You can blame fish for why you gesticulate when you talk.

“We have traced the evolutionary origins of the behavioral coupling between speech and hand movement back to a developmental compartment in the brain of fishes,” said Cornell University Professor Andrew Bass….wait a minute….his last name….the subject….something fishy is going on here.

Nevertheless, carry on, fish expert.

“Pectoral appendages (fins and forelimbs) are mainly used for locomotion,” he said. “However, pectoral appendages also function in social communication for the purposes of making sounds that we simply refer to as non-vocal sonic signals, and for gestural signalling.”

In fish, a single compartment in the hindbrain controls the pectoral muscles as well as the muscles used to produce sound. You can find the same close coupling of neural networks in mammals.

“Coupling of vocal and pectoral-gestural circuitry starts to get at the evolutionary origins of the coupling between vocalization (speech) and gestural signalling (hand movements),” Bass said. “This is all part of the perhaps even larger story of language evolution.”

Great, now every time I see someone gesticulate I’m going imagine that person as a fish. Thank you, science.

(Image via Flickr: Caroline / Creative Commons.)