Wikipedia
Cyranoids are "people who do not speak thoughts originating in their own central nervous system: Rather, the words they speak originate in the mind of another person who transmits these words to the cyranoid by radio transmission".
The cyranoid concept originated in the late 1970s with psychologist Stanley Milgram, who developed the idea as a means of operationalizing the mind-body fusion fantasy explored in the Edmond Rostand play Cyrano de Bergerac. In the story, Cyrano (a romantic but unattractive poet) supplies Christian (a handsome but inarticulate cadet) with amorous prose so that they may jointly woo Roxane (each being incapable, given their respective limitations, of doing so on their own).
Milgram differentiated the various components of a cyranic interaction: The 'shadower' receives words supplied by a 'source' by-way-of covert audio relay (e.g., discreet radio transmission) and immediately replicates these words using an audio-vocal technique known as speech shadowing. The 'interactant', meanwhile, dialogues face-to-face with the shadower. If successful, the nature of the interaction gives rise to a phenomenon Milgram referred to as the "cyranic illusion," whereby the interactant fails to detect that their interlocutor is merely a speech shadower repeating the words of a remote source.
In his original pilot studies, Milgram explored a variety of cyranic interactions, including a scenario in which panels of teachers interviewed who they believed were autonomously-communicating 11- and 12-year-old children, when in reality Milgram, acting as a source, provided the children with what to say. None of the teachers suspected their interviewees were in fact being controlled by another individual despite the highly sophisticated responses they seemingly produced. Another scenario included multiple sources controlling a single shadower.
Following these studies, Milgram concluded that the cyranoid method held promise as a social psychological research tool, as it allows one to separate the form of a social actor (their physical nature) from the content (words) they produce in interactive social settings. Among other things, therefore, the cyranoid method serves as a means of exploring phenomena such as racial, gender, and age-based stereotyping, as one can dynamically test how a single source is perceived and interacted with differently on the basis of their communicating through a variety of physically-differentiated source-types.
Though initially ignored, researchers have recently begun re-exploring the cyranoid concept in scientific settings. In 2014, Kevin Corti and Alex Gillespie, social psychologists at the London School of Economics, published the first replications of Milgram's original pilots (Milgram himself never formally published his work with the technique). Robb Mitchell has explored cyranoids as an experiential learning tool within the classroom (having children shadow for teachers during teaching exercises). Cyranoids have also been used in installation art to explore social experiences whereby people encounter those familiar to them through the bodies of strangers.