Predicting human decisions under risk and uncertainty remains a fundamental challenge across disciplines. Existing models often struggle even in highly stylized tasks like choice between lotteries. We introduce BEAST Gradient Boosting (BEAST-GB), a hybrid model integrating behavioral theory (BEAST) with machine learning. We first present CPC18, a competition for predicting risky choice, in which BEAST-GB won. Then, using two large datasets, we demonstrate BEAST-GB predicts more accurately than neural networks trained on extensive data and dozens of existing behavioral models. BEAST-GB also generalizes robustly across unseen experimental contexts, surpassing direct empirical generalization, and helps refine and improve the behavioral theory itself. Our analyses highlight the potential of anchoring predictions on behavioral theory even in data-rich settings and even when the theory alone falters. Our results underscore how integrating machine learning with theoretical frameworks, especially those-like BEAST-designed for prediction, can improve our ability to predict and understand human behavior.
View on arXiv@article{plonsky2025_1904.06866,
title={ Predicting human decisions with behavioral theories and machine learning },
author={ Ori Plonsky and Reut Apel and Eyal Ert and Moshe Tennenholtz and David Bourgin and Joshua C. Peterson and Daniel Reichman and Thomas L. Griffiths and Stuart J. Russell and Evan C. Carter and James F. Cavanagh and Ido Erev },
journal={arXiv preprint arXiv:1904.06866},
year={ 2025 }
}