FEEDBACK LOOPS
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A SYSTEMS THINKING TOOL
By: Alan Ticotsky  |  2/14/2014

Most of us are familiar with feedback in several contexts.  If you hold a microphone too close to a speaker, the amplified sound is picked up by the microphone and transmitted back to the speaker, where it is broadcast to the microphone again, and pretty soon ... ouch!  Cover your ears.

Another example of feedback occurs when a person observing behavior provides information and opinion to another person.   That feedback may cause a change in the behavior, which can be observed again and further analyzed.

In systems thinking,  which deals with changes over time and the causal elements that drive those changes, feedback has a special but similar meaning.  Feedback is identified as a loop mechanism. 

Here's a definition of feedback loops from Jack Harich:
"Feedback loops control a system’s major dynamic behavior. A feedback loop is a series of connections causing output from one part to eventually influence input to that same part."
TWO KINDS OF LOOPS
  1. Think about a performance improvement loop, or virtuous circle.  Practice some skill, such as playing music or athletics, and we get better.  When we get better, we can perform at a higher lever, and we can get even better.  Unfortunately, vicious cycles exist also, like inflation.  Prices go up, so workers negotiate higher wages.  Higher wages increase buying power, but companies raise prices as it becomes more expensivve to produce goods, partly because of increased wages.  In systems language, these up or down spirals are called reinforcing loops.
  2. Let's look at performance in a different way.  What if I don't care about getting better at my lessons?  But my parents care and apply pressure to me.  So I practice and I get better. Once I satisfy them however, I can back off on practicing.  Then my skills begin to erode. That makes my parents react, so I have to increase practice again. I stay with this oscillating pattern, practicing enough to keep my parents off my case, but not working so hard that I forego other activities I'd rather do.  This "wave-like" pattern is a balancing loop.  A thermostat is a good example of a balancing loop in our everyday life.  Heating or cooling is called for when a certain temperature criterion is passed.  Once it is met, the machine doing the work shuts off, until the measure of heat in the room turns it on again .
Connection circles and causal loop diagrams are the systems tools we teachers and students use to represent feedback thinking in our learning.  At IACS, applications of feedback thinking have been developed and applied in most content areas.  Many educators believe feedback tools can help boost reading comprehension and support some major goals of the Common Core Standards.

Professor Jay Forrester of MIT, often considered the founder of system dynamics (quantitative branch of systems thinking), describes feedback thinking in the excerpt below: