The model they use in that paper is a toy model of an LLM that’s so different from an actual LLM that I doubt the results mean anything at all.
Specifically, they train a model from scratch. The model architecture is apparently based on Llama but the size is 34M parameters. Not 34B, 34M. This is a fraction of the size of GPT-2.
Luckily, they don’t use the model as a language model. It neither receives text, generates text, nor uses text to think. Instead the inputs are strings like “A01 B10 C73 D27”, and the only possible outputs are “True” and “False”. They are expecting the model to solve a specific math problem encoded by those numbers, and do nothing else. The chain of thought is also numbers, in the scenario that’s supposed to represent a real chain of thought (as opposed to the filler-token scenario and the no-CoT scenario). The numbers in question are manually trained into the model based on one possible algorithmic decomposition of the problem; the model does not learn to generate its own CoT.
Even with all those limitations, for their main problem (3SUM), they only show that filler tokens are better than no CoT at all. They don’t show how that compares to ‘real’ CoT, at least as far as I can see (admittedly I only skimmed). They do make this comparison for their easier problem (2SUM), but on that problem both filler token CoT and ‘real’ CoT are mostly saturated, so the results don’t mean much.
>The model they use in that paper is a toy model of an LLM that’s so different from an actual LLM that I doubt the results mean anything at all.
Sorry, but it sounds like you aren't cut out for transformer based LLM research if you can't interpret the results.
Each layer in a transformer has its own KV cache that feeds from the previous layers output. Those internal layer activations are not subject to training loss directly. The model can spit out a dot but still perform additional computations within those layers.
The dot effectively prevents information from flowing from the final layer into the output, but all the intermediate layer activations are still available for future tokens. The limitation here is that information cannot be passed from the last layer to the first layer.
If a long running calculation needs to go through all layers and then be refined further, CoT becomes mandatory because CoT tokens are the only way to pass information up to the first layer, but since they are not as information dense as the internal activations, replacing them with a dot does not degrade performance as much as one would expect.
The model they use in that paper is a toy model of an LLM that’s so different from an actual LLM that I doubt the results mean anything at all.
Specifically, they train a model from scratch. The model architecture is apparently based on Llama but the size is 34M parameters. Not 34B, 34M. This is a fraction of the size of GPT-2.
Luckily, they don’t use the model as a language model. It neither receives text, generates text, nor uses text to think. Instead the inputs are strings like “A01 B10 C73 D27”, and the only possible outputs are “True” and “False”. They are expecting the model to solve a specific math problem encoded by those numbers, and do nothing else. The chain of thought is also numbers, in the scenario that’s supposed to represent a real chain of thought (as opposed to the filler-token scenario and the no-CoT scenario). The numbers in question are manually trained into the model based on one possible algorithmic decomposition of the problem; the model does not learn to generate its own CoT.
Even with all those limitations, for their main problem (3SUM), they only show that filler tokens are better than no CoT at all. They don’t show how that compares to ‘real’ CoT, at least as far as I can see (admittedly I only skimmed). They do make this comparison for their easier problem (2SUM), but on that problem both filler token CoT and ‘real’ CoT are mostly saturated, so the results don’t mean much.
>The model they use in that paper is a toy model of an LLM that’s so different from an actual LLM that I doubt the results mean anything at all.
Sorry, but it sounds like you aren't cut out for transformer based LLM research if you can't interpret the results.
Each layer in a transformer has its own KV cache that feeds from the previous layers output. Those internal layer activations are not subject to training loss directly. The model can spit out a dot but still perform additional computations within those layers.
The dot effectively prevents information from flowing from the final layer into the output, but all the intermediate layer activations are still available for future tokens. The limitation here is that information cannot be passed from the last layer to the first layer.
If a long running calculation needs to go through all layers and then be refined further, CoT becomes mandatory because CoT tokens are the only way to pass information up to the first layer, but since they are not as information dense as the internal activations, replacing them with a dot does not degrade performance as much as one would expect.
Also 2504.09762: Stop Anthropomorphizing Intermediate Tokens as Reasoning/Thinking Traces!
https://arxiv.org/abs/2504.09762