Q: I assiduously avoid the hackneyed use of “feedback” for giving one’s opinion about something, as in this NY Times headline: “How to Give Your Therapist Feedback.” I know that the term can be used to describe the behavior of electrical and other systems. How did “feedback” get its meaning in common parlance?
A: The use of “feedback” for the reaction of people to a product, service, performance, and so on is derived from the term’s earlier use in reference to the output and input signals of an electrical system. That earlier sense also led to the use of “feedback” for the sound distortion produced when the output and input signals don’t get along.
This kind of linguistic evolution is not unusual. Many technical terms have taken on nontechnical senses. Projects as well as trains can be derailed, punches and messages have been telegraphed, the analog computer is gone but not analog people, and politicians as well as actors can take center stage.
When the noun “feedback” first appeared in English in the early 20th century, it referred to the “return of a fraction of the output signal from one stage of a circuit, amplifier, etc., to the input of the same or a preceding stage,” according to the Oxford English Dictionary.
The first OED citation is from the Nov. 27, 1920, issue of Wireless Age: “An inductive feed-back in relation to the secondary system generates local oscillations.”
We found a somewhat earlier example for the term used as a phrasal adjective in a British patent for an electrical signaling system: “One of the variable current sources is a feed-back circuit of the system or a local source of high-frequency current” (Patent GB130432, Aug. 7, 1919).
The sound-distortion sense of “feedback” showed up in the 1930s. The OED defines it as the “effect whereby sound from a loudspeaker reaches a microphone feeding the speaker, thereby distorting the sound, and typically generating a screeching or humming noise.” The dictionary adds that it can also refer to a musical sound “created as a deliberate effect, usually through the amplifier of an electric guitar.”
The OED’s earliest sound-distortion example is from the June 26, 1936, issue of Science: “A button conveniently located on the side is used to turn the instrument [sc. a crystal microphone] on and off after it has been placed in the proper position, thus eliminating much of the problem of feed-back.”
Merriam-Webster Online has an earlier, adjectival example: “Howls, screeches and feed-back microphonic noises which block quality reception have been greatly minimized or totally eliminated in practically all of the new radios now on the market” (Hartford Courant, Oct. 2, 1932).
The earliest Oxford example for “feedback” used in the deliberate musical sense is from the 1960s: “Muddy’s new album Electric Mud is a morass of feedback … reverb and every other trick” (Blues Unlimited, Dec. 10, 1968).
So how did the arrangement of the output and input signals of an electrical system give us a term for positive and negative comments about an activity?
In a word history of “feedback,” Merriam-Webster explains that “negative feedback” originally referred to electronic “feedback that tends to dampen a process by applying the output against the initial conditions,” while “positive feedback” originally referred to “feedback that tends to magnify a process or increase its output.” That apparently inspired the figurative use of “feedback” for positive and negative evaluations.
“Of the several possible meanings of feedback the one that is probably encountered most frequently today (the one meaning ‘helpful information or criticism’) is the most recent,” M-W says. “This sense began seeing use in the 1940s, often found in the field of psychology, and it was over a decade before it crept into the broadened use it currently has.”
The earliest examples we’ve seen are in highly technical articles in scholarly journals from the late 1940s. The social scientist Karl Wolfgang Deutsch, for example, discusses “the feedback notion of consciousness,” and cites “a few suggestive analogies between mechanical or electrical feedback nets, nerve systems, and societies.” (“Some Notes on Research on the Role of Models in the Natural and Social Sciences,” Synthese, January 1948.)
The first OED example for “feedback” meaning a response appeared a decade later: “In … a lecture … the live speaker has a reaction, a ‘feed-back’ from the listeners, and … he can adjust his speech accordingly” (from “Speech Education,” an essay by the linguist J. L. M Trim, in The Teaching of English, 1959, edited by Randolph Quirk and A. H. Smith).
All 10 of the standard dictionaries we regularly check include “feedback” in this sense. Lexico, the former Oxford Dictionaries Online, defines it as “information about reactions to a product, a person’s performance of a task, etc. which is used as a basis for improvement.” Here’s one of the dictionary’s many examples: “Individuals want feedback on their performance and it is also crucial to their self-development.”