Voice:

Sally D. Farley, Susan M. Hughes, Jack N. LaFayette:

>As social animals, we are intuitively attuned to the emotional states of those who surround us. Many have argued for the importance of vocalic cues for the expression of our emotional states (Burgoon et al. 2010; Scherer 1986, 2003). In relational communication, our ability to correctly differentiate between angry, fearful, or elated tones of voice is essential to relational harmony and stability. For example, research has linked accurate vocal nonverbal communication to measures of marital satisfaction (Noller 1980). A number of findings are consistent with the notion that our voices evolved as effective communication devices beyond relaying semantic information through speech. Scherer’s (1986, 2003; Banse and Scherer 1996) theoretical work on vocal affect expression argued that different emotional states are expressed using unique vocal profiles. This emotional differentiation in voice is similar to the differentiation seen in facial expression (Scherer 2003; Ekman 1993). ...

Using voice as our primary mode of communication affords us many advantages; it allows us to communicate over appreciable distances without having to be in direct contact with the listener, and the production and reception of vocalizations are not dependent upon light. Beyond what the content of speech communicates, the ability to use intonations, inflections, whispers, and otherwise change the overall sound of our vocalizations allows for even further transmission of information (Gallup and Cameron 1992). 

From an evolutionary standpoint, vocalizations are an important channel for survival (Floyd and Ray 2003). One interesting illustration of this logic is the specialized alarm calls emitted by capuchin monkeys in response to terrestrial versus arboreal predators (Fichtel et al. 2005). Another evolutionary theory that argues for the critical value of recognizing affection displays in others is termed affection exchange theory (AET) (Floyd et al. 2008). AET posited that successful use of nonverbal cues to signal affection and connectedness to others offers individuals a survival advantage. Consequently, it is not surprising that individuals show great skill at encoding and decoding various signals of affection such as behavioral synchrony (Capella 1997; Karremans and Verwijmeren 2008), touch/haptics (Guerrero 1997; Koeppel et al. 1993) and vocalic cues. We may attend to vocal cues of romantic interest to avoid expending energy on individuals who are unavailable, such as those who are already in monogamous relationships, or those who are simply not interested in us. Consistent with this logic, research has indicated that listeners can detect sexual orientation with greater than chance accuracy through voice alone (Munson et al. 2006). Like other nonverbal behaviors, vocal cues are not only used to communicate connectedness and intimacy with our loved ones, but can also act as signals to others about our relationship status (Burgoon et al. 2010). The modification of the sound of a person’s voice appears to be of particular importance when it comes to romantic relationships. Several studies point to evidence that individuals manipulate the sound of their voices in order to attract potential mates. For instance, in an experimental ‘‘seduction’’ study, men who engaged in greater vocal modulation were more successful at obtaining a second date with their female partners (Anolli and Ciceri 2002). In addition, Hughes et al. (2010) found that both men and women lowered the pitch of their voices when speaking with an attractive member of the opposite sex (in order to sound more attractive) as opposed to an unattractive member of the opposite sex. Furthermore, independent raters assigned higher pleasantness ratings to voice samples directed toward attractive targets than unattractive targets (Hughes et al. 2010).<