I find that even with the longer prefill of “I will now answer immediately with the answer. The answer is” the model often reasons. I was hoping that the model would be reluctant to break this text prediction task and reason, but apparently not.
I think “how easy does the task seem” and “how much does the task seem like one on which reasoning seem like it should help” might have a big effect on whether the model respects the prefil vs reasons, so your sentence completion task might be not be representative of how the model always behaves.
I find that even with the longer prefill of “I will now answer immediately with the answer. The answer is” the model often reasons. I was hoping that the model would be reluctant to break this text prediction task and reason, but apparently not.
I think “how easy does the task seem” and “how much does the task seem like one on which reasoning seem like it should help” might have a big effect on whether the model respects the prefil vs reasons, so your sentence completion task might be not be representative of how the model always behaves.