A language model learned uncertainty and reached results with 41 percent fewer experiments

A Nature Machine Intelligence study introduces GOLLuM, a framework that trains language models through the probabilistic objective used in Gaussian-process Bayesian optimization. Instead of treating a language model as a confident generator of experimental suggestions, the method reshapes its internal representation using observed outcomes and calibrated uncertainty so it can help decide which experiment to run next. Starting from ten low-performing experiments, GOLLuM ranked first on average across 23 tasks spanning organic synthesis, process chemistry, materials, catalysis, and molecular design. It matched traditional Bayesian optimization's final performance with a median 41 percent fewer iterations. In a Buchwald–Hartwig reaction benchmark, the approach nearly doubled the discovery rate for high-performing conditions compared with expert quantum-chemical descriptors and state-of-the-art language models, 43 percent versus 24 to 25 percent. The result matters because laboratory time, materials, and failed experiments are expensive. It also shows that uncertainty can be part of a model's training objective rather than a confidence label added afterward. The evidence comes from benchmarked experimental-design tasks, not unrestricted autonomous laboratories. Domain review, physical safety limits, dataset quality, secondary objectives, replication, and transparent decision records remain necessary before an optimization gain becomes a discovery system people can trust.