Non-nonverbal communication refers to pure symbolic communication: all nonsymbolic elements (eg, nonverbal, paralinguistic, and extralinguistic) are prohibited. The elimination of nonsymbolic communication from psychiatric interviewing by reducing the number of communication variables simplifies research design. An experiment is described in which 36 judges rated patients on the paranoid dimension using transcripts of non-nonverbal psychiatric interviews as source material. (Machine-mediated interviewing, the method used to obtain the transcripts, effectively prevents all nonsymbolic communication from taking place.) Judges successfully differentiated paranoid from nonparanoid patients and were in agreement 34 out of 36 times.
Hilf FD. Non-Nonverbal Communication and Psychiatric Research. Arch Gen Psychiatry. 1972;27(5):631-635. doi:10.1001/archpsyc.1972.01750290051010