Regulatory Systems.doc

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 Diversive e