Monday, June 27, 2022

It's all about negative feedback

The question is posed: Is negative feedback good or evil?
Answer: Good!
Yes, 'negative' is good.

Ooops: did I mention what feedback is? Generally it is a sample or portion of an outcome, or something directly related to an outcome.

Here's the thing: 'Positive' feedback is reinforcing, agreed, but that may not be a good thing. 
Really? Why not?
Because positive feedback encourages or promotes outcomes to ever increase, following the rule: 'more is better'. But such may become unstable, erratic, even chaotic. And, if the outcome has elements of distortion, disturbance, or some other impurity, then rather than 'more' you want 'less'.   

Negative feedback -- which is to be understood as feedback phased or timed to be not reinforcing -- helps with stability, predictability, and puts a damper on chaotic impulses. Done right, properly phased feedback can reduce distortion and help cancel-out disturbances. (*)

We can summarize this way: 
The primary purposes of 'feedback' are to: 
  • correct behavior (not always, or even mostly, human behavior), 
  • prevent 'runaway' and chaotic responses, 
  • confirm outcomes as expected, and 
  • enhance the predictability of outcomes. 
These latter advantages come from so-called 'negative' feedback.

NOTE: providing feedback has its own jargon: We say: feedback closes the loop (the loop is from outcome back to the source that drives the outcomes), or the 'loop is closed'

Now the tricky part: Strength and timing are everything. 
To close the loop effectively, the strength (or amplitude) of feedback, and the timing (or phasing) of feedback has to be such that the feedback provides a countermeasure to the potentially errant outcome, the net effect being an outcome just as predicted, void of the bad stuff.
What could possibly go wrong?
Actually, a lot can go wrong.

No feedback at all is the worst of the worst: the 'system' is 'open loop', meaning that there are outcomes that perhaps no one (or no thing) are paying attention to. Stuff happens, or is happening, and who knows (or who knew)?

Timing errors are perhaps the next worst errors: if the timing is off, the feedback could be 'positive' rather than 'negative' such that the 'bad stuff' is reinforced rather than damped down. 

Strength errors are usually less onerous: if the strength is off, but the timing is on, then the damping may be too little, but usually you get some favorable effect

Practical project management
Feedback for correcting human performance is familiar to all. Too late and it's ineffective; too much over the top and it's taken the wrong way. So, timing and strength are key

But, the next thing is communication: both verbal and written (email,etc). Closing the loop provides reassurance of the quality and effectiveness of communication. You're just not talking or writing into the wind!

And, of course, in system or process design, loops should never be open. Who knows what could happen.

I should mention:
The study of feedback systems generally falls within what is called 'cybernetics'. As described by, MIT mathematician Norbert Wiener defined cybernetics as “the study of control and communication in the animal and the machine." 

From Wikipedia, we learn: The core concept of cybernetics is circular causality or feedback—where the observed outcomes of actions are taken as inputs [ie, feedback] for further action in ways that support the pursuit and maintenance of particular conditions [ie, 'ways that support' requires the correct timing and strength]

(*) The difference between noise and song among many voices is timing or phasing. The members of a really good choir or ensemble sense the others and with that feedback each member adjusts to the pace of the others. But, get the timing wrong, and it's all just noise. 

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