PSYC 3F40 Lecture Notes - Playtime, Thermostat, Reinforcement
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Regulatory Systems
Regulatory behaviours: tends to bring physiological conditions back to normal,
thus restoring the condition of homeostasis
Homeostasis: process which physiological characteristic (body temperature, blood
pressure) are regulated so that they remain at their optimum level
4 features of System
1. System variable: variable controlled by regulatory mechanism (temperature in
a room)
2. Set point: optimum value for system variable (22.5 degrees C)
3. Detector: Mechanism that signals when system variable deviates from set point
(thermostat)
4. Correctional mechanism: capable of restoring the system variable to set
point(heater turns on when temp goes below 22.5, or off when it goes above)
Negative Feedback: a process whereby the effect produced by an action serves
to diminish or terminate that action. Regulatory systems are characterized by
negative feedback loop.
Drive Reduction Hypothesis:
•the hypothesis that a drive produces an unpleasant state that causes an
organism to engage in motivated behaviours (hunger is a drive that produces
an unpleasant state caused by going without food for a long time, cause one
to engage in behaviours that will lead to food)
•reduction of drive is assumed to be reinforcing (Eating is a drive reducing act,
and is reinforcing)
•biological needs, caused by deprivation of necessities of life are unpleasant
•hypothesis is disfavoured b/c drive is impossible to measure, and b/c events
we experience as reinforcing are also exciting or drive increasing
•in general: the experiences we really want to repeat are those that increase
our level of arousal
Physiology of Reinforcement
•neural circuits stimulated by electricity are also responsible for the
motivating effects of natural reinforcers such as food, water, or sexual
contact, and drugs such as cocaine or alcohol.
•Essential component of reinforcement system is neurons that release
dopamine as their transmitter substance
Optimum level theory
Optimum level hypothesis: organisms will perform behaviour that restores the
level of arousal to an optimum level
•Attempt to explain positive and negative reinforcement
•When arousal is too high, less stimulation is reinforcing and vice versa