Publisher Summary Instead of specifying the notion of information formally, this chapter examines some of the empirical operations and results which have led investigators to the intuition that information matters in conditioning. The chapter then suggests a theory, which acknowledges the importance of these operations in producing conditioning and discuss some empirical assessments of that theory. To the degree that the theory accounts for those operations which suggest the intuition of information, it can be viewed as an explication of that intuition, however, that notion does not enter into the theory itself. As the theory is explored, a number of points are discovered at which it provides a better account of the data than does the original intuition. Consequently, it is suggested that although the informational intuition serves an initially useful purpose, it does not provide an adequate conceptualization around which the understanding of Pavlovian conditioning can be organized.

Informational Variables in Pavlovian Conditioning

Egger and Miller (1962) hypothesized that the conditioned reinforcing value of stimuli depends on their information value. Egger and Miller and others have tested this hypothesis by comparing the conditioned reinforcing value of S1 and S2 following S1-S2-reward training. However, none of these experiments have controlled for differential generalization of conditioned reinforcement value from training to comparison tests. That is, the S1 cue pattern during the conditioned reinforcement tests has been very similar to the S1 cue pattern of training, while the training and test S2 cue patterns have been quite dissimilar. In Experiment 1, pigeons in a procedure unconfounded by differential generalization produced S2 reliably more frequently than S1, and pigeons in a confounded procedure produced S1 somewhat more frequently than S2. A significant groups × stimuli interaction was attributed to differential stimulus generalization from training to test for S1 and S2 in the confounded condition. In Experiment 2, pigeons in an unconfounded procedure again produced S2 reliably more frequently under a different testing procedure. The results are interpreted as demonstrating that, following S1-S2-food training trials, S2 is the more effective conditioned reinforcer in unconfounded conditions. A reconceptualization of the information hypothesis is shown to be consistent with these results.

https://link.springer.com/content/pdf/10.3758/BF03212045.pdf

Tests of the conditioned reinforcement value of sequential stimuli in pigeons

Three blocking experiments were run using a conditional emotional response procedure with rats as subjects. In each experiment, following initial conditioning to a light stimulus, blocking rats were conditioned to a compound in which a short-duration (30-second) noise was superimposed on the terminal portion of the longer-duration light. In Experiment 1, the light was always three minutes in duration; in Experiment 2, the light was switched from a constant (three-minute) to a variable (0.5–5.0 minute) duration at the start of compound conditioning; in Experiment 3, the light was variable in duration throughout conditioning. Control rats received the same compound conditioning experiences as the blocking rats but did not receive prior conditioning to the light by itself. These temporal manipulations had strong and systematic influence on the rats’ pattern of responding during compound conditioning. Most notably, experience with a constantduration light resulted in both blocking and compound animals showing little conditional suppression to the early conditional stimulus portion of light by itself, followed by strong conditional suppression to the terminal 30 seconds of light plus noise. When testing was done with the noise in isolation subsequent to compound conditioning, however, an equally strong blocking effect was obtained across all the temporal manipulations. In all cases, the blocking animals showed much less conditional suppression to the noise than did the compound control animals. This lack of correspondence between the rats’ responding during compound conditioning and their response to the noise by itself is theoretically puzzling. The confounding effect of inhibition of delay may provide at least a partial explanation of this pattern of results.

Blocking and nonsimultaneous compounds: Comparison of responding during compound conditioning and testing

The role of CS-US contiguity in classical conditioning of the rabbit's nictitating membrane response to serial stimuli

The Egger-Miller information hypothesis was tested in a nonoverlapping compound stimulus CER situation. During CER training, S2, the so-called redundant stimulus, acquired greater suppression qualities than S1. However, following CER training, subjects were exposed to test situations in which the independent suppression qualities of S1 and S2 were assessed. S1 was followed by a trace interval, S2 was presented alone, or the S1–S2 sequence was reversed. Results of all test conditions showed minimal suppression to S2, while suppression to S1 was maintained or facilitated. It was suggested that S2, although a redundant predictor of shock occurrence, provides information as to “when” shock is due.

/pdf/the-informational-properties-of-s1-s2-and-the-s1-s2-sequence-2sk9tvb9zh.pdf

The informational properties of S1, S2, and the S1–S2 sequence on conditioned suppression

The Egger-Miller information hypothesis was tested in the CER situation using a nonoverlapping compound conditioning procedure. Six rats were given both delayed and compound conditioning trials consisting of identical CS-US intervals. The findings provided no support for the hypothesis, and further indicated that temporal factors contributed only partially to attenuated suppression in S1.

/pdf/temporal-vs-discriminative-factors-in-the-maintenance-of-10o58m92ey.pdf

William H. Keeter

Papers

Temporal vs discriminative factors in the maintenance of conditioned suppression: A test of the information hypothesis