Could Cavemen hear better than we can?

Science Magazine published an article suggesting early hominins, who lived over two million years ago, could actually hear better than us. The study showed that their hearing exceeded ours at certain frequencies.

Scientists are convinced that early humans were able to hear mid-frequency sounds better than modern humans. Sharp mid frequency hearing acuity would allow early humans to communicate better in the wild while hunting.

So, how on earth can scientists study the hearing of someone who lived more than two million years ago?

Actually, anatomical properties of the auditory system has been found preserved in fossilized skeletal structures. This has allowed researchers to estimate auditory capability with amazing accuracy. After studying a fossilized skull and middle ear bones, scientists reconstructed 3D computer models that allowed them to predict hearing abilities.

Hearing & communication needs have changed over time

By studying fossils, scientists found anatomical differences in the outer and middle ear structures. External auditory ear canals were quite shorter and wider than ours, and were also described as “more trumpet” in shape. The eardrum (tympanic membrane) was smaller; the bones in the middle ear were a different size than today’s ears.

Differences in the three bones in the middle ear (ossicular chain), which are roughly the size of a grain of rice, were also noted, confirming a difference in hearing between then and now. The spiral snail shaped bone structure in the inner ear (cochlea), was shorter in early humans. The shorter cochlea would emphasize mid-frequency sounds, researchers believe.

Structural differences in our ancestor’s ears suggest they had a more increased midrange hearing capability, between 1000 and 3000 Hz. According to researchers, ancient humans could hear the mid-frequency range better than modern humans.

Although early hominins didn’t communicate like we do today, communication was still very important. Researchers have found that early vocalizations mainly consisted of vowel sounds with an “increased emphasis on short-range vocal communication in open habitats.”

As communication evolved, so did our hearing system

Over many years, evolutionary changes shifted the mid-frequency focus higher. Today’s humans have an extended bandwidth of audibility that favors and includes higher frequencies. Modern humans can hear better over a wider frequency range (1-6k Hz).

Our ability to hear on an expanded frequency range (1-6k Hz) is needed to hear most sounds used in spoken language. For example, the English language uses high frequency consonant sounds like S, H, and F.  Children’s and female voices tend to have a higher pitch than male voices - high frequency hearing is important for understanding these voices.

By comparing anatomical hearing in early humans to modern humans, researchers hope to gain a better understanding of the evolution of speech, communication and language. 

By Starkey Canada

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