What happens to the voice when dialogue partners find the other person attractive? And what effect does sympathy have? A study with Oldenburg students has provided linguists Jan Michalsky and Heike Schoormann with initial answers.
Whether Siri, Alexa or Google Assistant - communicating with technical devices via voice is becoming more and more normal in our everyday lives. The fact that voice assistants are sounding increasingly human is also thanks to findings from linguistics. In order to make the voices of technical "assistants" as natural as possible, it is also important to understand how social parameters are reflected in speech behaviour. For example, whether and how does the speaker's voice change if they find the person they are talking to attractive or likeable? This is precisely what the Oldenburg linguists Dr Jan Michalsky and Heike Schoormann have investigated. Their findings: likeability and attractiveness have an effect on the pitch of the voice, among other things.
New approaches in research
The two young researchers drew inspiration for their research from the animal kingdom. There, the vocalisations of animals and, above all, the pitch, i.e. the frequency, play a central role: larger animals generally have a lower fundamental frequency, smaller animals a higher one; those who demonstrate power in a fight lower their fundamental frequency - those who submit raise it. Wolves make use of this behaviour during courtship and in territorial fights in order to appear as strong as possible.
For a long time, experts believed that similar principles apply to humans. However, the results of recent studies are contradictory: "We still don't really know what makes a voice attractive," says Michalsky. However, new scientific methods have given research a boost: current studies focus on investigating vocal behaviour in real conversational situations.
Study with Oldenburg students
Michalsky and Schoormann are also pursuing this approach - investigating vocal behaviour in spontaneously spoken language. However, they are not interested in what makes an "attractive voice", but in how the "attracted voice" reacts: What happens to a person's voice when they speak to someone they find attractive?
To find out, the two researchers invited Oldenburg students to take part in speed dating - ten men and ten women. The scientists recorded a total of 100 conversations, each lasting 15 to 20 minutes. Before and after the conversation, the test subjects had to rate how attractive and likeable they found the other person on a scale of one to ten. Michalsky and Schoormann then analysed the conversations. In doing so, the linguists broke new ground: "We assumed that there was already a broad research base on this. But we found surprisingly little in the literature," says Michalsky.
In the audio recordings, the researchers first looked for changes in the voice throughout the entire conversation. The so-called "synchrony effect", for example, was confirmed: the pitch of the speaker's voice is aligned with that of the interlocutor - the voices thus maintain a certain distance from each other. According to Michalsky, this behaviour is directly related to the perceived likeability of the test subjects.
Different effects
If, on the other hand, the speaker finds the other person particularly attractive, this is reflected in the raising or lowering of the fundamental frequency. This effect is particularly noticeable when there is a change of speaker. "The more attractive a man finds his conversation partner, for example, the lower he tends to start," Michalsky explains. However, he then returns to his original pitch after a maximum of 15 seconds. The exact opposite happened with the women in the study: the moment the man gave up and they picked up the conversation again, the pitch of the voice tended to rise - depending on how attractive the woman found her conversation partner. The voice then returned to its original pitch.
If the conversation partners find each other attractive, their voices initially move away from each other. As the conversation progresses, this effect weakens again - the researchers conclude that creating a certain impression seems to be particularly important at the beginning of a conversation. They also found that the pitch of two people's voices converge over the course of the conversation. The more attractive the two people find each other, the greater the convergence effect.
Sympathy and attractiveness are thus manifested in speech behaviour through different effects: by the voices keeping a relative distance from each other or moving towards each other. However, these effects can also occur in parallel, according to Michalsky: "Synchrony and convergence can occur simultaneously. This means you can become more similar and still move along."
A topic with a future
Due to the small, non-representative sample, it is not yet possible to draw any generalised conclusions from the study. However, the results have met with interest in the linguistic community: "We had the right idea at the right time," says Michalsky. Together with colleagues from Denmark, he is working on a proposal for a larger research project. While the study has so far focussed on heterosexual singles, the phonetician would like to include other groups of people such as couples or homosexuals in the future. The personality profiles of the candidates will also be included in the analysis.
The fact that the results of the study can also be of use outside of science - not only to optimise language assistants but also for speech therapy purposes, for example - pleases the scientists: "This allows you to step out of the ivory tower of science - that's nice," says Schoormann.