Changes

[[File:lighterstill.jpg]][[File:Globewatervapor_larger.jpg|right|frame]]

[[File:lighterstill.jpg]][[File:Globewatervapor_2b.jpg|right|frame]]

 

'''Feedback''' describes the situation when output from (or [[information]] about the result of) an [[event]] or [[phenomenon]] in the past will influence the same event/phenomenon in the present or future. When an event is part of a chain of [[Causality|cause-and-effect]] that forms a [[circuit]] or loop, then the event is said to "feed back" into itself.

'''Feedback''' describes the situation when output from (or [[information]] about the result of) an [[event]] or [[phenomenon]] in the past will influence the same event/phenomenon in the present or future. When an event is part of a chain of [[Causality|cause-and-effect]] that forms a [[circuit]] or loop, then the event is said to "feed back" into itself.

*Feedback loop; the causal path that leads from the initial generation of the feedback signal to the subsequent modification of the event.

*Feedback loop; the causal path that leads from the initial generation of the feedback signal to the subsequent modification of the event.

*Audio feedback; the special kind of positive feedback which occurs when a loop exists between an audio input and output.

*Audio feedback; the special kind of positive feedback which occurs when a loop exists between an audio input and output.

==Overview==

==Overview==

Feedback is a [[mechanism]], [[process]] or [[signal]] that is looped back to control a [[system]] within itself. Such a loop is called a feedback loop. [[Intuitively]] many systems have an obvious input and output; feeding back part of the output so as to increase the input is positive feedback; feeding back part of the output in such a way as to partially oppose the input is negative feedback.

Feedback is a [[mechanism]], [[process]] or [[signal]] that is looped back to control a [[system]] within itself. Such a loop is called a feedback loop. [[Intuitively]] many systems have an obvious input and output; feeding back part of the output so as to increase the input is positive feedback; feeding back part of the output in such a way as to partially oppose the input is negative feedback.

When feedback modifies an [[event]]/[[phenomenon]], the modification will subsequently influence the feedback signal in one of three ways:

When feedback modifies an [[event]]/[[phenomenon]], the modification will subsequently influence the feedback signal in one of three ways:

*1 - the feedback signal increases, leading to more modification. This is known as posithttp://nordan.daynal.org/wiki/skins/common/images/button_link.png[[Link title]]ive feedback.

*1 - the feedback signal increases, leading to more modification. This is known as posithttps://nordan.daynal.org/wiki/skins/common/images/button_link.png[[Link title]]ive feedback.

*2 - the feedback signal decreases, leading to less modification. This is known as negative feedback.

*2 - the feedback signal decreases, leading to less modification. This is known as negative feedback.

*3 - the feedback signal does not change, indicating the phenomenon is in equilibrium.

*3 - the feedback signal does not change, indicating the phenomenon is in equilibrium.

The terms negative and positive feedback can be used loosely or colloquially to describe or imply [[criticism]] and [[praise]], respectively. This may lead to confusion with the more technically accurate terms positive and negative reinforcement, which refer to something that changes the likelihood of a future [[behaviour]].

The terms negative and positive feedback can be used loosely or colloquially to describe or imply [[criticism]] and [[praise]], respectively. This may lead to confusion with the more technically accurate terms positive and negative reinforcement, which refer to something that changes the likelihood of a future [[behaviour]].

Negative feedback was applied by [http://en.wikipedia.org/wiki/Harold_Stephen_Black Harold Stephen Black] to electrical amplifiers in 1927, but he could not get his idea patented until 1937.[2] [http://en.wikipedia.org/wiki/Arturo_Rosenblueth Arturo Rosenblueth], a Mexican researcher and physician, co-authored a seminal 1943 paper ''Behavior, Purpose and Teleology''[3] that, according to Norbert Wiener (another co-author of the paper), set the basis for the new science cybernetics. Rosenblueth proposed that behaviour controlled by negative feedback, whether in [[animal]],  or [[machine]], was a determinative, directive principle in [[nature]] and human [[creations]].[citation needed]. This kind of feedback is studied in cybernetics and control theory.[http://en.wikipedia.org/wiki/Feedback]

Negative feedback was applied by [https://en.wikipedia.org/wiki/Harold_Stephen_Black Harold Stephen Black] to electrical amplifiers in 1927, but he could not get his idea patented until 1937.[2] [https://en.wikipedia.org/wiki/Arturo_Rosenblueth Arturo Rosenblueth], a Mexican researcher and physician, co-authored a seminal 1943 paper ''Behavior, Purpose and Teleology''[3] that, according to Norbert Wiener (another co-author of the paper), set the basis for the new science cybernetics. Rosenblueth proposed that behaviour controlled by negative feedback, whether in [[animal]],  or [[machine]], was a determinative, directive principle in [[nature]] and human [[creations]].[citation needed]. This kind of feedback is studied in cybernetics and control theory.[https://en.wikipedia.org/wiki/Feedback]

==References==

==References==

# Peter M. Senge (1990). The Fifth Discipline: The Art and Practice of the Learning Organization. New York: Doubleday. pp. 424. ISBN 0-385-260-946.

# Peter M. Senge (1990). The Fifth Discipline: The Art and Practice of the Learning Organization. New York: Doubleday. pp. 424. ISBN 0-385-260-946.