Human voices are produced in the throat, with sound generated by the vibration of the vocal cords, and the frequency of these vibrations, known as the fundamental frequency (F0), plays a key role in the characteristics of the voice. Additionally, the resonant frequencies of the vocal tract create what are known as formants. These two parameters—F0 and formant frequencies—are often studied as potential indicators of gender differences. Research has shown that F0 and formants can reveal important social information, and that voice pitch is related to a person’s testosterone levels, although some studies have found little or no correlation between voice characteristics and testosterone. Still, differences in voice pitch and formants between men and women may be influenced by varying testosterone levels.
According to sexual selection theory, gender differences evolve through two main mechanisms: intra-sexual competition (competition within the same sex) and inter-sexual selection (mate choice between sexes). Inter-sexual selection suggests that female mate preferences, such as a preference for lower-pitched male voices, evolve as females select mates based on traits that signal strength or dominance. Interestingly, this preference for lower-pitched voices is particularly strong in women during their fertile period, close to ovulation.
In contrast, intra-sexual competition focuses on male competition for dominance, often through higher leadership skills or persuasive abilities, and higher dominance is linked to more access to resources and potential mates. This dynamic suggests that voice differences between the sexes may be influenced by both female mate selection and male competition for status.
Until recently, no studies had investigated whether a person’s voice pitch could predict their intention to be unfaithful or their level of commitment in a relationship. However, a study published in Personality and Individual Differences titled "Vocal Characteristics Predict Infidelity Intention and Relationship Commitment in Men but Not in Women" explored this very idea. Researchers from Sichuan University and Southwest University in China found that vocal characteristics could help predict men’s willingness to cheat and their commitment to a relationship, but the same was not true for women.
In this study, the researchers analyzed three vocal parameters in participants: the fundamental frequency (F0), the standard deviation of F0 (F0-sd), and the formant frequency (Pf). They used self-reported surveys to explore the relationships between these voice parameters and individuals' intentions to be unfaithful and their commitment to their relationship. The results showed that, in men, F0 and F0-sd were negatively correlated with their intention to be faithful (i.e., lower-pitched voices were associated with greater likelihood of infidelity), while being positively correlated with relationship commitment. However, Pf showed no significant correlation with either infidelity or relationship commitment in men.
For female participants, on the other hand, voice characteristics did not appear to predict infidelity or relationship commitment. The study concluded that, while voice features might help predict male behavior in terms of infidelity and commitment, they were not as useful for understanding female relationship dynamics.
Researchers noted that men typically have lower F0 and formant frequencies, which are often associated with higher attractiveness and dominance. Men with deeper voices are often seen as more authoritative and capable of leading, which may influence their social standing. Furthermore, people tend to view men with lower-pitched voices as more reliable. Interestingly, other studies have suggested that men with higher-pitched voices may also be seen as more trustworthy. These contradictory findings likely reflect the context in which trust is being assessed, as in romantic relationships, lower-pitched men and higher-pitched women are often perceived as more likely to engage in infidelity.
The study also found that unfaithful men typically report lower relationship satisfaction and exhibit lower intimacy and commitment to their partners. Women, too, tend to perceive men with low-pitched voices as less likely to invest time and energy into their relationships, and they might assume these men are less generous financially as well.
Testosterone is known to influence both physical characteristics and behaviors, including those related to infidelity. Higher testosterone levels in men are associated with a greater likelihood of extramarital affairs, and men with high testosterone levels tend to have more affairs and less stable relationships. Similarly, high estrogen levels in women have been linked to a higher likelihood of infidelity and more extramarital partners. Research also suggests that higher testosterone levels can negatively impact marital satisfaction, as men with high testosterone are less likely to engage in behaviors that nurture romantic relationships, leading to a higher divorce rate.
In this study, the researchers found that men with lower-pitched voices (which are often associated with higher testosterone) were more likely to exhibit infidelity and invest less in their relationships. This behavior was not observed in women, highlighting a potential gender difference in how voice pitch relates to relationship behaviors.
The researchers acknowledged several limitations to their study. First, the participants were college students within a narrow age range, and their relationships were relatively short-term. As relationships mature and as individuals transition into adulthood, factors influencing infidelity and commitment may change. Further research is needed to replicate these findings with more diverse samples and longer-term relationships.
Second, the study was based primarily on Western cultural contexts, and there is limited research on the vocal characteristics of Chinese participants. Though the researchers calculated vocal parameters based on five standardized neutral words, these parameters were influenced by Mandarin tonal characteristics, which may differ from other languages. Future studies should explore other forms of vocal data, such as vowel sounds, to obtain a clearer picture.
Third, while the study indirectly inferred the role of hormones by examining voice parameters, it did not measure participants' actual testosterone levels. Future research will benefit from directly measuring hormone levels to better understand the link between testosterone, voice pitch, and relationship behaviors. Lastly, the study assessed participants' intentions toward infidelity rather than actual infidelity behaviors, and further research should focus on actual behavior in relationships to better understand how voice pitch influences fidelity.
The findings of this study suggest that, for men, vocal characteristics—particularly lower-pitched voices—can be a predictor of both infidelity and lower relationship commitment. This may be due to hormonal influences, particularly testosterone, which also affects behaviors linked to relationship dynamics. However, these patterns do not seem to apply to women in the same way. The study underscores the importance of understanding the role of voice in relationship maintenance and calls for further research to explore these dynamics more deeply, especially in different cultural contexts.
