Popular Science: The Attractiveness of Our Voice
We humans are not the only one who are able to speak in this world; dolphins and prairie dogs also have their own languages. However, the ability to sing can be found in lots of other species - birds, whales, seals, etc. There is a large quantity of tests that say that singing is important for successful mating across different species. Nevertheless, previous research on voice attractiveness focused only on speech and that is why this scientific group decided to concentrate also on singing.
Singing and speech differ in the use of the vocal system and require a different way of breathing. They also vary in cognitive processing, which can be evidenced by cases of the illnesses called aphasia, in which one loses the ability to speak but is able to sing, and amusia, in which the patient has a disorder of musical ability (is unable to sing, for example) but can speak without problems. Singing also takes more work than speech because it requires more voice control and more muscle activity.
Scientists have studied if singing and speech work as backup signals that can say something about an individual - for example about his body - even though we normally register this kind of information visually. Previous studies found out that speech and singing provide information about gender, emotional state and behaviour. This means that individuals can recognize themselves by speech and singing. The voice can also reveal information about an individual's health and reproductive potential. For example, men with low voices have low cortisol levels and high testosterone levels that are associated with immunoreactivity (the ability of the immune system to defend itself).
On average, men produce lower voices than women: this is because of the effect of testosterone during puberty that lengthens the male vocal cords, thereby reducing the frequency and making the voice deeper. Men with lower voices are therefore perceived as more masculine and dominant than men with higher voices. Similarly, women with deeper voices are seen as more dominant. It was confirmed that both genders with a low voice have more developed leadership abilities. There is also abundant evidence that women prefer men with a deep voice, while men prefer women with a high voice. Attractive male voices are around 96 Hz and the most attractive women voices are up to 280 Hz. Men and women with more attractive voices reported more sexual partners and a younger age for their first intercourse. However, it has recently been shown that even women with low voices are perceived as attractive and women actively lower their voices when flirting with men. In some populations, such as the Philippines, women prefer men with higher voices and men prefer women with deeper voices.
Researchers have therefore decided for the first time to study more populations at the same time. The study tested 81 men and 86 women from Brazil and the Czech Republic. These nations differ in language, history, ethnicity, and they also vary physically, for example in body dimensions such as height and weight. Brazilians also have a higher degree of sociosexuality (the willingness to change partners and establish new relationships). However, the study results haven't shown any noticeable differences between the nations. We can thus speak of a higher generalization, and thus a higher chance that the study's conclusions apply to a larger segment of our planet's population.
The study expected that singing would say more about individual body characteristics and sexuality than speech, but the results showed that speech and singing function equally as backup signals. We perceive the attractiveness of singing and speech in a similar way and it is associated with a higher voice for women and a lower voice for men.
Higher men can boast of a more attractive sound of speech and singing. This is not too surprising. However, it is noteworthy, that the study failed to detect why women preferred the voices of taller men. Men showed no preferences of any height. The lower tone of male speech was linked with higher sociosexuality, but the deeper tone of male singing pointed to lower sociosexuality. It can be explained by the "expensive signalling theory". The pitch of a voice is given by the length of the vocal cords, as most of us speak "economically" - vibrating the vocal cords to their natural frequency. It is much more difficult to vibrate long vocal cords (for example, while singing) to produce high tones than vibrate short vocal cords, whose carriers usually speak with a higher voice. Only the most capable individuals are able to speak naturally in a deep voice and at the same time squeeze out an ecstatic tenor. They will receive the greatest favour of women and a higher score of sociosexuality with it, which positively correlates with the number of sexual partners.
Scientists also measured the VTL (vocal tract length) which corresponds to the length of the whole part of the respiratory tract involved in sound production and if it is measured during voice recording, it can predict body weight. When this variable is put in the model of attractiveness of male voices, body weight also appears as a substantial predictor of voice attractiveness, with only an insignificant part of this effect mediated by VTL itself. It is as if women could “hear” not only the body weight of the evaluated partner but also its “desirable” and “undesirable” part. Body weight can be caused by fat but also by muscles. And because the male body is composed of more muscle than fat, it is possible to consider that voice attractiveness, which is not described by VTL, is associated with muscle mass. According to the authors, further studies should focus on this. The highest SOI (a proxy for potential reproductive success) could be found in women whose voices had a low VTL (like small wind instruments) in speech but were able to turn their voice into a full and powerful VTL pitch (like bassoon or tuba) during singing. Here, too, the expensive signalling theory can offer an explanation. Those who control their voice while singing will receive the deserved attention of members of the opposite gender. However, when listeners only rate speech recordings or singing recordings, this effect may not directly be expressed on the voice's rated attractiveness.
Valentova JV, Tureček P, Varella MAC, Šebesta P, Mendes FDC, Pereira KJ, Kubicová L, Stolařová P and Havlíček J (2019) Vocal Parameters of Speech and Singing Covary and Are Related to Vocal Attractiveness, Body Measures, and Sociosexuality: A Cross-Cultural Study. Front. Psychol. 10:2029. doi: 10.3389/fpsyg.2019.02029