Causal Loops Stock and Flow Spring 2016
Q126. Why do people scream into cell phones? Answer in terms of feedback. Land Line Cellular I talk I talk - + - x I hear I hear
Causal Loops • What can be bigger or smaller? • How do these relate to one another? • How do the loops behave?
Heating a House • What can be bigger or smaller? • Room temperature Heat • Heat coming into room - + B alancing • How do these relate to one another? Temperature • More heat … higher temperature • Higher temperature … less heat • How do the loops behave?
Q112 Sketch a causal loop diagram: Being sad… …makes you frown… …which makes people avoid you… …which makes you lonely… …which makes you sad…
Q113 Sketch a causal loop diagram for this system (be sure to label each link and the overall loop). Comment on the long term equilibrium of this system. Being happy… 1. …makes you to smile… 2. …makes people approach you… 3. …makes you feel social… 4. …makes you happy…
Sheep • What can be bigger or smaller? • How do these relate to one another? • How do the loops behave?
Sheep • What can be bigger or smaller? • number of sheep • number of lambs • number of dead sheep • How do these relate to one another? • more sheep … more lambs • more sheep … more dead sheep • more lambs … more sheep • more dead sheep … fewer sheep • How do the loops behave?
Sheep
Sheep “valves”
Sheep + + Fertility DeathRate
Other Examples
Sheep and Wolves • Sheep have lambs at rate B s per time period • Wolves have wolflets at rate B w per time period • Sheep die when eaten by wolves • A wolf eats P sheep per time period • Wolves die from old age at rate Dw per time period • Draw causal loops
Lambs + + R Sheep s + - e B v l o W Wolves Sheep + R + Wolflets
Innovation
Moore's tech adoption cycle
Moore's tech adoption cycle
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