Mirroring, or the chameleon effect, is the behavior in which one person subconsciously imitates the gesture, speech pattern, or attitude of another. Mirroring often occurs in social situations, particularly in the company of close friends or family, often going unnoticed by both parties. The concept often affects other individuals' notions about the individual that is exhibiting mirroring behaviors, which can lead to the individual building rapport with others.

Mirroring is distinct from conscious imitation under the premise that while the latter is a conscious, typically overt effort to copy another person, mirroring is unconsciously done during the act and often goes unnoticed.

The display of mirroring often begins as early as infancy, as babies begin to mimic individuals around them and establish connections with particular body movements. The ability to mimic another person's actions allows the infant to establish a sense of empathy and thus begin to understand another person's emotions. The infant continues to establish connections with other individual's emotions and subsequently mirror their movements.

Mirroring can establish rapport with the individual who is being mirrored, as the similarities in nonverbal gestures allow the individual to feel more connected with the person exhibiting the mirrored behavior. As the two individuals in the situation display similar nonverbal gestures, they may believe that they share similar attitudes and ideas as well. Mirror neurons react to and cause these movements, allowing the individuals to feel a greater sense of engagement and belonging within the situation.

Mirroring generally takes place unconsciously as individuals react with the situation. Mirroring is common in conversation, as the listeners will typically smile or frown along with the speaker, as well as imitate body posture or attitude about the topic. Individuals may be more willing to empathize with and accept people whom they believe hold similar interests and beliefs, and thus mirroring the person with whom one is speaking may establish connections between the individuals involved.

In prehistory, following another person's lead would have resulted in positive outcomes during life-or-death circumstances, namely staying still near a wild animal that could either be a predator or be hunted. The chameleon effect occurs when people hang out with their friends. During a conversation, a person may reflect their friend's posture and facial expression, and such mirroring may positively influence the interrelationship as it leads them to believe that they have similarities and are in sync with one another.

Additionally, mirroring may play a role in how well an individual fares in a job interview. Within a study conducted by Word, Zanna and Cooper, interviewers were instructed to follow specific types of body language in different experimental conditions. In one condition, interviewers were instructed to demonstrate distant and uninterested body language (such as leaning away or avoiding eye contact), and in another condition, they were asked to demonstrate more welcoming body language (such as smiling and making eye contact). As a result, the individuals being interviewed began to mirror the actions of the interviewer, and thus the individuals in the condition with less friendly body language fared worse within the interview than did individuals in the friendly condition. The study demonstrates that the initial attitudes that an interviewer may have of the individual being interviewed may affect the performance of the interviewee due to mirroring.

Individuals with autism or other social difficulties may be less likely to exhibit mirroring, as they may be less unconsciously and consciously aware of the actions of others. This factor may cause additional difficulties for the individuals, as without mirroring, establishing connections with other people may be more difficult. Additionally, other individuals may be less likely to build rapport with the person, as without mirroring the person may seem more dissimilar and less friendly. Individuals who are not unconsciously aware of the gesture may have difficulties in social situations, as they may be less able to understand another person's perspective without it being explicitly stated, and thus may not understand covert cues that are often used in the social world. It is possible for autistic individuals to deliberately learn and become aware of these cues.