Mirroring the mannerisms of our clients is something that we've been taught to do to increase rapport. I thought it would be useful to look at the scientific evidence that mirroring does indeed increase rapport.
In this 1999 study, there were 72 participants, 37 in the mirroring condition and 35 in the control condition. In a 15-minute session, the participants took turns with another participant who was actually one of the researchers that we call "confederates" to describe photographs. In the mirroring condition, the confederate mirrored the behavioural mannerisms of the participant and in the control condition, the confederate engaged in neutral, nondescript mannerisms.
In the mirroring condition, the participants reported liking the confederate more than in the control condition, and that the interaction between them went more smoothly.
But perhaps the results could have been due to the confederate in the mirroring condition acting in a more friendly manner. The researchers had videotaped a subset of the participants in both conditions and looked at "(a) how much eye contact the confederate made with the participant, (b) how much the confederate smiled at the participant, (c) how friendly the confederate acted toward the participant, and (d) how much the confederate appeared to like the participant.
Once the videotapes were coded by independent judges, they found that there was no difference in the number of these behaviours exhibited by the confederates in the mirroring condition and in the control groups.
So the results, that mirroring increases liking and ease of interaction, are due to the mirroring itself, and not to other "friendly" behaviours that people might exhibit. And only 1 of the 37 participants in the mirroring condition noticed that the confederate had similar mannerisms to them, but they appeared "normal," did not make her feel uncomfortable, and were not interpreted as mirroring. This is a pre-conscious, involuntary response to mirroring that may serve our basic human need to belong.
Two other studies in this paper found that people unintentionally mirror the behaviours of others when they work on a task together, and that more empathic individuals spontaneously mirror more than less empathic individuals.
This study has implications beyond our relationship with our clients. Mirroring skills would be useful in teams to increase team cohesion, to improve relationships between managers/leaders and their reports, and even to better personal relationships. The key to effective mirroring skills is that they appear natural: When people are aware that they are being mirrored, the effect goes away.
Chartrand, T. L., & Bargh, J. A. (1999). The chameleon effect: the perception-behavior link and social interaction. Journal of personality and social psychology, 76(6), 893–910.