The human face can be seen as a complex, characteristically unique pattern that helps us distinguish people (Vezjak and Stephancic 1994). Faces, in general, are involved in reproductive behavior among humans. Couples faces resemble each other much more than random pair formation would suggest. Similarities between faces are not likely to arise as a result of pair formation or environmental factors (Rice and Borecki 2001), as facial features have a strong genetic basis. Facial resemblance between couples has been extensively reviewed (Penton-Voak and Perrett 2000) and can certainly be viewed as an adaptive trait produced from evolutionary forces. Human faces are even considered as a communication device for signaling heritable traits (Thornhill and Gangestad 1999) and aid in the search for mates with “good genes”.
Facial expression is a universal form of communication among mammals. This silent communication system is made possible by the fact that facial muscles are the only muscles in the body that attach directly to the skin, which allows for infinite subtleties of expression. Body language is nearly as expressive, with its infinite variety of attitudes to display emotion. At least on a basic level, most people recognize that what you say is often far less important than how you say it. And how you say it involves powerful and complex messages sent by facial expression, body language, tone of voice, and even scent. Making this all the more difficult is the fact that much of this communication takes place beyond the reach of our conscious awareness. The explanation for feelings of comfort and uncomfortable lies in the complex communications transmitted through facial expression, body language, and other unconscious physical signals, including smell. As you look up the evolutionary ladder, one finds an increasing tendency among mammals, especially in primates, to mimic one another. This is done unconsciously and automatically as a means of communication. We signal our emotional states externally through facial expression and other forms of body language, such as posture. Seeing these unconscious signals in another individual initiates an involuntary need to mimic such behavior.
When two individuals send information through this subconscious communication system, they not only catch each other’s emotional state, but their heart rates, breathing, speech patterns, and skin conductance all synchronize as well. Studies using high-speed cameras demonstrate how this system works. Complete shifts in facial expression, from a happy smile to a horrified grimace and back to a smile, can take place within a fifth of a second, too quickly to register in our conscious minds. Two people who are communicating in this way will synchronize their speech patterns and rhythms within as little as a 20th of a second. When it comes to men and women interacting like this, the effects can be profound, and virtually irresistible. In one experiment, psychologists paired men and women and told them to gaze into each other’s eyes for 2 minutes. As potential lovers become comfortable, they pivot or swivel until their shoulders become aligned, their bodies face-to-face. When he crosses his legs, she crosses hers; as he leans left, she leans left; when he smoothes his hair, she smoothes hers. They move in perfect rhythm as they gaze deeply into each other’s eyes. Afterward, they experienced greater feelings of romantic love, attraction, interest, warmth, and respect than control groups felt. These results are more interesting considering conversation was not involved in the experiment. Called interactional synchrony, this human mirroring begins in infancy. By the second day of life, a newborn has begun to synchronize its body movements with the rhythmic patterns of the human voice. And it is now well established that people in many other cultures get into rhythm when they feel comfortable together.