Learning to Play Text-based Adventure Games with Maximum Entropy Reinforcement Learning
This work addresses the problem of training instability and sparse rewards in RL for text-based games, offering an incremental improvement for researchers in language-based AI.
The authors tackled the challenge of applying reinforcement learning to text-based adventure games by adapting the soft-actor-critic algorithm with reward shaping, achieving higher scores than Q-learning methods in half the training steps.
Text-based games are a popular testbed for language-based reinforcement learning (RL). In previous work, deep Q-learning is commonly used as the learning agent. Q-learning algorithms are challenging to apply to complex real-world domains due to, for example, their instability in training. Therefore, in this paper, we adapt the soft-actor-critic (SAC) algorithm to the text-based environment. To deal with sparse extrinsic rewards from the environment, we combine it with a potential-based reward shaping technique to provide more informative (dense) reward signals to the RL agent. We apply our method to play difficult text-based games. The SAC method achieves higher scores than the Q-learning methods on many games with only half the number of training steps. This shows that it is well-suited for text-based games. Moreover, we show that the reward shaping technique helps the agent to learn the policy faster and achieve higher scores. In particular, we consider a dynamically learned value function as a potential function for shaping the learner's original sparse reward signals.