A University of St. Andrews-led research team has proposed that the red wavelengths of flickering light emitted by early human ancestors’ campfires helped reprogram the human brain to boost social and verbal communication, leading to modern language and storytelling behaviors found only in humans.
The team, which included researchers from Dartmouth College, said the study builds on earlier theories linking fire and language to the extra hours it added to the day.
However, their findings suggest that the biological changes caused by fire use may have enabled complex language as much as fire-associated behavioral changes, accelerating the evolution of verbal communication away from the ape-like systems still used by modern apes toward more complex, “uniquely human” interactions.
Researchers Wondered if Firelight Reprogrammed the Human Brain
Catherine Hobaiter, a Professor of the School of Psychology and Neuroscience at the University of St Andrews and the lead author of a paper detailing the team’s idea, said she has always been fascinated by the origins of language.
“What was the first word?” the professor asked. “The first story?”
Unfortunately, Professor Hobaiter noted, many questions about the origin of humanity’s complex and diverse forms of verbal communication remain unanswered.
Some earlier research has explored a possible link between the first spoken words and the advent of controlled fire use. However, the team notes that most studies have focused primarily on the extra hours of practical light added to the end of each day.
Curious whether other biological mechanisms also contributed to the evolution of language and complex storytelling behavior, Professor Hobaiter and colleagues examined the effects of sitting around a campfire to see whether the emitted light could reprogram the human brain.
Potential Effects of Red Wavelengths and Flickering Lights
First, the team noted that one potential catalyst emitted by firelight that could help reprogram the human brain for complex language is the color of the light wavelengths emitted by campfires. Specifically, Hobaiter and colleagues noted that campfire light emits almost no blue wavelengths but instead mostly in the visible red spectrum.
Many modern studies have focused on the potentially adverse effects of exposure to blue light wavelengths from modern technology on sleep patterns and overall health. Conversely, the paper’s authors described the red wavelengths emitted from fire as ‘uniquely suited’ for human socializing, “allowing an extension to the day without negatively impacting sleep.”
Another component of firelight the study authors suggest could have reprogrammed the human brain for speech is the way a campfire behaves. Unlike a modern, steady light source, the authors noted that firelight “flickers.”
Hobaiter and colleagues said that neurons in the human brain synchronize firing patterns with external flickering lights. For example, flickering lights in movies and TV shows often come with warnings against possible neurological effects on vulnerable viewers. The research team said this mechanism might also help synchronize the behavior of those seated around the campfire, resulting in a much deeper feeling of connection.
Finally, the researchers noted that firelight emits infrared wavelengths, which may have also contributed to helping firelight reprogram the human brain for complex verbal communication.
Are We the Storytelling Ape?
When discussing the potential impact of their proposal, study co-author Nathaniel Dominy, the Charles Hansen Professor of Anthropology at Dartmouth College, said many of the chemical properties have been well researched. However, Professor Dominy also notes that understanding the properties of light that capture our attention and focus, thereby instilling “harmony and cooperation,” has received far less attention.
“Measuring these features is an exciting part of this project,” the study author added.
Professor Hobaiter agreed, while also noting the conundrum scientists face when explaining why humans speak, when “decades of research with other species has shown us that you don’t need language to learn from each other, to organize where and when to forage, to learn cultural knowledge about tools and songs, to co-ordinate hunting, or navigate social politics.”
“While other species share all these skills, there is a fundamental puzzle: we struggle to find evidence of key differences between human and ape communication,” Professor Hobaiter explained. “And yet, we are surrounded by evidence of human distinctiveness. For all their incredible, rich communication and cultures, no other ape is inventing algebra, writing King Lear, or heading out into interstellar space.”
“So, it’s especially exciting to be able to generate testable predictions, to be able to ask if, at the end of the day, we are the storytelling ape,” the professor added.
The paper “Firelight and the Origins of Spoken Language” was published in Proceedings of the Royal Society.
Christopher Plain has spent the last six years as Associate News Editor and Head Science Reporter at The Debrief. Follow and connect with him on X, learn about his novels at plainfiction.com, or email him at christopher@thedebrief.org.