Monkeys use some of the same basic mental strategies as people do to perceive abstract relationships between shapes, a new study suggests. "So there's a thread of continuity that runs through geometric reasoning between humans and nonhumans." "This study provides compelling evidence that, at least for geometric reasoning, the difference between humans and other primates is more quantitative than qualitative." In other words, the study suggested that baboons and macaques don't lack the ability to reason about geometry. A geometric matching gameThe researchers tested eight adult monkeys: four rhesus macaques (Macaca mulatta) and four olive baboons (Papio anubis).