In practice, the verifier is probably some kind of learned reward model (though it could be automated, like unit tests for code).
My guess is that a substantial amount of the verification (perhaps the majority?) was automated by training the model on domains where we have ground truth reward signals, like code, math, and standardized test questions. This would match the observed results in the o1 blog post showing that performance improved by a lot in domains that have ground truth or something close to ground truth, while performance was stagnant on things like creative writing which are more subjective. Nathan Lambert, the head of post-training at AI2, also found that doing continued RL training on ground truth rewards (which he calls RLVR) results in models that learn to say o1-like things like 'wait, let me check my work' in their chain of thought.
It's possible I'm using motivated reasoning, but on the listed ambiguous questions in section C.3, the answers the honest model gives tend to seem right to me. As in, if I were forced to answer yes or no to those questions, I would give the same answer as the honest model the majority of the time.
So if, as is stated in section 5.5, the lie detector not only detects whether the model had lied but whether it would lie in the future, and if the various model variants have a similar intuition to me, then the honest model is giving its best guess of the correct answer, and the lying model is giving its best guess of the wrong answer.
I'd be curious if this is more generally true - if humans tend to give similar responses to the honest model for ambiguous questions.
It's pretty common for people to use the terms "reward hacking" and "specification gaming" to refer to undesired behaviors that score highly as per an evaluation or a specification of an objective, regardless of whether that evaluation/specification occurs during RL training. I think this is especially common when there is some plausible argument that the evaluation is the type of evaluation that could appear during RL training, even if it doesn't actually appear there in practice. Some examples of this:
I think the literal definitions of the words in "specification gaming" align with this definition (although interestingly not the words in "reward hacking"). The specification can be operationalized as a reward function in RL training, as an evaluation function or even via a prompt.
I also think it's useful to have a term that describes this kind of behavior independent of whether or not it occurs in an RL setting. Maybe this should be reward hacking and specification gaming. Perhaps as Rauno Arike suggests it is best for this term to be specification gaming, and for reward hacking to exclusively refer to this behavior when it occurs during RL training. Or maybe due to the confusion it should be a whole new term entirely. (I'm not sure that the term "ruthless consequentialism" is the ideal term to describe this behavior either as it ascribes certain intentionality that doesn't necessarily exist.)