The chameleon effect is the phenomenon that non conscious 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. Essentially, this means that we as humans tend to be “copy cats”. We often mimic others without even thinking about it.
The chameleon effect is very useful in UX design when you know your users. If you know your users well enough, you can use design and language to add a level of familiarity by mirroring some of their behavior back at them and establish a more personal connection between your users and your product.
“Unfamiliar products and interfaces are more difficult to use and can impede adoption.”
-Nir Eyal
In a study published in the Journal of Personality and Social Psychology, of the chameleon effect, Chartrand and Bargh found that students who rated high on empathy were more likely to imitate others. “Those who pay more attention mimic more,” says Chartrand—and make more friends in the process.