601.21576
arXiv

Almost Free State Prediction Separation

John Langford, Nathan Godey, Giovanni Monea, Yoav Artzi, Harry Dong, Ying Fan, Gustavo de Rosa, Zheng Zhan

Moves pause-token computation into a parallel, weight-shared prediction stream, providing additional internal compute without increasing generated sequence length or key/value-cache length.

Thinking tokensAlternative generation methods
Paper ↗ Details & citations arXiv:2609.03807
arXiv

Trading Depth for Time in Recurrent Transformers

Zeyi Huang, Xuehai He, Yelong Shen, Yong Jae Lee

Inserts a hidden-state refinement step between consecutive text tokens in a recurrent transformer. Compares this extra thinking time with adding physical layers or transformer loops under matched computation budgets.

Recurrent reasoningThinking tokens
Paper ↗ Details & citations arXiv:2609.21605
arXiv

Skip the Talk, Re-Focus on Vision: Latent Reasoning for Reasoning Segmentation in Multimodal Large Language Models

Tianhang Guo, Yulin He, Wei Chen, Wenjuan Zhou, Yuhang Li, Xinbiao Gan

LIRSeg generates a fixed sequence of learned special tokens before a target description and bounding box used for segmentation. Spatial alignment grounds the tokens' hidden states in relevant image regions, followed by training with segmentation rewards.

Thinking tokens
Paper ↗ Details & citations arXiv:2609.30783
arXiv

Ceiling of a Task: When Can a Transformer Succeed Without Its Chain of Thought?

Jiashu He, Jinxuan Fan, Xiao Xiao, Radu Marculescu, Alejandro Ribeiro

Analyzes tasks for which a fixed-depth transformer needs an informative chain of thought to exceed a task-specific accuracy limit. Combines circuit-based results with experiments that replace, erase, or shuffle reasoning tokens, including comparisons with filler tokens.

Analysis and evaluationThinking tokens
Paper ↗ Details & citations arXiv:2609.33134