The Rescorla-Wagner Model Associative model of conditioning You are not responsible for the math model (4.1) Concept of surprise in a mathematical model Surprise increases associative strength This is the typical learning curve With repeated experience surprise goes down With repeated experience growth of associative strength slows down see Figure 4.17

This figure will not be covered on the exam The Principles of Learning and Behavior, 7e by Michael Domjan Copyright © 2015 Wadsworth Publishing, a division of Cengage Learning. All rights reserved.

Evaluation of the Rescorla-Wagner Model Effective in explaining the blocking effect Able to predict Overexpectation of a US effect Not adequate to explain negative conditioning

The Blocking Effect Kamin (1968) demonstrates that just temporal contiguity is not sufficient for learning Procedure see Figure 4.15 Phase 1: Pair CSa (tone) with US (footshock) Phase 2: Pair CSa (tone) and CSb (light) with US (footshock) Phase 3: Test CSa (tone) only and CSb (light) only Conditioning to tone is strong, but conditioning to light is weak Tone blocked the acquisition of an association between light and the footshock Kamin – US has to be surprising to be effective – the US was not surprising because it was well predicted by the tone Interesting example using geometric cues see figure 4.16

tone shock tone + light Figure 4.15 – Diagram of the blocking procedure. The Principles of Learning and Behavior, 7e by Michael Domjan Copyright © 2015 Wadsworth Publishing, a division of Cengage Learning. All rights reserved.

FIGURE 4.16 Blocking in human learning about geometric cues. Human participants had to move a cursor to the correct geometric location (indicated by + in each triangle) on conditioning trials in Phase 1 (for the blocking group) and Phase 2 (for all groups). Percent correct during the test trials is indicated in the third column (based on Prados, 2011). The Principles of Learning and Behavior, 7e by Michael Domjan Copyright © 2015 Wadsworth Publishing, a division of Cengage Learning. All rights reserved.

Evaluation of the Rescorla-Wagner Model Novel Prediction: Overexpectation of a US Overexpectation of a US results in the loss of associative value despite pairings with US Phase 1:    CSa -> US, and CSb -> US Each independently perfectly predicts the US Phase 2:    CSa + CSb -> US Summation of associative strength is greater than the US can support Both CSa and CSb will loose associative strength until the sum of their associative strengths is equal See Figure 4.18

Figure 4.18 – Diagram of the overexpectation experiment The Principles of Learning and Behavior, 7e by Michael Domjan Copyright © 2015 Wadsworth Publishing, a division of Cengage Learning. All rights reserved.

Evaluation of the Rescorla-Wagner Model Conditioned Inhibition: see figure 4.19 CS+ --- US; and CS+/CS- --- no US Initial overexpectation of the US on CS+/CS- trials Associative value of CS+/CS- must sum to zero to accurately predict the absence of the US This can be accomplished by making the associative value of the CS- negative. Extinction of conditioned inhibition does not occur as predicted Because extinction is not simply the reverse of acquisition Can not produce negative associative conditioning

The Principles of Learning and Behavior, 7e by Michael Domjan Copyright © 2015 Wadsworth Publishing, a division of Cengage Learning. All rights reserved.

Attentional Models of Conditioning Pearce-Hall (1980) CS-processing model Pay attention to a CS that could become predictors of US Pay attention to the CS when US is surprising With experience the CS is a good predictor of US If the US was predicted, then attention to the CS declines If the US was not predicted, then attention to the CS increases

Timing and Information Theory Models Temporal coding Hypothesis In addition to forming a CS-US association Learn the temporal CS – US pattern and US - US pattern For example timing of conditioned eyeblink see fig 3.9 Sexual condition where CS-US interval influences conditioned see fig 4.9 Can also learn the inter trial interval (ITI) which indicates frequency of US Relative waiting time hypothesis Knowledge of both CS-US interval and US-US interval predicts the ratio of the ISI to ITI ISI also called trial duration or just “T “ how long you wait for US during CS ITI : is shortened to just “I” how long you wait from US to US ITI / ISI is the I/T ratio I/T ratio Low ratios provide less information about timing of CS-US High ratios provide good predictions of the CS-US relationship See figure 4.21

FIGURE 4.21 T is CS – US interval I = 120 sec T = 20 sec I = 60 sec Percentage of time rats spent nosing the food cup during an auditory CS in conditioning with either a 10-second or a 20-second trial duration (T) and various intertrial intervals (I) that created I/T ratios ranging from 1.5 to 48.0. Data are shown in relation to responding during baseline periods when the CS was absent. (Based on “Trial and Intertribal Durations in Appetitive Conditioning in Rats,” by P. C. Holland, 2000, Animal Learning & Behavior, Vol. 28, Figure 2, p. 125.) T is CS – US interval I = 120 sec T = 20 sec I = 60 sec T = 10 sec I is US – US interval The Principles of Learning and Behavior, 7e by Michael Domjan Copyright © 2015 Wadsworth Publishing, a division of Cengage Learning. All rights reserved.