The examples are how not to use the word.
"feedback" is a noun, not a verb, which would be two words, though I can't think of an uncontrived example where such an expression would be used.
Again, this is totally inappropriate use of the word.
Feedback is the technical name of a control method, originally in electronics and acoustics, but now used (with the same meaning) in other fields.
OED defines the word as:
- information about reactions to a product, a person's performance of a task, etc. which is used as a basis for improvement.
"throughout this process we have obtained valuable feedback"
- a screeching or humming sound resulting from the return of a fraction of the output signal from an amplifier, microphone, or other device to the input of the same device.
Feedback uses the output of some process to adjust the operation of that process, and is usually characterized in two ways:
- Negative feedback causes the process to reduce what it's doing.
- A thermostat notices that the room is now hot enough, so tells the heater to not produce so much heat.
- A thermostat notices that the room is now cool enough, so tells the air-conditioner to not produce so much cold air.
- Your body notices that your blood sugar has risen, so it suppresses your appetite.
- You notice your car is getting close to the shoulder of the road, so you steer slightly away from it.
- You work hard and get hot, so you sweat to cool yourself.
- The wind is cold, so you shiver to generate heat to warm yourself.
- Positive feedback causes the process to increase doing what it's doing.
- The heat from a BBQ-lighter causes dry wood to release flammable gasses that burn, creating a larger flame, which releases even more gasses, which … .
- Water leaks through a crack in a dam, which erodes the crack and makes it larger, which allows more water to flow, which erodes the crack even more, which … .
- Sound from a speaker reaches the microphone, which sends it to the amplifier, which sends a louder sound to the speaker, which goes to the microphone, and to the amplifier, and even louder to the speaker, and … .
- Uranium naturally decays over billions of years, each atom randomly and spontaneously splitting into two smaller atoms, a few neutrons, and a bit of energy.
When a free neutron collides with a uranium atom, it can trigger it to split.
If the uranium ore is more concentrated, the neutrons released by natural decay are more likely to hit other uranium atoms and cause them to split too, speeding up the decay.
If a substantial amount of uranium is highly concentrated, this will cause a chain reaction of continually splitting atoms, producing heat energy, which can be used to generate electricity in a power station.
But if it is even more concentrated, each split can trigger two other splits, and they can trigger two more, and so on until the entire mass is destroyed in a fraction of a second.
The resulting massive explosion is how an "atom bomb" works, positive feedback at its most extreme.
Notice that negative feedback tends to be desirable for ensuring long-term stability, while positive feedback tends to be destructive and sudden.
For instance, while walking through a narrow valley, if one strays too far to the right or left, the land slopes up and effectively pushes one back to the middle of the valley.
But if one walks along a narrow ridge between two valleys, if one strays to far to the right or left, the land slopes down and effectively pushes one even further away from the middle of the ridge, where the land gets even steeper and one is pushed even more and eventually falls into the valley.
Whenever disturbed, a marble will return to the bottom of a rounded bowl (negative feedback provides stability), but if balanced on top of an upside-down bowl, the slightest thing will cause it to roll off (positive feedback causes instability).
The expression has since spread to commercial and social environments, where it originally was used correctly (e.g. comments about how one's behaviour had a bad effect will inspire one to improve that behaviour (negative feedback), while comments about how one's behaviour had a good effect will further encourage that behaviour (positive feedback).
[Politically Incorrect Aside]
The politically correct types have abused this, presenting negative feedback as an inherently bad thing (no one likes to be criticised), and positive feedback as an inherently good thing (boost everyone's self-esteem).
The results are of course very damaging for everyone (but make sure you don't mention that to anyone).
[/Politically Incorrect Aside]