The Nonverbal Dictionary of Gestures, Signs & Body Language Cues, from Adam’s-Apple-Jump to Zygomatic Smile, by David B. Givens (Spokane, Washington: Center for Nonverbal Studies Press), is a detailed examination of the ways we communicate without words. Take “zygomatic smile,” for instance:
Usage: Though we may show a polite grin or camera smile at will, the zygomatic or heartfelt smile is hard to produce on demand. While the former cue may be consciously manipulated (and is subject to deception), the latter is controlled by emotion. Thus, the zygomatic smile is a more accurate reflection of mood.
Anatomy. Lip corners curl upward through contraction of zygomaticus muscles; crow’s-feet show when the zygomaticus muscles are strongly contracted, and/or when orbicularis oculi muscles contract. In the polite (i.e., intentional, weak, or “false”) smile, lip corners stretch sideward through contraction of risorius muscles, with little upward curl and no visible crow’s-feet.
Evolution. The smile-face may be traced to the primate’s grimace or fear grin. The submissive grin, used to show “I am afraid,” came to suggest that “I am harmless—and therefore friendly—as well” (Morris 1994). The link between smiling and humor, love, and joy has yet to be explained.
Feedback smile. Smiling itself produces a weak feeling of happiness. The facial feedback hypothesis proposes that “…involuntary facial movements provide sufficient peripheral information to drive emotional experience” (Bernstein et al. 2000). According to Davis and Palladino (2000), “…feedback from facial expression [e.g., smiling or frowning] affects emotional expression and behavior.” In one study, e.g., participants were instructed to hold a pencil in their mouths, either between their lips or between their teeth. The latter, who were able to smile, rated cartoons funnier than did the former, who could not smile (Davis and Palladino 2000).
That’s less than half the entry, which goes on to discuss Peter Jennings, Dr. Irving Smigel (a New York dentist who created the Supersmile product line), the “supermarket mandatory smile,” salesmanship, and the smiley face, as well as providing a list of “research reports.” And there’s much, much more; the book is a real treasure trove. (Via dublog.)