1. PSY402 Theories of Learning Monday January 13, 2003

2. Experimental Evidence  Rats drink little saccharin water at first but increase over time.  Loud tones (110 db) produce different responses depending on the background noise (60 vs 80 db). Habituation occurred at 60 db Sensitization occurred at 80 db A loud background is arousing, leading to greater reactivity, not less.

3. Conditions Producing Change  More intense (stronger) stimuli produce stronger sensitization, less likely to produce habituation.  Greater sensitization and habituation occur when the stimulus is repeated frequently.  Changes in the stimulus prevent habituation. Turkeys respond to shape changes.

4. Conditions (Cont.)  Sensitization can occur to many kinds of stimuli but habituation occurs only with innate responses.  Habituation and sensitization are transient (go away after seconds or minutes between stimuli). Except long-term habituation.  Dishabituation – response returns when a sensitizing stimulus occurs.

5. Opponent-Process Theory  An explanation for addictions.  All experiences produce an affective reaction (pleasant or unpleasant) – A state.  This reaction gives rise to its opposite – B state. B state is less intense and lasts longer.  Over time, the A state diminishes and the B state increases.

6. The Addiction Process  Tolerance – diminished A state.  Withdrawal – increased B state.  Addictive behavior is a coping response to the change in B state. People try to enhance A state to offset the unpleasantness of the B state. Without withdrawal symptoms there is no addictive behavior. Time prevents B state strengthening.

7. What Sustains Addiction?  The B state is a non-specific aversive feeling. Anything similarly aversive will motivate the addictive behavior, even if it has no relation to the substance. Daily life stress produces a B state that results in behavior to create an A state.  Parachute jumpers – create a B state in order to feel the A state.

8. Acquisition of a Conditioned Response Chapter 3, pages 37-46

9. Acquisition, Extinction, and Spontaneous Recovery

10. Conditioned Emotional Responses  Fear is an anticipatory pain response based on past experience.  Fear is conditioned whenever a CS is associated with an aversive (painful or negative) event.  Fear motivates two responses: Escape (when pain is present) Avoidance (when pain is imminent)

11. Examples of Conditioning  Popcorn at the movies.  Fear of flying -- stronger with more turbulence (a stronger UCS).  An antelope shying away from low tree branches.  Nausea at the smell of alcohol after a hangover.

12. Conditioning Situations  Sign-tracking (autoshaping) – animals must recognize signs of food (UCS) and respond (UCR). Pigeons pecking at key. UCR, not an operant response, because behavior is specific to the stimulus.  Eyeblink conditioning UCR is rapid, CR is slow. Many trials are needed (100 pairings)

13. Fear conditioning  Avoidance is not a good measure of fear.  Suppression of an operant behavior occurs with a feared stimulus. First – an operant behavior is learned. Second – a CS is paired with an aversive UCS. Third – the CS is presented in the operant chamber.

14. Suppression Ratio D uring CS SuppressionRatio = D uring CS + Without CS  The amount of time during and without the CS is equal.  The more fear, the lower the suppression ratio. Ratios typically fall between 0 and.5

15. Flavor Aversion Learning  Garcia – rats will not drink water with saccharin if they get ill after drinking. Significant avoidance occurs after just one trial.  Human food aversions are related to illness (89%). Even if illness occurs hours later it is linked to the previous meal. Not cognitive – know food not to blame