Study 5: Associations in Second Order
Conditioning

22 February 1999

Abstract

In the first stage of this study, each rat will receive a continuation of last week's second order training. Then, each rat will be placed into one of two groups. The first group will receive extinction training to the first order CS. The second will receive continued pairings with the US. The effects of these two manipulations will be used to infer the nature of the association between the second and first order CS.

Introduction

In this study, we will attempt a manipulation that historically played an important role in the analysis of associative processes. The issue is actually an old one: What do animals learn in a Pavlovian conditioning procedure? Some theories of learning assume that what is learned is a response process; others assume that some stimulus process is associated. In general, the debate relied more on polemics than it did on real data.

In 1958, Rozeboom suggested a direct empirical test of the two alternatives. Basically, Rozeboom proposed that the issue should be rephrased into the question: Does the CS resemble the response made during conditioning, or does it resemble the response elicited by the US? Unfortunately, no one at the time followed up Rozeboom's suggestion (although Konorski and his students published a little-noticed paper using the same procedure).

Later, Rizely and Rescorla (1972) tried out a procedure in second order conditioning using Rozeboom's test. Their procedure was a simple one: after conditioning a second-order stimulus to elicit a CS, extinguish the first order stimulus. If the second-order CS was affected by this extinction, then one would have evidence that second-order conditioning was mediated by first-order associations. Rizley and Rescorla found that the second-order response was completely unaffected by extinction of the first-order reinforcer; this implied to them that second-order conditioning was a form of learning involving stimulus-response associations.

Rizley and Rescorla's procedure has been applied to a number of different conditioning situations, including activity conditioning with food (Holland and Rescorla, 1975a). In our study for this week, we will attempt a partial replication of Holland and Rescorla's experiment, using behavioural categories rather than activity counts. Please read the Holland and Rescorla (1975a) paper. Also included in the references is a companion paper (Holland and Rescorla, 1975b) that shows how this paradigm can be applied to analyze first order conditioning.

Methods

Subjects:

Our Sprague-Dawley rats will serve as subjects.

Apparatus:

We will be using the six custom-constructed chambers to condition our animals and the tone and light stimuli from our previous study.

Behavioural Coding:

As before, we will use Holland's (1977) behavioural coding categories. Record behaviours from the first and second part of each stimulus.

Procedure:

Each rat will be run for a session of 84 minutes. During the first 36 minutes (Phase I) we will continue the second-order conditioning training given the rats in Study Four. Then, during the next 40 minutes (Phase II) half the animals will be given extinction of the first-order stimulus; the other half will continue to receive reinforcement of the first-order stimulus. Lastly (Phase III), all animals will be given tests of the second-order stimulus.

During Phase I deliver 12 second-order trials and 6 first-order trials in the order SSFFSS FSSFSS SFSFSS according to the contingency used with your rat last week. Deliver a trial every two minutes.

During Phase II deliver 20 trials of the first-order stimulus. Deliver or withold reinforcement of the first-order stimulus dependiong upon whether you have been assigned as the reinforcement or the extinction group (group assignments will be made in class). Deliver the stimuli every two minutes.

Finally, give your rat four trials of the second-order stimulus alone. Do not give the first-order stimulus (why?).

After the session, weigh and feed your rat.

Results

This study differs from the others in that we are expecting a between-group difference. I would, therefore, like to pool the data from all the rats. We will construct a classroom "data sheet" for you to record your rat's data on. Your analysis should use the full set of data.

We can first examine whether we have achieved second-order conditioning. Compare performance to the second-order stimulus over the block fo four trials at the end of training to perforance over the four trials at the start (please bring the data from Study 4 to class for this comparison). We will also need to know whether we have extinguished responding to the first-order cue; therefore, compare performance during the first block of four extinction trials to performance during the last block.

Finally, consider the effect of this extinction. The central issue is whether the two treatments (extinction vs. continued reinforcement) differentially affected conditioned responses to the second-order cue. How can this issue be tested? Decide on a means of testing this question and present your conclusions.

References

Required:

Holland, P.C. and Rescorla, R.A. (1975a). Second-order conditioning with food unconditioned stimulus. Journal of Comparative and Physiological Psychology, 88: 459-467.

Study 5: Associations in Second Order Conditioning