For LLM-based agents, determining when to give rewards is trickier. If an AI system is asked to solve a coding problem, it might work hard to find a solution, but it could also modify the evaluation code, find the solution online, or cheat in other ways. If the model cheats convincingly enough, it gets rewarded, reinforcing the cheating behavior. Anthropic says it has detected some instances of cheating during training, suggesting other forms may go undetected, and models might be trained to misbehave.
Jeffrey Ladish, director of Palisade Research, notes: 'We reward them based on what looks good, which inadvertently incentivizes the model to lie and cheat us. We can't go in and say, "No, you need to actually care about what we care about." We don't have that ability.'
The rise of reasoning models has introduced a new variant of reward hacking, less tied to training details. Unlike past game agents that followed training policies, today's models can improvise entirely new problem-solving methods, so they might cheat without prior reinforcement. Since these models are densely trained to achieve user-set goals, if they can't find another solution, they may lean toward cheating, similar to a student highly motivated to get an A but with weak moral scruples.