Tomas trained at Uppsala and UC Berkeley, where his dissertation examined how children learn abstract words — words for time, number, and causation — from sparse and indirect evidence. That work has since broadened into a more general program on what children bring to the language-learning task: the conceptual primitives, attentional biases, and social cues that let them acquire, in a few years, a system that would take any adult decades to learn deliberately. He joined the Institute in 2020 and contributes to the Growing Minds Cohort.