Research has suggested for decades that the sound of a person's voice affects how they are perceived by others, though whether these impressions are accurate hasn't been well established. A new study offers the strongest evidence to date that vocal pitch is predictive of at least some personality traits, such as dominance, extraversion and sociosexuality.

For the study, published March 16 in the Journal of Research in Personality, the authors analyzed 11 different datasets involving more than 2,200 participants in studies focused on different research questions. Personality measures were extracted from self-reported questionnaires and analyzed against voice recordings. Whether the information we pick up from people's voices is truly reflective of their personalities was the core question of the analysis, said Julia Stern, a researcher with the University of Göttingen, in Germany, and the lead author of the paper. 

"When you talk to a person you've never met before, you immediately form some impressions about them," she said in an interview with The Academic Times. "The same thing happens if you talk to that person on the phone: You immediately know whether it's a male or female, how old or how young the person sounds, and whether this is a person you might like or not. Is he or she friendly? We thought it would be interesting to find out if these impressions we form are accurate." 

The researchers found a significant negative relationship between high vocal pitch and traits of dominance, extraversion and sociosexuality, or a willingness to seek out sexual partners outside of a committed relationship. In other words, people with high-pitched voices self-reported those traits less often, while people with low-pitched voices reported them with greater frequency. 

Related research in the field has demonstrated that people's voices measurably affect how they're perceived. For example, people with "gay-sounding" voices face discrimination and anticipate being rejected by others at greater rates, regardless of their sexual orientation, and children's perception of adults' competency in their jobs conforms with gender stereotypes based on whether their voices sound masculine or feminine. 

Literature dating back to the 1930s suggests the existence of a relationship between people's voices and their personalities, Stern said. But most previous studies involved just a handful of participants and lacked rigorous voice analysis. 

"It was mostly, 'This voice sounds deep' or 'This voice sounds high,' with no objective measures," she said. "We were really interested in whether voices and personality were indeed related, because we couldn't rely on these early studies." 

In addition to pitch, the researchers used computer software to measure formant frequency, or the timbre of somebody's voice. They also investigated whether vocal characteristics could be tied to the Big Five personality traits within psychology — openness to experience, conscientiousness, extraversion, agreeableness and neuroticism. 

The study breaks new ground in suggesting that people with high-pitched voices rank higher in neuroticism. "It makes sense, if you think of a person with a higher voice, you probably think, 'This person is more nervous,'" Stern said. "But if it's that obvious, why did nobody investigate it before? That was kind of surprising."

It's unclear whether social or biological factors explain the results overall, Stern explained. It's possible, for example, that the widespread perception of people with low-pitched voices as being more confident and outgoing creates a feedback loop that encourages the adoption of those traits. 

"We don't know whether the causal direction goes one way or another," Stern said. "One possible biological underpinning could be testosterone levels. There are studies that show that testosterone is related to voice pitch and also related to dominance and sociosexuality. Again, it's only correlation; it's also possible that if you have more sexual partners, your testosterone levels rise. But testosterone might be a hormonal mechanism that informs both personality and voice pitch." 

Despite being more rigorous than previous research on vocal pitch and social perceptions, the results are limited in several ways. For one, people's personality traits were self-reported. "Of course, how we perceive ourselves is not the full picture," Stern said. "It would have been better to get ratings from friends or family members."

Additionally, the datasets were sourced exclusively from Western countries, so the findings may not apply to people in other parts of the world. And the voice recordings analyzed in the review weren't standardized; participants were assigned different phrases, which may have affected the pitch of their voices, though probably only minimally. 

Finally, the analysis lacks social context — an area of continuing investigation for the researchers, according to Stern. "If you talk to a child, you may raise the pitch of your voice a little bit," Stern said. "If you talk to your boss, you may talk in a different way than when you talk to your partner. It would be interesting to see how people express their personality in their voice in different social contexts." 

The researchers will seek to answer these lingering questions about the connection between vocal pitch and personality with follow-up studies.

The study, "Do voices carry valid information about a speaker's personality?" published March 16 in the Journal of Research in Personality, was authored by Julia Stern, Lars Penke and Tobias L. Kordsmeyer, Department of Psychology and Leibniz ScienceCampus Primate Cognition, University of Göttingen, Germany; Christoph Schild, Department of Psychology, University of Siegen, Germany; Christoph Schild and Ingo Zettler, Department of Psychology, University of Copenhagen, Denmark; Benedict C. Jones, School of Psychological Sciences and Health, University of Strathclyde, Scotland; Lisa M. DeBruine, Institute of Neuroscience and Psychology, University of Glasgow, Scotland; Amanda Hahn, Department of Psychology, Humboldt State University, California; David A. Puts, Department of Anthropology and Center for Brain, Behavior and Cognition, Pennsylvania State University; David Feinberg, Department of Psychology, Neuroscience and Behaviour, McMaster University, Ontario, Canada; Dan Zamfir, Developmental Psychology and Education, University of Toronto, Canada; and Ruben C. Arslan, Max Planck Institute for Human Development, Germany.