Platt started working with two superstar primatologists, Dorothy Cheney and Robert Seyfarth, who were based at Penn but studied free-ranging monkeys in Africa. The scientists were best known for experiments in which they’d record monkey vocalizations during social interactions and then, later, play them over a concealed loudspeaker and observe how the animals reacted.

That work didn’t quite satisfy Platt, either. He wanted to know how, exactly, the monkey brain encodes social behaviors — and whether our brains do it in the same way.



So he left anthropology and turned to neuroscience. For the past decade or so, he has been recording from individual cells in the brains of rhesus macaque monkeys while the animals do simple tasks — like