Repeating Past Actions Biases Future Choices More Than Logic

A Dresden University of Technology study analyzing over 700 participants across nine new tasks and six existing datasets finds that repeating past actions biases current decisions more strongly than explicit value reasoning. A hierarchical Bayesian reinforcement-learning model incorporating reward learning and action repetition outperformed alternatives, suggesting that some so-called irrational preferences arise from habit-like carryover rather than complex calculations, with implications for everyday habits and how environments shape choices.