There is still much to be discovered about the extent to which humans modulate their voices in social contexts to convey or exaggerate traits that are deemed important – physical strength on the part of men, for example. Researchers of the EU-funded Voice Modulation project have contributed new knowledge in this field. It’s all in the (vocal) presentation “We tested when, how and why men and women altered the non-verbal parameters of their voices – such as voice pitch and timbre – across social contexts,” explains project coordinator Dr Katarzyna Pisanski. Overall, results support the hypothesis that in non-verbal communication, human voice modulation can elicit desirable behaviours and judgments from potential mates, colleagues, friends, superiors or rivals. The project’s longitudinal studies offer additional insight into how vocal parameters change over the lifetime or following critical life events such as puberty and pregnancy. Investigations in this area required recordings of study participants from across the globe, including Finland, Poland, the United Kingdom, Canada, China, Cuba, India, Tanzania and the United States, to ensure the generalisability of the results. One interesting finding is related to men’s voice pitch and reproductive success. Findings suggest that within-individual differences in voice pitch play an important role in human mate choice and competition for mates, and are in fact largely determined before puberty, possibly even in the womb. In another study, Dr Pisanski and her colleagues found that “the mean, range and variation of voice pitch in new mothers lowered significantly following pregnancy … [but] reverted one year postpartum.” Dr David Reby, head of the Sussex Voice Lab, offers that this is likely a combination of hormonal and behavioural (voice modulation) mechanisms. The researchers’ findings also show that people from diverse cultures can modulate their voice frequencies to effectively mimic evolutionarily and socially relevant traits, such as masculinity, physical size and formidability (e.g. strength). People can also change their voices to convincingly mimic various emotional states, particularly through non-verbal vocalisations (e.g. screams, roars and grunts). Although lots of animals produce similar kinds of vocalisations, humans can do this voluntarily. This advanced capacity for vocal control in humans may have set our ancestors apart from other animals, and could have been a key prerequisite for spoken language to evolve. Awareness and impact Project results have been disseminated in published academic research articles, review papers and book chapters, with more under review and in preparation. One of these is a popular science article published in the Atlas of Science. Voice Modulation partners have also presented the project at international and local research conferences, and invited school colloquia, as well as public science exhibitions and outreach events, including the 2017 Royal Society Summer Science Exhibition in London. Leading workshops and seminars plus broad media coverage (traditional and social) also helped to disseminate project work and outcomes. Notably, all project-affiliated publications are open access as is all raw data. Socially relevant and not so different across cultures While some of the data collected during the project is still being analysed and written up, results to date “indicate that voice modulation is a common human behaviour,” Dr Pisanski states. Men and women can modulate their voice pitch and vocal tract resonances on demand (for example to sound physically smaller or larger) and also do so across social contexts, for example on dates and in job interviews. These outcomes “confirm that humans have an impressive degree of volitional control over their voices, not just for speech and singing but also in the context of non-verbal social communication” – an important revelation indicates Dr Pisanski. Study outcomes provide new insight into the rare capacity for deliberate vocal control in humans, strongly supporting that voice modulation may be an effective and universal tool for influencing how we are perceived by others. Such results “obviously have far reaching implications in politics, marketing and telecommunications,” Dr Pisanski concludes. They also provide compelling evidence for the evolutionary origins and advantages of this complex form of vocal behaviour. Project work will continue in certain areas, one of which relates to a custom one-way voice recording mobile application designed by Dr Pisanski. This is used to test whether people alter their voices depending on whom they are speaking to. Through simple screens that appear after a call, the user can easily indicate the call’s nature and their relationship with the listener, allowing Voice Modulation researchers new insight into the social life of the human voice.
Voice Modulation, social contexts, non-verbal communication, speech