The Rescorla-Wagner Model of Classical Conditioning


By following this link you will be taken to a page with an applet that allows you to interact with the Rescrola-Wagner Model of the classical conditioning.  On this page, I will describe the interface to the model.  If I ever have time I will add a more thorough discussion of the model.

The basics of the model is the prediction of learning in a classical conditioning based upon several parameters: the Salience (S) of various CSs, the current strength of the US (A), the strength of the association between the various CS and the US (V) and the total learned association between all of the present CS and the US (V sum).  On each trial the change in the associative strength between a CS and the US is determined by the following equations

DVi = Si x (A - V sum)

where i indicates the particular CS.  Salience is between 0 and 1 and the rest of the values are arbitrary.

In this model, there are two CSs that can be presented, a tone and a light.  You control the salience of the CSs by sliders on the left hand side of the screen.  You can also control the strength of the US (0 being a test trial) with the right hand slider. 

There are three graphs to help you follow the actions of the model.  The two top graphs are bar graphs and indicate the predictions for a particular trial, and the current state of learning, respectively.  The prediction graph shows the predicted change of associative strength of the two CSs and the discrepancy between the US strenght (A) and the expectation of a US from the CSs (V sum) - this value is A- V sum.  The current state graph is the current associative strength for the two CSs and over all.  On both of the bar graphs, the gray horizontal line in the middle represents a zero change or associative value.  Bars going up from that line indicated positive change or positive associative strength.  Bars going down are negative changes or negative associative strength (indicating conditioned inhibitors).  The bottom graph is a line graph that shows the history of conditioning for the associate strength of the two CSs and V sum. 

As you set the values for the salience of the CSs and the strenght of the US you can see what might happen in the trial.  To run the trial press the RUN TRIAL button.  To start over, press the RESET button.  These buttons are located on the left side below the sliders.

Go to the applet.