Conditioning Learning Exam 2 Rescorla Wagner 1972 V associative strength Alpha CS salience Beta US salience Lambda perfect learning or asymptote Vtot sum of associative strength Practice effects salience intensity and asymptote we don t learn something forever should be addressed in ANY model Rescorla Wagner model assumes that learning increases until you understand what you re trying to learn Discrepancy Resolution Model Initially there s a big discrepancy between what you know and what you need to know as you learn more there is less of a discrepancy When you re surprised from the outcome of a conditioning trial you learn When you re not surprised you don t learn Positive increment in associative strength when you get more than you expect negative increment in associative strenth when you get less than you expect Strong association ex Tone Shock means you figured it out Learning is a limited resource project Stimuli compete for attention the stimulus that wins is the stimulus that you learn about Experiment Acquisition of associative strength 16 trials Trials 1 8 tone shock acquisition of associative strength Acquisition curve Animal wants to know everything he can Begins at 0 large discrepancy Learns a lot on 1st trial because he was very surprised by the Lower increase in CR is less in sequential trials because there is less to know less discrepancy to resolve and he is less surprised W each trial the discrepancy of what he knows and would like to outcome of the event in the 1st trial know becomes less and less Trials 9 16 tone alone extinction Extinction curve Beginning trial 9 exhibits fear because of what he has learned Decrease in CR during 10th trial because he is surprised not to get Continues until animal learns the shock won t come shocked What would Rescorla Wagner say about this Calculating the change in associative strength 1 to 1 Associative strength of 0 means the animal knows nothing associative strength of 1 means the animal has perfect excitation and associative strength of 1 means the animal has perfect inhibition If the salience of a stimulus is 0 it cannot be detected perfect stimulus has salience 1 If the stimulus is perfect then the animal will learn it all on trial 1 Equation for example Assume alpha 0 5 and beta 1 0 Trial 1 V 0 5 1 0 1 0 0 5 Trial 2 V 0 5 1 0 1 0 5 0 25 Trial 3 V 0 5 1 0 1 0 75 0 125 Trial 4 V 0 5 1 0 1 0 875 0 063 Trial 9 V 0 5 1 0 0 1 0 5 Trial 10 V 0 5 1 0 0 0 5 0 25 Trial 11 V 0 5 1 0 0 0 25 0 125 In reality extinction is much slower than depicted because the animal is reluctant to give up the association learned in acquisition Reaquisition Experiments Animals maintain old memories so they can use them when important sometimes tone means shock sometimes no choose which memory in time of need important psychologically Animal has one memory after acquisition and gains another after extinction animal has 2 memories at time of reaquisition Rescorla Wagner Model 72 stimuli that go together have higher salience ex grape flavor poison 1 1 V 1 1 1 0 1 complete learning on 1st trial Blocking always get sick from rice expect to get sick from rice regardless if it s from anything else that you eat Blocking No Blocking 1 L S 0 5 0 2 L S 0 75 0 3 L S 0 875 0 4 L S 0 94 0 5 LT S LT S Animal shouldn t learn much about the tone if the light predicts the shock Learned about 0 03 about the tone Overshadowing never had rice or fish and get sick blame it on the fish b c fish is more salient If you have fish sausage equally salient there s uncertainty in which caused the illness No Overshadowing Overshadowing 1 L 0 5 LT 1 L 0 75 LT 1 L 0 875 LT L 0 5 in each trial after T 0 5 in each trial after overshadowing effect Light competes for associative strength w tone F fish S sausage FS sick FS sick don t know which causes sickess 50 50 chance of either one FS sick F sick say fish makes you sick not the sausage Conditioned Inhibition I m in a bad neighborhood at night and am scared until a police officer walks behind me and inhibits my fear 1 L 2 L 3 L 4 L 5 LT 6 L 7 L 8 L 9 LT 10 L 11 L 12 L 13 LT The tone is acquiring negative associative strength b c it predicts less than the animal expected Light becomes a very good exciter and tone becomes a very good inhibitor Tone has a very negative associative strength Why does it take so long for a conditioned inhibitor to become an exciter ex hard to accept if police started to rob people Rescorla Wagner Model does not predict facilitated reacqisition Latent inhibition If I eat oysters 1000x w o getting sick and then one day I get sick I won t blame the oysters Latent Inhibition No Latent Inhibition 1 L 1 2 L 2 3 L 3 100 L 100 101 L no fear 101 L CR Rescorla Wagner Model says latent inhibition should not occur Side note Any good theory can t only explain available data but must also make novel predictions The Rescorla Wagner Model predicted many things that turned out to be true but also had some failures Experiment of success of R W model T tone S Shock L Light C Click T S T S T S T S TL T S T S T S T S TL CL S Light becomes an inhibitor of fear Click becomes an exciter but since it is in presence of the light an inhibitor the animal is super surprised and the click produces a huge CR Failures model doesn t predict latent inhibition or facilitated reacquisition Why does the conditioned response look the way it does Ex Pavlov US substitution transfer surrogate like a dance Tone CS Food US Salivation UR Salivation CR Why did all of the dogs salivate Why do none of them do something else Pavlov thinks that the tone becomes a surrogate stimulus for the food so the tone now causes the same reflex as the food would reflex transfer properties of US are transferred to the CS Pavlov did saw Where the CR mimics the UR makes it easier for the animal to prepare for the US Conditioned salivation Conditioned leg flexion Eyeblink conditioning Taste aversion Autoshaping not seen by Pavlov but CR mimics the UR Reflex transfer doesn t explain the form of the CR opposite of the UR Fear conditioning Heart rate conditioning Drug conditioning for protection Why does the stimulus that predicts heroin make your heart rate increase Fear conditioning CR freezing after tone comes on Heart rate conditioning …