Supplementary material from "Can Large Language Models help predict results from a complex behavioural science study?"

We tested whether Large Language Models (LLMs) can help predict results from a complex behavioural science experiment. In Study 1, we investigated the performance of the widely used LLMs GPT-3.5 and GPT-4 at forecasting the empirical findings of a large-scale experimental study of emotions, gender, and social perceptions. We found that GPT-4, but not GPT-3.5, matched the performance of a cohort of 119 human experts, with correlations of 0.89 (GPT-4), 0.07 (GPT-3.5), and 0.87 (human experts) between aggregated forecasts and realized effect sizes. In Study 2, providing participants from a university subject pool the opportunity to query a GPT-4 powered chatbot significantly increased the accuracy of their forecasts. Results indicate promise for AIs to help anticipate—at scale and minimal cost—which claims about human behaviour will find empirical support and which ones will not. Our discussion focuses on avenues for human-AI collaboration in science.