OpenAI's latest update to ChatGPT includes a new 'Think' feature, which has caused some confusion among users. The feature, available in models such as GPT-4o, GPT-4o-mini, o1-mini, and o1, but not for Custom GPTs, automatically switches to the o1 model in the background when activated. This toggle, also referred to as 'Use more intelligence', has led to speculation about its functionality, with some users questioning whether it enhances the model's reasoning capabilities or if it simply calls another model for processing. There is also speculation about whether reasoning reinforcement learning (RL) is involved in this feature.