In their landmark article on the topic, Tanya Chartrand and John Bargh state that:
"The chameleon effect refers to nonconscious mimicry of the postures, mannerisms, facial expressions, and other behaviors of one's interaction partners, such that one's behavior passively and unintentionally changes to match that of others in one's current social environment." (Journal of Personality and Social Psychology, Vol 76(6), Jun 1999.)
In a series of rigorously designed experiments Chartrand and Bargh tested the chameleon effect and found:
These seminal findings served to demonstrate the importance of the chameleon effect as a tangible social psychological phenomenon. As the authors note: "It seems unlikely to us that such pervasive, nonconscious effects on social behavior as the chameleon effect arose by accident, and such effects are more likely than not to have positive, desirable effects for the individual and for the groups to which he or she belongs."
Related Body Language Tip:
Verbal mirroring is a simple yet effective way of establishing a connection with someone. Listen to what your conversation partner is telling you, and mirror back the words they use. If someone uses the words “ Happy” “Frustrated” “Embarrassed” “Worried” in their sentences, use those exact words when replying. Mirroring a persons language shows that you understand your conversation partner, and that you are an empathetic listener.