Scientists say pink noise can improve conversation

The Roman orator Cicero once proposed a set of rules for conversation: maintain an appropriate tone, avoid appearing bored, keep your temper, and refrain from rambling, especially about oneself. Now, researchers have built upon this foundation, identifying a specific signature that indicates an enjoyable exchange. According to scientists, the secret to a mutually satisfying conversation is a healthy dose of pink noise.

While the concept of noise colours is typically of more interest to physicists than linguists, a team at Dartmouth College in New Hampshire in the US discovered it offers new insights into what constitutes a quality chat. Kathryn O’Nell, the lead author of the study, explained: “In physics, people talk about pink noise as existing on the edge of chaos, where you can stay at a stable point, but you’re not stuck there for ever.” She added: “It’s particularly cool for conversation, because you can stay somewhere long enough to really get to know each other, to understand the topic, but you’re not stuck there while it gets stale.”

The research team examined over 1,000 conversations between strangers, who were asked to evaluate the interactions afterward. They discovered that participants enjoyed these exchanges more, expressed a desire to keep talking, and felt a stronger sense of connection when the interactions contained higher levels of pink noise. To determine if this trend persisted beyond strangers, the scientists performed a similar analysis on conversations between friends discussing their formative experiences, finding that increased pink noise correlated with greater enjoyment.

This phenomenon also had tangible real-world implications. When the team analysed speed-dating interactions, they observed that higher levels of pink noise were predictive of which pairs would choose to meet for a second date. These findings have been documented in the journal Science Advances. The authors acknowledged the difficulty of defining a great chat, noting in their paper: “Good conversation is like pornography – it is difficult to define, but we know it when we see it.”

Dr Emily Finn, a neuroscientist and senior author of the study, noted that while people often describe being 'in sync', the metaphor can be misleading. “In sync can be incredibly dull,” she said, explaining that people might mirror each other’s words and circle a single topic, resulting in boredom. To conduct the study, the researchers used an AI called MPNet to analyse the conversations. The software scored every turn of the chat across 768 criteria, including tone, meaning, and context, allowing the scientists to quantify how the dialogues progressed.

Conversations characterised by white noise occur when participants fail to follow the thread, leading to erratic jumps or dominance by one person. Conversely, red noise arises when individuals mirror each other’s language too closely, leading to a rut. Pink noise is described as a 'conversational Goldilocks zone' that balances flexibility and stability, where participants synchronise to explore a topic before drifting apart to introduce fresh ideas.

While the level of pinkiness depends on the participants, O’Nell suggested the skill might be learned. The team analysed podcasts hosted by pairs and found that the pinkiness of their exchanges increased over the first 50 episodes. Prof Elizabeth Stokoe, a conversation analyst at the London School of Economics, commended the team for challenging the idea that 'more similarity is better'. However, she argued that focusing solely on enjoyment might be limited.

“There’s a lovely study of a phone call in which a father and his daughter, a young woman with learning disabilities living in residential care, take a long time to say goodbye, and the ending is painful and poignant,” she said. “Reducing conversations to whether they are ‘enjoyable’ can feel bloodless, since many of the conversations that matter most in our lives are like this.”