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Chain of thought prompting ("think step by step") only encourages the model to break the problem into steps, which allows it to incrementally build upon each st
by HarHarVeryFunny 2y ago
Chain of thought prompting ("think step by step") only encourages the model to break the problem into steps, which allows it to incrementally build upon each step (since the output is fed back in as part of the input).
Reasoning requires more than chain of thought, since it's often not apparent what the next step should be - you (human, or model) may go down one path of reasoning only to realize it's going nowhere, and have to back up and try something else instead. This ability to "back up" - to realize that an earlier reasoning "step" was wrong and needs to be rethought is what was mostly missing from models that (unlike o1, etc) hadn't been trained for reasoning.
The reason non-reasoning models can't reason appears to be because this type of chain-of-consciousness thought (thinking out loud, mistakes and all) when trying to figure out a problem is hugely underrepresented in a normal training set. Most writing you find on the internet, or other sources, is the end result of reasoning - someone figured something out and wrote about it - not the actual reasoning process (mistakes and all) that got them there.
It's still not clear what OpenAI had to do, if anything, to help bootstrap o1 (special hand-created training data?), but basically by using RL to encourage certain types of reasoning pattern, they were able to get the model to back-up and self-correct when needed. DeepSeek-R may well have used o1 reasoning outputs as a bootstrap, but have been able to replicate RL training to encourage self-correcting reasoning in the same way.
One interesting aspect of DeepSeek-R is that they have shown that once you have a reasoning model, you can run it and use it to generate a bunch of reasoning outputs that can then be used as normal training data to fine-tune a non-reasoning model, even a very small one. This proves that, at least to some degree, the reason non-reasoning models couldn't reason is just because they had not been trained on sufficient self-correcting reasoning examples.
- naasking 2y ago> since it's often not apparent what the next step should be Backtracking assumes depth-first search, which isn't strictly needed as you could explore all possible options in parallel in a breadth-first manner, but incrementally until one branch returns a satisfactory answer. > This proves that, at least to some degree, the reason non-reasoning models couldn't reason is just because they had not been trained on sufficient self-correcting reasoning examples. For sure this is a big reason, and probably also part of the reason they hallucinate rather than say they don't know or aren't sure.
- HarHarVeryFunny 2y ago> Backtracking assumes depth-first search, which isn't strictly needed as you could explore all possible options in parallel in a breadth-first manner You could in theory, but it'd be massively/prohibitively more expensive - exploring a whole tree just to end up using a single branch. It'd be like trying to have a computer play chess by evaluating EVERY branching position out to some fixed depth, rather than using MCTS to prune away unpromising lines. Not only that, but reasoning in general (of which LLM-based reasoning is only a limited case) isn't just about search - it can also require exploration and acquisition of new knowledge if you run into an impasse that your past experience can't handle. If AI systems hope to achieve human-level AGI, they will need to change to support continuous learning and exploration as a part of reasoning, which naturally means more of a depth-first approach (continue until you hit an impasse) with backtracking. You can say that hallucination is due to gaps in the training set, but of course humans don't have that problem because we know what we know, and have episodic memories of when/where/how we learned things. LLMs have none of that.
- Demlmlm 2y ago[dead]