Scientists from the University of California, Irvine and the University of Utah have investigated what makes a human voice attractive, a question with important implications in both our personal and professional lives.
The researchers recorded 42 individuals performing a variety of speech tasks and asked participants to rate the vocal attractiveness of the recorded speakers. They studied how acoustic correlates of speech clarity might predict attractiveness ratings, with the concept of “vowel space area” (an important qualitative intelligibility index) as a main acoustic feature.
“Much received wisdom and many vocal coaches would encourage people to slow down and carefully enunciate to make a better impression on their audience,” said study co-author Daniel Stehr.
“However, when it comes to empirical studies of how attractiveness of the human voice is judged, we couldn’t find previous work investigating whether an actual link exists between perceived attractiveness and overall clarity of articulation.”
Stehr and his colleagues were surprised to discover an important gender difference for the correlation between speech intelligibility and perceived attractiveness. Although clarity of articulation seemed to be strongly predictive of vocal attractiveness, these results only applied to female speakers.
Scientists believe that the lack of relationship between acoustic correlates of clearly produced speech and male vocal attractiveness might have compelling evolutionary origins.
“From a sexual selection standpoint, males with traits that are slightly more masculine than average are typically preferred, which in this context would make males with less clear speech more attractive,” Stehr explained.
However, such theories should not be taken for granted. As Stehr acknowledged, everything connected to evolution can have different, sometimes even contradictory, explanations.
“At the same time, constricted vowel space area and lower perceived clarity is associated with a range of speech motor disorders, suggesting a lack of clarity may also have indicated the presence of disease to our ancestors,” said Stehr.
Further research is needed to sort through such contradictory explanations, and shed more light on the evolutionary origins of contemporary human behaviors.
The study was published in The Journal of the Acoustical Society of America.