Nineteenth-century British writer and aphorism documentarian Charles Caleb Colton ushered the phrase "Imitation is the sincerest form of flattery" into common usage in 1820 [source: Martin]. Come to find out, Colton's adage applies quite well to interpersonal attraction. When people interact in dating scenarios, and things are going well, body language mirroring often happens subconsciously. For instance, someone will lean in close to the dinner table, and other person follows in suit.
Better yet, without knowing it, these subtle gestures also serve to stoke each other's romantic egos. A 2009 study on mimicry in a speed dating environment revealed that men gave more favorable ratings to women who slightly mirrored their verbal and nonverbal patterns [source: Gueguen]. Scratching their faces after the men scratched their faces, for instance, ultimately increased the women's sexual attractiveness after the 5-minute interaction [source: Jarrett]. If that body language exchange sparks a long-lasting relationship, men's and women's bodies tend to play copycat as they age together as well. According to a 2006 study, the longer couples stick together, well after the jittery symptoms of attraction have calmed, the more they physically begin to look alike [source: Silverman].