PSY 301 1st Edition Lecture 18 Outline of Last Lecture I. Positive PsychologyII. Cognitive TheoriesIII. Key cognitive ConceptsOutline of Current Lecture I. LearningII. Classical ConditioningIII. Biological Bases of LearningIV. The Unconditioned PairV. Garcia StudyCurrent LectureLearning: a relatively long lasting change in thought or behavior produced by environmental events1. refers to actual changes in the person2. performance: new behaviors produced by these changesTwo types of conditioning:• 1. classical conditioning: learning new connections between stimuli• 2. operant conditioning: learning new connections between acts and their consequences• Learning to associate one stimulus with another.• Learning to associate a response with a consequence.• Assumes that basic laws of learning exist.1. complex learning involves combinations of these simpler laws2. allows for study of animals and simple situationsClassical Conditioning • Classical Conditioning: the processes involved when an organism learns to associate two events• First discovered by Ivan Pavlov in studying salivation in dogs.• Before conditioning:• Food is presented (unconditioned stimulus, US)• The dog salivates to food (unconditioned response, UR)• A tone is sounded (neutral stimulus)• Dog does not salivate (no response)• During Conditioning:• The tone is sounded• Food is presented• Dog salivates to food • (experimental trial: tone, food, salivation)• After conditioning: after many trials, the tone and the food becomes associated and the dog will salivate to the tone alone• Tone is presented (conditioned stimulus, CS)• Dog salivates (conditioned response, CR)Biological Bases of LearningLearning depends upon neural plasticity: the capacity for neurons to change the way in which they function in response to experiencePlasticity always involves changes at the synapse (changes on the ways in which neurons communicate with each other). Learning involves one of three kinds of changes at the synapse:1. presynaptic facilitation: after learning some neurons send out a stronger stimulus2. long-term potentiation (LTP): after learning some neurons become more sensitive to the signals they have been receiving all along3. new synapses: after learning, some neurons form entirely new connection with other neuronsThe unconditioned (unlearned) pairUnconditioned stimulus (UC): a stimulus which innately produces the unconditioned responseUnconditioned response (UR): a response the innately occurs to the UCSConditioned stimulus (CS): a stimulus which is initially neutral (it never naturally produces the conditioned response), but which comes to produce the conditioned response after being associated with the USConditioned response (CR): a response that is made naturally to the UCS, by never to the CS; thelearned response to the CS• Explanation• 1. food naturally causes the dog to salivate • 2. the bell becomes associated with the food• 3. the dog learns that the bell predicts the coming of food• 4. the dog salivates to the bellThe CS serves as a signal that the UCS is coming1. the CS can be used to predict the coming of the US2. when the CS doesn’t occur it predicts the absence of the US• a. when the UCS is aversive, the absence of the CS can serve as a safety signal3. these contingencies don’t have to be perfect to produce conditioning, but the occurrence of the UCS must be more probable after the CS Some contingencies are hard to learn1. overshadowing: a very dominant component of a complex stimulus will be so strong that it becomes the only CS2. blocking: difficult to attach a new CS to a well- established CS-UCS relationship• Acquisition is the initial learning, in which an association is formed between a neutral stimulus and an unconditioned stimulus1. more pairings of the CS and the US produce a stronger CRa. these pairings reinforce the UC-CS relationship b. called reinforced trialsExtinction: if the CS is repeatedly presented without the UC, the CR will eventually be eliminated1. a CR can easily be reconditioned by reintroducing the US2. an extinguished CR can be spontaneously recoveredStimulus generalization: the CR will be made to stimuli that are similar to the CS1. CR is weaker than to the CS2. The more similar the CS and the new stimulus, the stronger the CR3. generalization is progressiveStimulus discrimination: making the CR to the CS and not to a similar unreinforced stimulusHigher-order conditioning: using a well-established US-CS relationship to produce new conditioning1. The previous US becomes the CS in the new conditioningBiological constraints on learning1. different kinds of animals are biologically prepared to learn differentkinds of associations with different degrees of difficulty2. taste aversions: an animals learns to avoid food with a certain taste because it is associated with bad experiencesGarcia study:Part 11. Thirsty rat licks a water tube and 2 things happen: receives sugar water and turns on a light/tone combination2. After drinking, all rats have an aversive experience1. A. half the rats get violently sick2. B. half the rats are shocked through their feetPart 21. Rats are water deprived again2. Allowed to drink in one of 2 situations:A. half drink sugar water, but without a l light/tone soundB. half drink plain water, but with the light/tone soundWhich rats will drink?Rats who were made ill:1. will NOT drink sugar water, without light/tone2. WILL drink plain water, with light/toneRats who were shocked:1. WILL drink sugar water, without light/tone2. will NOT drink plain water. With
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