Advancements in Natural Language Processing (NLP), have led to the emergence
of Large Language Models (LLMs) such as GPT, Llama, Claude, and Gemini, which
excel across a range of tasks but require extensive fine-tuning to align their
outputs with human expectations. A widely used method for achieving this
alignment is Reinforcement Learning from Human Feedback (RLHF), which, despite
its success, faces challenges in accurately modelling human preferences. In
this paper, we introduce GazeReward, a novel framework that integrates implicit
feedback -- and specifically eye-tracking (ET) data -- into the Reward Model
(RM). In addition, we explore how ET-based features can provide insights into
user preferences. Through ablation studies we test our framework with different
integration methods, LLMs, and ET generator models, demonstrating that our
approach significantly improves the accuracy of the RM on established human
preference datasets. This work advances the ongoing discussion on optimizing AI
alignment with human values, exploring the potential of cognitive data for
shaping future NLP research.