Jan 17 2012
Reflection Post-feedback loops
I am still a little confused about feedback loops. I know that you shouldn’t associate positive with good and negative with bad and I understand the different things that cause the feedback loops. For example, jobs and sanitation lead to positive feedback loops and crime and pollution lead to negative feed back loops. So does that mean that in a positive feedback loop those good things are brought to the city causing more people to move in? And that then the city is accelerating too quickly which can be a bad thing? And in a negative feedback loop those bad things take place in the city which causes people to move out but it could be a good thing because then it is able to self correct itself? This is kind of confusing but I just want to make sure that I am understanding this right so if some one could clarify that would be great.
I think the main different to associate with the two is that positive feedback loops are self-accelerating, meaning that there aren’t any breaks, and the negative feedback loop is self-correcting, meaning that there are breaks. So for the positive loop, things attract people to the city (jobs, museums, schools, sanitation, etc.) but since these factors attract most people, the city keeps growing as people want to move in. As a result of the attractiveness of the city, it becomes less desirable due to crime, pollution, traffic, etc. So these negative things cause people to flee the city, correcting the huge influx of people – negative feedback loop. So positive doesn’t mean good, it just means that people are coming into the city and negative means that the factors cause people to leave the city.
(negative loops also add to the problem with urban sprawl I think, but that’s a different topic.)
Hope that helps/is all correct, correct me if I’m not.
Good Danae. Positive or negative has to do with what happens to the feedback-if the output feeds back in as input, you get a positive feedback loop that self-accelerates. If the output slows or halts the system (puts on the brakes), then it is a negative feedback loop.
Now, as for urban sprawl your book explained another positive feedback loop that is influenced by gas taxes in the USA (accelerates urban sprawl). That one is not a negative loop.