In this article I review research and theory on the "interference paradigms" in Pavlovian learning. In these situations (e.g., extinction, counterconditioning, and latent inhibition), a conditioned stimulus (CS) is associated with different unconditioned stimuli (USs) or outcomes in different phases of the experiment; retroactive interference, proactive interference, or both are often observed. In all of the paradigms, contextual stimuli influence performance, and when information is available, so does the passage of time. Memories of both phases are retained, and performance may depend on which is retrieved. Despite the similarity of the paradigms, conditioning theories tend to explain them with separate mechanisms. They also do not provide an adequate account of the context's role, fail to predict the effects of time, and overemphasize the role of learning or storage deficits. By accepting 4 propositions about animal memory (i.e., contextual stimuli guide retrieval, time is a context, different memories are differentially dependent on context, and interference occurs at performance output), a memory retrieval framework can provide an integrated account of context, time, and performance in the various paradigms.

Context, time, and memory retrieval in the interference paradigms of Pavlovian learning.

That all events are equally associable and obey common laws is a central assumption of general process learning theory. A continuum of preparedness is denned which holds that organisms are prepared to associate certain events, unprepared for some, and contraprepared for others. A review of data from the traditional learning paradigms shows that the assumption of equivalent associability is false: in classical conditioning, rats are prepared to associate tastes with illness even over very long delays of reinforcement, but are contraprepared to associate tastes with footshock. In instrumental training, pigeons acquire key pecking in the absence of a contingency between pecking and grain (prepared), while cats, on the other hand, have trouble learning to lick themselves to escape, and dogs do not yawn for food (contraprepared). In discriminatio n, dogs are contraprepared to learn that different locations of discriminativ e stimuli control go-no go responding, and to learn that different qualities control directional responding. In avoidance, responses from the natural defensive repertoire are prepared for avoiding shock, while those from the appetitive repertoire are contraprepared. Language acquisition and the functional autonomy of motives are also viewed using the preparedness continuum. Finally, it is speculated that the laws of learning themselves may vary with the preparedness of the organism for the association and that different physiological and cognitive mechanisms may covary with the dimension. Sometimes we forget why psychologists ever trained white rats to press bars for little pellets of flour or sounded metronomes followed by meat powder for domestic dogs. After all, when in the real world do rats encounter levers which they learn to press in order to eat, and when do our pet dogs ever come across metronomes whose clicking signals meat powder ? It may be useful now to remind ourselves about a basic premise which gave rise to such bizarre endeavors, and to see if we still have reason to believe this premise.

On the generality of the laws of learning

The history of 2-process learning theory is described, and the logical and empirical validity of its major postulates is examined. The assumption of 2 acquisition processes requires the demonstration of an empirical interaction between 2 types of reinforcement contingencies and (a) response classes, (b) reinforcing stimulus classes, or (c) characteristics of the learned behavior itself. The mediation postulates of 2-process theory which argue that CRs are intimately involved in the control of instrumental responding are emphasized, and 2 major lines of evidence that stem uniquely from these postulates are examined : (a) the concurrent development and maintenance of instrumental responses and conditioned reflexes, and (b) the interaction between separately conducted Pavlovian conditioning contingencies and instrumental training contingencies in the control of instrumental behavior. The evidence from concurrent measurement studies provides, at the very best, only weak support for the mediational hypotheses of 2-process theory. In contrast, the evidence from interaction studies shows the strong mediating control of instrumental responses by Pavlovian conditioning procedures, and demonstrates the surprising power of Pavlovian concepts in predicting the outcomes of many kinds of interaction experiments.

Two-process learning theory: Relationships between Pavlovian conditioning and instrumental learning

https://webs.wofford.edu/pittmandw/psy230/lab/koch.pdf

The neurobiology of startle.

Weak lead stimulation can modify the human startle reflex It is proposed that, with the aid of physiological measures taken in the interval between lead and startle stimuli, this paradigm offers a promising method of investigating different levels of central processing, the operation of a short time-constant as opposed to a long time-constant system, and the operation of an orienting-Attentional as apposed an Intensity dependent activational system.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1469-8986.1975.tb01284.x

The More or Less Startling Effects of Weak Prestimulation

A progression for generating variable-interval schedules.

Six rats were exposed to a sequence of gunshot-like acoustical bursts during silence, during steady noise, and during pulsed noise. Assessment of their startle reactions to the bursts revealed that a background of steady noise enhanced the response, whereas a background of pulsed noise produced suppression of response. It is hypothesized that pulsed noise causes a relative refractory state in the mechanisms responsible for startle and that steady noise may enhance startle by masking uncontrolled punctiform acoustic stimuli.

https://science.sciencemag.org/content/sci/141/3584/928.full.pdf

Startle reaction: modification by background acoustic stimulation.

/pdf/discriminated-bar-press-avoidance-2s9bykkmv4.pdf

Discriminated bar-press avoidance.

Three years ago a tone ending in unavoidable electrical shock was periodically presented to pigeons while they pecked a key for food. When pecking was disrupted by tone, shock was disconnected and the training tone as well as tones of different frequencies were presented. At first, all tones caused a reduction in the rate of pecking, but as testing proceeded, suppression began to extinguish and the gradient narrowed. In the present work, testing was resumed after a 2½-yr interruption. Analysis of the gradients obtained just before and just after the interruption yielded no evidence of changes with the passage of time. As testing proceeded, however, extinction of suppression continued and the gradient all but disappeared. In subsequent experiments with these subjects (Ss) it was found that the presentation of free shocks caused a reappearance of the gradient and that this effect persisted in reduced amount for several sessions after the shock condition was terminated.

/pdf/stimulus-aspects-of-aversive-controls-the-retention-of-kocktrpg2b.pdf

Stimulus aspects of aversive controls: the retention of conditioned suppression.

/pdf/a-relay-sequencing-device-for-scrambling-grid-shock-37h2evpcaz.pdf

Morton Fleshler

Papers

A progression for generating variable-interval schedules.

Startle reaction: modification by background acoustic stimulation.

Discriminated bar-press avoidance.

Stimulus aspects of aversive controls: the retention of conditioned suppression.

A relay sequencing device for scrambling grid shock.