Feels like a lot of commenters here miss the difference between just doing chain-of-thought prompting, and what is happening here, which is learning a good chain of thought strategy using reinforcement learning. "Through reinforcement learning, o1 learns to hone its chain of thought and refine the strategies it uses." When looking at the chain of thought (COT) in the examples, you can see that the model employs diffe…
It’s basically a scaled Tree of Thoughts
Based on the quick searching it seems like they are using RL to provide positive/negative feedback on which "paths" to choose when performing CoT.