Reinforcing feedback loops, or positive feedback loops, occur when an initial change is reinvested to further that change in the future. The bigger the initial push, the bigger the consequential push. Reinforcing loops get things moving. They build momentum. When change is agile or growth persists, reinforcing loops are often at play.
When you add money to your bank account it earns interest based on the amount in the account. The interest is reinvested to the money in the bank account so they amount of interest will be greater in the future.
When consumers adopt a hot new product, more potential consumers encounter the product and are likely to purchase it themselves strengthening the word of mouth advertisement and leading to more adopters in the future.
When immigrants settle in a particular part of a foreign land, they build infrastructure and provide services, creating an environment that in turn attracts more people like them. This leads to the formation of large homogenous ethnic neighborhoods like China town in San Francisco.
Growth usually can’t continue forever, so where there is a reinforcing loop, there is typically a balancing feedback loop to stabilize the system, but it might not be as strong as the reinforcing loop or might not yet be activated.
Additional Examples:
- Interest payments due on a Credit Card account will increase exponentially if the card owner doesn’t pay off debt.
- High performing students sometimes receive special attention from teachers and are told that they are smart, which boosts their confidence and helps them perform better, like a self-fulfilling prophecy.
- When one company cuts its prices, the competitor loses customers, and is forced to cut prices too. The two companies may then be involved in a downward spiral of price cuts that hurts both until both can agree to stop.
- The greater the population, the more children will be born. When those children grow up to be adults, they will have children too. Rapid population growth can lead to great consequences on our natural resources and climate.
- When a company’s product is successful, people will talk about it and through word of mouth, the product will become even more successful.
- The rich get richer; poor get poorer
++
Additional Learning:
Systems & Us 
you put they twice in China town example. Thank you for this website!! very helpful. Struggling Systems Dynamics Student
Yes I am also a Struggling Systems Dynamics Student determined to become profecient. Thank you for the additional source.
The greater the population, the more children will be born. When those children grow up to be adults, they will have children too. Rapid population growth can lead to great consequences on our natural resources and climate.
This one rubbed me wrong. I understand the example, but there is an underlying “solution” of depopulation attempts. At the risk of running too far with this, maybe take out the depopulation example?