A Reinforcement Learning and Sequential Sampling Model Constrained by Gaze Data

Reinforcement learning models can be combined with sequential sampling models to fit choice-RT data. The combined models, known as RL-SSMs, explain a wide range of choice-RT patterns in repeated decision tasks. The present study shows how constraining an RL-SSM with eye gaze data can further enhance its predictive ability. Our model assumes that learned option values and relative gaze independently influence the accumulation of evidence prior to choice. We evaluated the model on data from two eye-tracking experiments (total N = 133) and find that it makes better out-of-sample predictions than other models with different ways of integrating values and gaze at the decision stage. Further, we show that it captures a variety of empirical effects, including the finding that choices become more accurate as the higher-value option receives a greater proportion of the total fixation time. The model can be used to understand how learned option values interact with visual attention to influence choice, joining together two major—but mostly separate—research traditions in the cognitive science of decision making.