PSY402 Theories of Learning Wednesday March 5, 2003
Expectancies Expectancy –mental representation of event contingencies. Dickinson – an expectancy contains two kinds of information: Associative link between two events – classically conditioned, mechanistic. Behavior-reinforcer belief – consequences of action, operant, intentional.
Testing Associative Links Two groups trained to bar press: One group reinforced with sodium (Na) Other group reinforced with potassium (K) Both tested when deprived of sodium. Irrelevant incentive effect – sodium deprivation activated associative link for Na rats but not K rats. Could be due to beliefs not links.
Testing for Beliefs Reinforcer devaluation effect – what happens if reinforcer is diminished in value after training? One group got sucrose for bar-pressing and food regardless of behavior. Other group got food for bar-pressing and sucrose non-contingently. Sucrose devalued during testing. Bar pressing was lower when the sucrose was behavior-contingent.
Importance of Disgust Devaluation is a two-stage process: A disgust reaction is associated with the reinforcer (devalued by illness). The reinforcer must be reexperienced. Devaluation of the reinforcer occurs when reexperience activates the associated disgust. Studied using ondansetron – a strong anti-emetic (reduces nausea).
Importance of Habits Dickinson acknowledged that habits do exist and can control behavior. Expectancies (behavior-reinforcer beliefs) control actions before habits are established. Behavioral autonomy – control of responding by habit rather than expectancy. Habit responds to devalued reinforcer.
Learned Helplessness Theory Seligman – depression is learned. Depression occurs when people believe: Failures are due to uncontrollable events. Failure will continue as long as events are beyond their control. Depression arises from helplessness.
Animal Research Step 1 -- three groups of dogs: Inescapable shock – no control. Escapable shock -- terminated if the dog pressed a panel. No shock Step 2 – 10 trials of signaled avoidance training in shuttle box. 2/3 of inescapable shock dogs did not learn to jump during step 2.
Helplessness in Humans Hiroto – three groups of college students: Uncontrollable group – wrongly told that pushing button would end noise. Escapable group – pushing button ended noise. Control – no noise. Tested using finger shuttle box. Uncontrollable group did not escape
Characteristics of Helplessness Motivational impairment – unable to initiate voluntary behavior. Mice in water maze. Nonspecific – carries over to a variety tasks and test situations. Intellectual impairment – incapable of benefiting from future experience – even if they jump, don’t learn. Emotional trauma – neg. affect.
Studies of Depressives Show similar results to learned helplessness studies. Depressed individuals do not escape noise, responding like inescapable non-depressed individuals. Depressed individuals do not adjust likelihood of succeeding upward when they experience success. They credit chance not skill.
Criticisms of Seligman’s Theory There is more to depression than learned helplessness. Helplessness subjects described the task as a skill task, even though acting as if it were a chance task. Failure to replicate performance deficits in humans – facilitation of performance instead. May be due to attributions.
Attribution Theory Causal attributions of failure have three dimensions: Internal-external – internal traits or characteristics vs environmental forces Stable-unstable – past causes will persist vs new forces will determine future outcomes Global-specific – outcome relates only to one task vs outcome effects everything.
Two Kinds of Helplessness Personal helplessness – an individual’s inability causes failure. Universal helplessness – the environment is structured so that no one can control future events. Abramson -- both kinds lead to depression. Vary on external-internal dimension. Low self-esteem only with personal.