Star Trek: 10 Things You Didn't Know About Tricorders

This isn't the name of a bloodthirsty sentient tricorder that will stab you in the shower, it's an offshoot of the medical model that only ever featured in one episode of The Original Series — Wolf in the Fold. The psycho-tricorder, as seen in that episode, was also just a standard tricorder prop.

Capable of scanning and recording memories, and of psychological examination more generally, the psycho-tricorder could be operated by a medical technician, although they might get killed by Jack the Ripper before they can get to the bottom of any "hysterical amnesia". The psycho-tricorder has appeared in a smattering of beta-canon works; in the TOS Mudd's Angels short story The Business, As Usual, During Altercations, we even get a 'psychohistorian' with a psycho-tricorder, but that's about it.

It is possible that the functions of the psycho-tricorder were later incorporated into the standard medical tricorder or made redundant by other techniques. In the Star Trek: Voyager episode Night, The Doctor uses a medical tricorder to help diagnose Neelix's anxiety attacks as 'nihiliphobia' ("the fear of nothingness").