1. Principles of Feedback Control
Mafuyu Kitahara
English Theme8
Summary of Chapter 2, Carver & Scheier (1998), On the Self-Regulation of Behavior, Cambridge Univ. Press.

2. Feedback control Goal of Chapter 2 To show abstract princples
Examples from domains other than psychology
Feedback process
Control of regulation of values within a system
Cybernetics: coined by Wiener (1948)
Background
First computer in history: ENIAC (1946)
Information science: bit, entropy, noise
Systems without internal control: e.g., clock, camera

3. Negative feedback (1) Concept
4 elements: input, reference, comparator, output

4. Negative feedback (2) Example: thermostat Effect on evironment?
Output has indirect connection with input

5. Additional issues (1) Sloppy vs. Tight control Lag Time
how precisely the comparator works
Thermostat: 0.01, 0.1, or 1 degree deviation?
Lag Time
Output function cannot work immediately
Thermostat:
Slow heater (steam) vs. Quick heater (gas)

6. Additional issues (2) Intermittent feedback Discontinuous: Continuous:
Output side: heater is only ON or OFF
Input side: sensor works occasionally
Continuous:
Automatic steering system in a ship

7. Further constructs (1) Positive feedback loops Thermostat example:
set goal as more than 20C (needs upper limit)

8. Further constructs (2) Open loop systems
No checking on the consequences
e.g. Spark plugs in a car engine
Order: prespecified
Timing: depends on the speed
Useful for high-speed control
Precise, No lag time, No intermittency
Not useful for psychology

9. Feedforward Anticipatory output First cycle Best estimate
No input is available

10. Interdependency Interaction between feedback loops
Not explicitly connected but disturbing each other

11. Reference value and input function
Slow adjustment of reference value
e.g.
Sleep hours

12. Hierarchies Superordinate and subordinate systems
e.g., person and thermostat