Review of Psychology

Cues That Are Seen

Social categorization is a fundamental aspect of human cognition. The potential informational value of various sender cues is thus an important line of basic research within the domain of nonverbal encoding. It also is important to both traditional (e.g., psychiatric diagnoses) and emerging (e.g., biometrics and human–robot interactions) domains. During interactions, senders nonconsciously encode information about themselves that is more or less static (e.g., markers), such as their identity, biological sex, psychological and developmental problems, and social and personality attributes. These markers likely emerge as a consequence of genetic, biological, developmental, and learning factors, among others. In this section, we discuss illustrative cues that are visible to an actual or potential perceiver and that have potential informational value as markers for social categorization. The potential value of cues is stressed because the meaning of any cue or set of cues is probabilistic at best and may hinge on a host of other encoded cues, sender characteristics, perceiver qualities, and contextual and situational factors, as stated above. This aspect of nonverbal encoding is covered in the section titled Cues That Are Heard.
Individual identity. Senders’ unique identities can be communicated via a number of nonverbal channels, including their gait (Takemura et al. 2018), the iris of the eye (Sibai et al. 2011), and body odor (Rodriguez-Lujan et al. 2013). For example, Rodriguez-Lujan et al. (2013) provided evidence that hand odor may serve as a biomarker of identity. However, much of this research is situated in the computer science domain of biometrics; its generalizability to everyday person identification among humans is therefore unclear.