One ancient habit could have changed human speech

A controlled fire could have provided people not only with warmth and shelter, but also with a few extra hours for socialising. Researchers suggest that evening storytelling by the fire created conditions in which spoken language gradually became more important than gestures.

This is not a proven account of the origin of language, but a theoretical model. The authors combined data from anthropology, primatology and research into light, and then formulated testable hypotheses.

Details

The hypothesis was proposed by primatologist Catherine Hobaiter of the University of St Andrews and anthropologist Nathaniel Dominy of Dartmouth College. Their article has been published in the peer-reviewed journal *Proceedings of the Royal Society B*.

The authors’ starting point is the sophisticated gesticulation of great apes. According to their theory, early humans may also have solved many everyday tasks through a combination of gestures and simple sounds. However, once darkness fell, gestures became less reliable, particularly in dim light, whereas the voice allowed communication without constant eye contact.

Fire also extended the active part of the day. According to data on modern hunter-gatherer communities cited in the article, it can add around four hours to waking hours. The authors also refer to earlier observations of the Zhuang people: during the day, conversations tended to focus on practical matters, whilst by the fire people were more likely to tell stories. These observations do not prove that language arose in this precise way, but they do show how the evening setting can alter the content of communication.

The researchers draw attention to the spectrum and rhythm of the flame. There is relatively little blue light in the fire, and its brightness fluctuates constantly. Preliminary measurements indicated a flicker frequency of approximately 2.5–2.7 hertz — which is close to the slow rhythms of speech. The possible synchronisation of the speaker’s and listeners’ attention remains a hypothesis for now: it was not tested on human subjects in this study.

The authors have proposed six testable predictions. These include a distinctive speech rate during storytelling, a more complex narrative structure, reduced clarity of gestures during flickering, and more pronounced physiological synchronisation between the storyteller and the listeners. It is precisely such experiments that should demonstrate whether the proposed mechanism works.

Why this is important

The origins of language leave almost no direct archaeological traces: it is impossible to find the first spoken word or to date the first story with any precision. This new study transforms the familiar image of people gathered round a campfire from a charming story into a set of specific questions that can be tested through the characteristics of speech, perception and behaviour.

That said, the article does not establish when spoken language first emerged, nor does it prove that fire gave rise to it. It does not involve any new field experiments with people, and some of the arguments are based on preliminary measurements and the comparison of data from different fields. The authors themselves warn against the risk of romanticising the role of the campfire.

The value of the hypothesis lies elsewhere: it proposes a possible environment in which the voice gained an advantage over gestures, and conversation could extend beyond immediate everyday tasks. If these predictions are confirmed, evening storytelling could be regarded as one of the factors in the evolution of human speech — but not as its sole cause.

Source

• Firelight may have sparked human storytelling by extending social hours, Phys.org / University of St Andrews, 1 September 2026.
• Catherine Hobaiter, Nathaniel J. Dominy. Firelight and the origins of spoken language, Proceedings of the Royal Society B, 2 September 2026. DOI: 10.1098/rspb.2026.0602.
• Photo page on Wikimedia Commons: Phil Coffman, CC0 1.0.