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March 3 2014 Rescorla and Wagner 1972 V associative strength change CS Salience 0 to 1 US Salience 0 to 1 Perfect learning or asymptote always going to be 1 Could be cases that it s 0 V Sum of associative strength How much you already know What you already learned Rescorla model will attempt to address all them blocking overshadowing contingency cue to consequences latent Inhibition we get better with practice salience intense stimuli are learned better than weak stimuli and asymptote is the point when we stop learning March 5 2014 Cue to consequence Certain stimuli are easy to learn such as food poison it is a strong conditioning Instead of Light and shock let s use grape and poison In 1 trial asymptote is reached Grape CS salience is 1 salience of US poison is also 1 Change of associative strength is equal to 1 Blocking versus no blocking Blocking o Trial 1 Light shock 5 o Trial 2 Light shock 75 o Trial 3 Light shock 875 o Trial 4 Light shock 94 o Trial 5 Light tone and shock These are all sum of associative change No blocking o First four trials no stimuli o Trial 5 Light tone and shock CS light Salience is 5 US shock Salience is 1 Change in associative change for light is 5 so the change in associate change in tone 5 for no blocking Trial 6 of Blocking will show no additional learning occurs perfect learning has been achieved Intensity Overshadowing No overshadowing Trial 1 Light shock 5 Trial 2 Light shock 75 Trial 3 Light shock 875 Trial 4 Light shock 94 CS salience is 5 US salience is 1 Overshadowing Trial 1 Light tone shock 5 Trial 2 Light tone shock 5 Trial 3 Light tone shock 5 Change in associative strength for light 5 1 1 0 5 same for tone Sum of associative strength is then equal to 1 0 Next trials no new learning you don t know whether it s the light or tone causing the shock 50 50 However when you just get light then shock well you will say Aha It s the light that shocked me and then ignore tone you will think back aka retrospective thinking But the associative strength still remains at 5 which makes no sense at all There should be a much higher associative strength right Conditioned inhibition Example the police inhibit your fear of thugs in a bad neighborhood First 4 trials you get light shock Associative strength of that learning will gradually increase you will pair light shock pretty easily Then you get light tone no shock your associative strength will decrease and tone will be considered a negative associative strength get less than expected Then continues light shock increases in associative strength and then decrease again when light tone no shock Each time tone decreases in associative strength Rescorla Wagner predict all of this also predicts retardation If tone becomes a excitatory it will take many trials and summation positive value light plus negative value tone very low associative strength Latent inhibition Light followed by nothing 100x Then on the 101st trial light followed by shock o There will still be no fear of the light March 10 2014 Perkins 1967 Preparatory Response Hypothesis Conditioned Responses Mimic o Fear Conditioning Tone as CS Tone comes on US shock comes on the whole body What does the shock usually illicit Agitation o Heart Rate Conditioning o Drug Conditioning o Conditioned Salivation o Conditioned Leg Flexion o Eyeblink Conditioning o Taste Aversion Mirror Pavlov US substitution Transfer Surrogate Tone CS Food US UR salivation CR salivation March 24 2014 Schedules of Reinforcement Fixed ratio schedule Cumulative Record FR 5 Animal is compelled to work as fast as they can for food because if they don t work fast they don t get as much food assuming that they are not getting too much food FR 100 Animal must respond 100 times to get a single piece of food PRP post reinforcement pause The more you require from the animals the longer the pause will be in between Variable Ratio Cumulative Record FR 5 VR 10 Fixed Interval FI Ten responses for one piece of food Rate of responding for both FR schedule and VR schedule will be the same The difference is that the animals don t usually take a break in VR schedule no PRP On the VR schedule the pause may occur randomly The amount of time that must expire between successive reinforcements o Example paycheck every two weeks o You have to wait two weeks but then you only have to go once to pick up check Animals estimate the passage of time Variable Interval VI No long extended pause because if you wait too long you miss the opportunity for food Missing two seconds may cost you 20 of the food

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Rutgers PSYCHOLOGY 311 - Rescorla and Wagner

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