← Thinking in Loops · Lesson 2 of 4
Loops that snowball or settle
A loop is a stock that changes its own flow. Some loops feed themselves: the more there is, the faster it grows. Interest on savings works this way, and so does a rumour, or weeds in a garden. These loops snowball.
Other loops push back. A thermostat turns the heat down as the room gets warmer, so the room heads toward a set temperature and stays near it. Hunger and eating work the same way. These loops settle.
Most real things have both kinds pulling at once. A town grows because people bring jobs, and slows because homes fill up. Which loop is winning tells you more than any single number does.
Snowball and settle
Snowballs: starts at 10, ends at 159, highest 159. Settles: starts at 10, ends at 96, highest 96.
Try this: Raise the rate. The snowball line runs away; the settle line just gets there sooner.
What this model assumes
- Savings that earn interest grow by a share of themselves (a snowballing loop). (well established)
- A thermostat closes a share of the gap each step (a settling loop). (well established)
- Nothing outside the loop interferes. (a guess)
A new café gets busier the more people see a queue outside, until the queue gets so long that people walk past. Which describes it?