Two million years ago, hominins heard the world very differently from modern humans, according to a new study.

Researchers at Binghamton University analyzed the fossilized ear bones of two early hominins from South Africa, A. africanus and P. robustus, which lived 3.3 million and 1.8 million years ago. With computerized tomography scans, they were able to virtually reconstruct the ears and estimate the hominins’ auditory abilities.

“They didn’t hear as well as humans, and they are more like chimps,” said Rolf Quam, an anthropologist at Binghamton University and one of the study’s authors.

There was one exception. From one to three kilohertz, the hominins had better hearing than modern humans and chimpanzees.