Final answer:
Persuasion is related to the face because the face can convey nonverbal cues that affect a speaker's credibility and likability, which play significant roles in the persuasiveness of a message.
Step-by-step explanation:
According to the authors, persuasion is related to the face because the face is a source of nonverbal cues. These cues include facial expressions, which can enhance a speaker's credibility and likability, thus affecting the persuasive potential of the message. It is well recognized that features such as a speaker's credibility, including their perceived expertise and trustworthiness, alongside their physical attractiveness, significantly contribute to the persuasiveness of the message.
Facial expressions and the general presentation during face-to-face communication provide immediate visual and vocal cues that can influence judgments about a person's conscientiousness, openness, and even extraversion, all of which play a role in peripheral route persuasion. For instance, nonverbal behaviors such as smiling and eye contact can affect a candidate's likability, which, in turn, can influence an interviewer's assessment during a job interview. Furthermore, a more attractive or trustworthy-appearing individual may be more persuasive through both central and peripheral routes of communication as detailed in the Elaboration Likelihood Model of persuasion.