Science1 publisher3 min readPublished
To explain why most languages are spoken, a new paper turns to the campfire
Researchers at the University of St Andrews argue that firelight was bright enough to gather around and too dim to read a gesture by. Ancestral vocal tracts left no fossils, so the case rests on measurements of people alive now.
The Scientist · Science desk
What happened
- Researchers at the University of St Andrews argue that the dim light of a campfire helps explain why our ancestors moved from gestural communication to spoken language.
- Their premise is that fire gives light but not enough of it to carry the meaningful parts of early gesture, so a story told after dark needed a voice.
- The paper puts storytelling at the centre, pointing to complex structure and displacement in time and space: talk about things absent, past, or never real at all.
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Why it matters
- constraint No ancestral vocal tract or brain survived, so a hypothesis in this field cannot be confirmed against a specimen; it stands or falls on measurements taken from living people and living apes.
- decision Anyone wanting to test the central claim has to measure how much light a hand shape needs to be recognised at conversational distance, which is a question for a perception lab rather than an excavation.
- capability Making storytelling the trait under selection gives the idea a countable proxy, because the biases that decide which story elements survive retelling can be measured in existing oral corpora.
- precedent Social-bonding accounts of language origin now come with a specific physical setting attached, and later versions can be pressed to name a light level and a time of day.
The step that carries the argument is about light. Researchers at the University of St Andrews propose that the move from gesture to speech happened by the campfire, and the reason they give is legibility: firelight is, in the words of the Scientific American article describing the work, "potentially too dim for us to rely on it for the meaningful bits of early gestural language" [5]. If that holds, the rest follows without much strain. Hands become unreliable after dark, voices keep working, and gesture stays on as emphasis and emotion wrapped around speech [6]. The premise itself is a photometric question, namely how much light a hand shape needs in order to be read at conversational distance. The article does not report that measurement.
Two of the supporting points are about bodies alive today. Fire's colour spectrum suits human vision and, the authors argue, does not suppress the melatonin that helps us sleep the way modern screen light does [9]. Human neurons synchronize to the frequency of flickering firelight, which the authors say can improve shared social experience and bonding through rhythmic activity that promotes empathy [10]. Each point fits fire as a cause and fits fire as one instance of a more general effect equally well. The melatonin comparison settles something narrower, that an evening spent talking by a fire is compatible with sleeping afterwards. A visual system that entrains to flicker is consistent with firelight having shaped it, and equally consistent with any rhythmic stimulus producing the same entrainment.
The measured part of this story sits downstream of the origin question. Stories from early oral traditions resemble one another, and that resemblance is read as a transmission effect, with the most memorable elements surviving being retold [12]. The traits that survive are social and human-oriented content, counterintuitive elements, negative emotion and survival themes [13]. Researchers treat those biases as advantageous, on the grounds that swapping accounts of social bonds, unexpected dangers and survival pays off [14]. Somebody can go and count a corpus like that. It dates nothing and puts nobody beside a fire, but it is a claim about what retelling does to stories, and it could come out wrong.
Because the fossil record is missing, the setting matters for method. Vocal tracts and brains were soft tissue, and writing is recent, so the field works from how humans and other apes communicate now [1]. Every strand of evidence the article describes for the fireside account comes from the present: ape gesture systems [2], the iconicity of gesture and sign language [3], modern visual and circadian physiology [9][10], and oral-tradition corpora [12][16]. The article describes social bonding as an established explanation for the emergence of language, with the fireside context as what these authors add [11].
What to watch
- A photometric test of how well hand shapes are recognised at campfire illuminance would either support or undercut the paper's central premise.
- Whether neural entrainment to flicker is specific to firelight or occurs with any rhythmic light source at similar frequencies.
- Whether records of night-time communication in communities that still use firelight show the predicted drop in gestural content.