Re: feedback

Dan Clemmensen (
Mon, 22 Sep 1997 18:25:00 -0400

Damien Broderick wrote:
> `Negative feedback' is *not* primarily an economics term, but derives from
> systems and control theory and has very general application. It is at
> least 50 years old, and is the basis of all advanced control systems.
> Perhaps it is called something entirely different in your own language, but
> it is defined in most English dictionaries. I keep a dictionary on my
> desk, and another on my kitchen table, and when I see a word I don't know I
> look it up - I don't start by asking other people. If it's not in the
> dictionary, I look in the encyclopedia in my study, and if it's not there
> *then* I have no hesitation in asking.

To which I would add: perform an Alta Vista search on
the term before asking a question of a live human. This
is sometimes easier than standing up and walking all the
way over to your dictionary. There are also dictionaries
on the web, but the search can often be more helpful.
Try "negative feedback".

> The term is regularly abused in the general English-speaking culture. New
> Age types, and many others, are always smiling gratefully when they receive
> what they call `positive feedback' (meaning, for them, encouragement or
> praise) and recoiling from the dreaded `negative reinforcement' (meaning,
> they suppose, disapproval). In fact, positive feedback is nothing more
> than returning a part of the system's output in such a way that the output
> *increases*, while negative feedback uses part of the system's current
> output to *restrict* or *lower* continuing output.

I had the pleasure of being in an auditorium in which
a marketing type asked an audience of engineers for
"positive feedback" just as he moved in front of the
speaker while wearing a portable microphone. He got
his positive feedback then, from the PA system. The
Audience cracked up, laughing uproarously. The marketeer
got a puzzled look on his face.

Population growth, epidemics, and our singularity scenarios
are examples of positive feedback. The non-technical public
just doesn't get it.