Contextual control of discriminated operant behavior.

A comparison of neuronal reactions during classical and instrumental conditioning under similar conditions

Behavioral momentum theory has evolved within the realm of operant conditioning. The thought-provoking momentum metaphor equates the strength of an operant response with its resistance to change and preference (i.e., choice) for that response over other available responses. Whereas baseline response rate (velocity in the metaphor) is assumed to be largely influenced by the response-reinforcer contingency, resistance to change and preference are assumed to reflect an intervening variable called behavioral mass, which is determined primarily by the stimulus-reinforcer relationship. This invites the question of how well the momentum metaphor applies to the stimulus-reinforcer relationships of traditional Pavlovian paradigms. Presumably, a correspondence exists between behavioral mass and the notion of associative strength in the associative learning literature. Although response rate has little meaning in the trialwise structure of classical (i.e., Pavlovian) conditioning, response probability or magnitude might be regarded metaphorically as velocity. Momentum theory suggests that resistance to change (e.g., extinction) is a better indicator of associative strength than is response probability or magnitude. Therefore, variables that strengthen Pavlovian learning should influence resistance to extinction of conditioned responding in a similar manner. Moreover, it is important to assess momentum theory outside of strictly operant paradigms, particularly because in clinical settings many common disorders (e.g., phobias) and their therapies (e.g., cue exposure) are thought to be classically conditioned.

Conditioned lick suppression by water-deprived rats was used to elaborate on recent evidence that the attenuated conditioned response elicited by an overshadowed stimulus may be enhanced by extinction of the overshadowing stimulus with which it had been trained in simultaneous compound. Using a modified serial stimulus arrangement in which a light coexisted with the last half of a tone that terminated with footshock, it was found in Experiment 1 that the tone overshadowed the light. Extinction of the tone-shock association resulted in a virtually complete recovery of the response to the overshadowed light. Using this serial overshadowing procedure, the possibility that the strength of a conditioned response to an element trained in compound covaries as a function of the strength of the response to the other element was tested in Experiment 2. Following overshadowing training similar to that of Experiment 1, independent reinforcement of the overshadowed light, that is, associative inflation, was found to have no deleterious effect on the response to the overshadowing tone. This suggests that the effects of postconditioning extinction and inflation of one element do not have symmetrical effects upon responding to the other element. The results of Experiment 2 were replicated in Experiment 3 using a simultaneous compound stimulus as opposed to the serial compound of the previous studies. These results are discussed in terms of various associative and cognitive models of learning and performance.

The cockroach, Leucophaea maderae, can be trained in an associative olfactory memory task by either classical or operant conditioning. When trained by classical conditioning, memory formation is regulated by a circadian clock, but once the memory is formed, it can be recalled at any circadian time. In contrast, when trained via operant conditioning, animals can learn the task at any circadian phase, but the ability to recall the long-term memory is tied to the phase of training. The optic lobes of the cockroach contain a circadian clock that drives circadian rhythms of locomotor activity, mating behavior, sensitivity of the compound eye to light, and the sensitivity of olfactory receptors in the antennae. To evaluate the role of the optic lobes in regulating learning and memory processes, the authors examined the effects of surgical ablation of the optic lobes on memory formation in classical conditioning and memory recall following operant conditioning. The effect of optic lobe ablation was to "rescue" the deficit in memory acquisition at a time the animals normally cannot learn and "rescue" the animal's ability to recall a memory formed by operant conditioning at a phase where memory was not normally expressed. The results suggested that the optic lobe pacemaker regulates these processes through inhibition at "inappropriate" times of day. As a pharmacological test of this hypothesis, the authors showed that injections of fipronil, an antagonist of GABA and glutamate-activated chloride channels, had the same effects as optic lobe ablation on memory formation and recall. The data suggest that the optic lobes contain the circadian clock(s) that regulate learning and memory processes via inhibition of neural processes in the brain.

US habituation, like CS extinction, produces a decrement in conditioned fear responding that is NMDA dependent and subject to renewal and reinstatement

In 2 experiments, the effect of anxiety on the cued-unconditioned stimulus (UCS) rehearsal phenomenon was investigated (T. Jones & G. C. L. Davey, 1990). In Experiment 1, postconditioning rehearsal of the unconditioned stimulus (UCS) resulted in an increase in conditioned response (CR) strength during extinction, but only in subjects with high levels of trait anxiety. An induced mood procedure was used in Experiment 2, and a postrehearsal increase in CR strength was found in subjects who had undergone induced somatic anxiety but not in subjects who had undergone induced worrying or who underwent a neutral induction procedure. In both experiments, the increase in CR strength following UCS rehearsal was associated with inflated ratings of the aversiveness of rehearsing the UCS. These results are discussed in terms of the ways in which anxiety might influence UCS rehearsal and facilitate physiological CRs to the conditioned stimulus.

According to the behavioral momentum theory of response strength (Nevin et al., Journal of the Experimental Analysis of Behavior, 53, 359–379, 1990), steady-state responding reflects the contingency between a response and a reinforcer (response–reinforcer relationship), whereas behavior’s resistance to change is mediated by a contingency between a stimulus and the reinforcer (stimulus–reinforcer relationship). It is further presumed in this theory that a Pavlovian conditioned stimulus (CS)–unconditioned stimulus (US) contingency overlaps with the discriminative stimulus (SD), signaling a primary reinforcer (SR+) within the 3-term contingency (SD: response [R]–SR+). The mere arranging of a stimulus–reinforcer relation in an operant preparation, however, does not necessarily imply that the resulting behavioral process is Pavlovian. This article questions how important such Pavlovian CS–SR+ relations really are in governing operant behavior and its resistance to change in view of evidence from the operant and Pavlovian literatures showing dissociation between Pavlovian and operant stimulus control. To this end, we highlight studies published in the Pavlovian associative literature (Holman and Mackintosh, The Quarterly Journal of Experimental Psychology Section B: Comparative and Physiological Psychology, 33, 21–31, 1981; Rescorla, Current Directions in Psychological Science, 1, 66–70, 1992b) as well as at least 1 seldom-cited study published in the Journal of the Experimental Analysis of Behavior (Marcucella, Journal of the Experimental Analysis of Behavior, 36, 51–60, 1981) supporting the view that CS relations embedded in the 3-term operant contingency can act independently of the discriminative stimulus functions of the SD. These CS relations appear to be neither necessary nor sufficient for sustaining operant discriminative control. Pavlovian relations are likely to be artifacts of operant conditioning—not causal mediators. It is suggested that continued and excessive focus on Pavlovian processes that only have meager influence on operant behavior in general, and behavioral momentum more specifically, will likely be an empirical cul-de-sac for improvement of behavioral management for addiction relapse and other behavioral disorders.

Is behaviorism false because there is no such thing as conditioning? Popper and skinner on learning

Electrophysiological CNS-processes related to associative learning in humans

Chapter eight - Cognitive Behavioral Treatments for Substance Use Disorders

Chapter 3.1 Brain mechanisms of Pavlovian and instrumental aversive conditioning

Goldfish, trained in the shuttlebox to avoid shock, were tested for the acquisition and extinction of a color-matching or a color-oddity conditional discrimination choice response, and then tested for reacquisition. Extinction affected the accuracy of the choice response but not the number of trials with response (response strength). Half of all groups were extinguished with changed signal colors, and half had the same signal colors experienced in acquisition. All groups had the same signal colors in reacquisition that they had experienced in acquisition. Changed-signal oddity groups decremented slightly faster than same-signal oddity groups, providing some support for a generalization decrement interpretation, but same- and changed-signal matching groups did not differ. All groups extinguished on the choice response by the end of extinction. All matching groups, and all oddity groups, regardless of their respective signal colors in extinction, reacquired at the same rate, and faster than in acquisition. These results imply conceptual generalization of extinction effects. Matching-trained groups were found to be slightly superior to oddity-trained groups in both acquisition and reacquisition. Comparisons of these results to positive reinforcement conditional discrimination extinction work, including some procedural suggestions, are made.

Immunohistochemical assessment of mesotelencephalic dopamine activity during the acquisition and expression of Pavlovian versus instrumental behaviours

Extinguishing a conditioned response (CR) has entailed separating the conditioned stimulus (CS) from the unconditioned stimulus (US). This research reveals that elimination of the rabbit nictitating membrane response occurred during continuous CS-US pairings. Initial training contained a mixture of 2 CS-US interstimulus intervals (ISIs), 150 ms and 500 ms. The CRs showed double peaks, one for each ISI. When the 150-ms ISI was removed, its CR peak showed 2 hallmarks of extinction: a decline across sessions and spontaneous recovery between sessions. When a further stage of training was introduced with a distinctive CS using the 150-ms ISI, occasional tests of the original, extinguished CS revealed another hallmark of extinction, specifically, strong recovery of the 150-ms peak. These results support both abstract and cerebellar models of conditioning that encode the CS into a cascade of microstimuli, while challenging theories of extinction that rely on changes in CS processing, US representations, and contextual control.

There are currently two computational accounts of how the time to read pseudohomophones (like BRANE) and their nonword controls (like FRANE) varies with changes in context. In Reynolds and Besner's (2005) account, readers vary the breadth of lexical activation in response to changes in context. A competing account proposed by Kwantes and Marmurek (2007) and independently by Perry, Ziegler, and Zorzi (2007) has readers varying their response criterion in response to changes in context. The present work adjudicates between these two accounts by examining how the effect of neighbourhood density changes as a function of list context when reading pseudohomophones aloud. The results of an experiment and simulations from a leading computational model support the lexical breadth account, but are inconsistent with the response criterion account.