Fire and Human Speech May Be Fundamentally Linked, New Hypothesis Proposes

Fire and human speech may be fundamentally linked, according to a new hypothesis proposed by University of St Andrews primatologist Catherine Hobaiter and Dartmouth College anthropologist Nathaniel Jay Dominy in a paper published in the journal Royal Society B: Biological Sciences.

The researchers argue that the conditions surrounding an evening fire may have shaped the evolution of spoken language, helping explain why humans are so much better than our closest relatives, chimpanzees and gorillas, at communicating with sound. The proposal is purely hypothetical, the authors say, but is built from testable claims drawn from several fields.

Chimpanzees and gorillas communicate effectively through gestures such as hooting, teeth-baring, chest-beating and branch-shaking, without complex speech. Hobaiter and Dominy write that behaviours often assumed to require language — including tool use, transferring knowledge and social coordination — can be ruled out as the key force behind language's evolution, since none of them is unique to humans or strictly requires speech.

Managing a localised fire for food, safety and comfort is, like speech, a uniquely human behaviour that appears to have developed around the same time as complex spoken language. The researchers propose that time spent around a fire may have given early humans both the opportunity and the incentive to reflect collectively and tell stories.

The paper lays out around half a dozen testable claims, including whether firelight's flicker affects how people interpret gestures, and whether the longer wavelengths of light from embers could extend hours of evening socialising without disrupting sleep. The authors say evidence is still needed to build a case for or against the role of firelight in the evolution of rich, spoken language.