New multi-source research shows that olive baboons and rhesus macaques can match geometric shapes on touchscreens in ways that align with how young children and some adults process geometry, challenging the idea that geometric intuition is uniquely human. Led by Jessica Cantlon, the studies used two-dimensional shape matching and demonstrated that monkeys, children, and adults rely on similar perceptual representations when judging geometric similarity, with only some abstract or symbolic processing adding nuance. The experiments, which credit open data and cross-cultural participants including Indigenous groups such as the Tsimane', suggest geometry is not a human-exclusive faculty but part of a shared primate mind. Education and formal training appear to strengthen geometric reasoning but do not fully account for primitive competences, as shown by comparisons across diverse populations. The research, published in the Proceedings of the National Academy of Sciences, frames geometric intuition on a continuum rather than as a categorical human-versus-primates distinction. Taken together, these findings imply that basic geometric understanding is a common feature of primate cognition, refined by experience and culture.