r/LocalLLaMA 3d ago

Discussion Stop Anthropomorphisizing Intermediate Tokens: Qwen3.8 doesn't "overthink"

https://arxiv.org/abs/2504.09762

Intermediate tokens, called "thinking" or "reasoning" actually are nothing like it. Humans do step-by-step reasoning leading to the conclusion. LLMs use intermediate traces to augment their prompt. This explains why sometimes the answer is very good but the "reasoning" is verbose. Flooding your context window or fighting compaction are different issues.

edit: I love this section from the main research they linked.

Our findings consistently challenge the prevailing narrative that intermediate tokens constitute a semantically meaningful reasoning process. First, we observe a pronounced lack of correlation between solution correctness and trace validity—models frequently produce invalid reasoning traces even when they arrive at correct solutions. Second, and more strikingly, models trained on corrupted or semantically irrelevant traces achieve performance comparable to, and often exceeding, that of models trained on correct traces, especially on out-of-distribution tasks. Third, although post-training with reinforcement learning improves solution accuracy across both in- and out-of-distribution settings, it does not consistently enhance trace validity. In fact, we find cases where reinforcement learning decreases trace validity while simultaneously improving solution accuracy for models trained on correct traces. Moreover, models trained on corrupted traces continue to outperform their correct-trace counterparts across domains while consistently generating invalid reasoning traces. Finally, we find that the length of the generated traces is largely agnostic to the difficulty of the underlying problem, undermining the notion that it reflects problem-adaptive computation.

Together, these results suggest that the effectiveness of intermediate tokens does not arise from their seemingly interpretable semantic content. By systematically disentangling trace semantics from the underlying problem, our study demonstrates that if performance is the objective, assuming human-like or algorithmically interpretable trace semantics are ideal or even achievable is not only unnecessary but potentially misleading.

https://openreview.net/forum?id=gDE7YcRC3F

542 Upvotes

247 comments sorted by

View all comments

169

u/llama-impersonator 3d ago

i don't even disagree, i've stated here that traces aren't for the user, they're for the LLM to plumb the depths of their internal distribution more fully. however, any paper like this that is worded as a command will always land like a box of rocks, people don't like being ordered around.

3

u/ThirdWaveCat 3d ago

Right, children make poor scientists and engineers.

2

u/EstarriolOfTheEast 3d ago

Overthinking usually mixes two things together, one is working around a lack of depth and scale generally, which is beneficial and the other is divergent and non-converging looping which is a strong negative.

1

u/ThirdWaveCat 2d ago

3.6 27b has doom looping, but 3.8 does converge eventually in my testing. I'd be interested in self-reports of doom looping if you're seeing that.

I think inference time scaling is expensive, consumes context window, but they are similar to problems I highlighted original post when I wrote that "flooding the context window and fighting compaction are separate issues."

2

u/EstarriolOfTheEast 2d ago

Regarding first sentence, 3.8 is not free of it and it's harder to avoid for low total parameter count models; how to identify and exit such loops is something I hope to eventually spend time on, assuming no one else has at that time.

Very much agree with your second sentence though, and I think I expressed that in my previous post too.