Readers ponder sign language in ancient humans, looped universe

A sign of our past?

Deaf experimental psychologist Rain Bosworth has found that babies have an intrinsic ability to recognize sign language, Meghan Rosen reported in “Primed to sign” (SN: 4/26/24).

Reader Suzanne Lijek wondered if our innate sensitivity to sign language could stem from its use by ancient humans.

Our ancestors probably communicated through both gestures and speech, says cognitive neuroscientist Karen Emmorey of San Diego State University. This could be why all speakers (signers included) gesture, no matter the language, she says. But exactly how language emerged is still a question. Some scientists think spoken language evolved from vocal communications like grunts and alarm calls. Others argue that our ancestors learned first to communicate through gestures, laying scaffolding in the brain for spoken language to evolve. But why speech became dominant is unclear. “If gestures were first, then we might all be signers, since sign languages have all the expressive capabilities of spoken languages,” Emmorey says. Instead, gesture and speech probably evolved together, she suggests.

Full circle

The shape of our universe might be complex, like a doughnut, Emily Conover reported in “The universe may loop back on itself” (SN: 5/13/24).

Reader Jim Schmitz asked if this loopiness could let scientists spot distant objects in outer space by simply looking in the opposite direction.

That is one of the original ideas for how to search for cosmic topology, says theoretical physicist Glenn Starkman of Case Western Reserve University in Cleveland. “If you can see the same object in two directions on the sky and recognize it, that would be proof that you can see around the universe.” Scientists have tried, but it’s challenging. The object might appear at different points in its history and from different perspectives, Starkman says. He likens it to “seeing a picture of your friend from the back when they were a baby and hoping to recognize them.” As searches came up empty, scientists concluded that the universe is too big to see a distant object from two directions.

Correction

“What’s the human speed limit?” incorrectly stated that Usain Bolt’s top speed during his 2009 record-setting run was nearly 40 kilometers per hour (SN: 7/24/24). That was actually Bolt’s average running speed. His top speed was 44.72 km/h.