Test-time Computing: from System-1 Thinking to System-2 Thinking
Authors: name: Yixin Ji, name: Juntao Li, name: Hai Ye, name: Kaixin Wu, name: Jia Xu, name: Linjian Mo, name: Min Zhang

The remarkable performance of the o1 model in complex reasoning demonstrates
that test-time computing scaling can further unlock the model's potential,
enabling powerful System-2 thinking. However, there is still a lack of
comprehensive surveys for test-time computing scaling. We trace the concept of
test-time computing back to System-1 models. In System-1 models, test-time
computing addresses distribution shifts and improves robustness and
generalization through parameter updating, input modification, representation
editing, and output calibration. In System-2 models, it enhances the model's
reasoning ability to solve complex problems through repeated sampling,
self-correction, and tree search. We organize this survey according to the
trend of System-1 to System-2 thinking, highlighting the key role of test-time
computing in the transition from System-1 models to weak System-2 models, and
then to strong System-2 models. We also point out a few possible future
directions.