The effects of physical context changes and multiple extinction contexts on two forms of renewal in a conditioned suppression task with humans

Three experiments examined the effects of physical context changes and multiple extinction contexts on the renewal of conditioned suppression in humans. A conditioned suppression task used an undesirable event as the unconditional stimulus (US). One conditional stimulus (CS+) predicted the occurrence of the US and another (CS−) predicted US absence. In Experiment 1 (N = 32), conditioned suppression was acquired to the CS+ in one context and extinguished in a different context. An increase in suppression was found for the CS+ and not for the CS− when subsequent test trials were conducted in the acquisition context (ABA renewal). Experiment 2 (N = 32) tested for ABC Renewal and showed increased suppression to both the CS+ and CS− when test was conducted in a novel context. Experiment 3 (N = 80) showed that these two effects were abolished when extinction was conducted in multiple contexts. The experiments extend the ABA renewal of conditioned suppression found with non-human animal subjects and the reduction of renewal by extinction in multiple contexts. Context changes may also facilitate cue competition effects after training with elementary stimuli, as shown by the effects of US omission in the ABA and ABC renewal groups.     

The effects of context changes on the reinstatement of extinguished conditioned behavior in a conditioned suppression task with humans

Reinstatement refers to the return of previously extinguished conditioned responses to test trials of a conditional stimulus (CS) when presentations of the unconditional stimulus (US) alone are given following extinction. Four experiments were conducted to determine whether reinstatement could be found in a conditioned suppression task with humans and whether contextual changes can abolish it. Experiment 1 demonstrated the reinstatement of conditioned suppression when acquisition, extinction, US alone, and test trials were all given in the same context. Experiments 2 and 3 suggested that the reinstatement effect was still present when the US alone presentations were given in a different context to the subsequent test trials. Experiment 4 replicated this effect using additional controls over the amount of exposure to the various contexts. The results suggest that reinstatement can be robust across changing contexts. Aspects of the conditioned suppression task that promote the transfer of learning across contexts or the establishment of configural context-CS stimuli may underlie the apparent lack of contextual control over reinstatement.     

Effects of multiple contexts and context similarity on the renewal of extinguished conditioned behaviour in an ABA design with humans

The ABA renewal procedure involves pairing a conditional stimulus (CS) and an unconditional stimulus (US) in one context (A), presenting extinction trials of the CS alone in a second context (B), and nonreinforced test trials of the CS in the acquisition context (A). The renewal of extinguished conditioned behaviour is observed during test. The current study tested the effects of multiple extinction contexts and context similarity in attenuating renewal. Participants (N = 99) took part in a fear conditioning ABA renewal procedure. Using a measure of self-reported expectancy of the US, ABA renewal was observed when a single extinction context that was dissimilar to the test context was used. Renewal was attenuated, though still present, when extinction occurred in multiple dissimilar extinction contexts or in a single extinction context that was similar to the test context. Renewal was completely abolished when multiple extinction contexts that were similar to the test context were combined. Multiple extinction contexts and context similarity act additively in their effect on attenuating renewal. The results are discussed in relation to the design of exposure therapy programs that seek to reduce relapse that can occur via renewal.     

Exposure to a novel context after extinction causes a renewal of extinguished conditioned responses: Implications for the treatment of fear

Renewal gives an experimental model for the relapse of fear symptoms following exposure therapy. While renewal of extinguished fear in humans has been observed following a return to the original context in which fear was acquired (ABA design), it has been more difficult to show upon presentation of a novel context (ABC design). The present experiment used a particularly strong context manipulation in a fear conditioning procedure. Context was manipulated by using large photographs of real environments taken from various angles and was present throughout the entire experiment. A renewal of cognitive expectancy was found in both ABA and ABC renewal designs, although it was larger in the former than in the latter. Response times in making the expectancy judgments increased when there was a change to a new context. The results demonstrate consistency in fear renewal effects between human and animal studies and suggest that relapse following exposure therapy via renewal remains a danger when people encounter a previously feared object in a novel context.     

Unpaired shocks during extinction weaken the contextual renewal of a conditioned discrimination

Extinction is generally more fragile than conditioning, as illustrated by the contextual renewal effect. The traditional extinction procedure entails isolated presentations of the conditioned stimulus. Extinction may be boosted by adding isolated presentations of the unconditioned stimulus, as this should augment breaking the contingency between the two stimuli. In a human conditioning experiment with on-line expectancy ratings and electrodermal responding as dependent variables, 32 participants were differentially conditioned to two neutral figures using electric shock. After a change of context, one group received normal extinction treatment whereas another group received explicitly unpaired presentations of the figures and shock. At test, the two figures were presented in the original context again. For both measures, only the group that received normal extinction showed renewal of the conditioned discrimination. These results suggest that unpaired shocks during extinction strengthen the extinction learning.     

Conducting extinction in multiple contexts does not necessarily attenuate the renewal of shock expectancy in a fear-conditioning procedure with humans

The renewal of Pavlovian-conditioned responses may provide a model for the relapse of fear following extinction-based treatments for anxiety disorders. Renewal can be observed if conditional stimulus (CS) and unconditional stimulus (US) pairings are given in one context, extinction trials of CS presentations in a second context, prior to test trials of CS presentations in the original acquisition context (ABA renewal). We examined ABA renewal in humans by using a fear-conditioning procedure with an unpleasant shock US. A renewal of rated shock expectancy was demonstrated with this procedure. Conducting extinction treatment in multiple contexts was expected to attenuate the renewal effect. However, the renewal of shock expectancy persisted when extinction treatment was given across three or five different contexts. With the current renewal design, learning task, and measure of conditioned behaviour, extinction treatment does not appear to readily generalise to the test context. The use of multiple extinction treatments in a clinical setting may not necessarily reduce the likelihood of relapse via a renewal effect.     

Extensive extinction in multiple contexts eliminates the renewal of conditioned fear in rats

Two studies examined whether nonreinforcement of a stimulus in multiple contexts, instead of a single context, would decrease renewal of conditioned fear in rats (as assessed by conditioned suppression of lever pressing). In Experiment 1, renewal was measured after 36 nonreinforced CS trials delivered during six extinction sessions in a single context or two extinction sessions in each of three different contexts. The number of extinction contexts did not have an effect on renewal. In Experiment 2, groups received either 36 or 144 nonreinforced CS trials during six or twenty-four extinction sessions in a single context or three different contexts. Again, renewal was not influenced by the number of extinction contexts when only 36 trials were given. However, when 144 trials were used, renewal was completely eliminated when extinction was divided between 3 contexts, but was not weakened when the sessions took place in a single context. The results suggest that the use of multiple treatment settings in exposure-based therapies is only likely to reduce relapse if a sufficient number of sessions are provided in each of the treatment settings.     

All we need is a cue to remember: the effect of an extinction cue on renewal

In the present study, it was investigated by employing a human fear conditioning paradigm whether an extinction retrieval cue can attenuate renewal of conditioned responding after an extinction treatment procedure, and if so, what the precise role of such an extinction cue comprises. It was hypothesized that such a cue can attenuate renewal and would function as a safety signal capable of directly inhibiting the expectancy of an aversive outcome and conditioned skin conductance responding to a conditioned stimulus. The results demonstrated that the extinguished expectancy of an aversive outcome was renewed when the CS was presented outside the extinction context and that an extinction cue attenuated this effect. This extinction cue, however, only transferred its inhibitory properties to other, non-extinguished stimuli when there was no contextual switch. This safety signal function was not observed after a switch in context. Possible functions of the extinction cue and its application in extinction-based exposure treatments are discussed.     

The repeated confrontation with videotapes of spiders in multiple contexts attenuates renewal of fear in spider-anxious students

In a treatment-analogue experiment, extinction of fear of spiders was investigated in a group of spider-anxious students. Two groups were created: in the single extinction group the extinction trials consisted of repeated presentations of a videotaped spider in one specific location of a house, whereas in the multiple extinction group the trials consisted of videotapes of the same spider in three different locations of a house. Also a control group was included that was exposed to videotapes of the location but without the spider. As reflected in skin conductance responses and self-report data, fear of spiders was significantly reduced in the two extinction groups compared to the control group. Moreover, when the extinction groups were confronted with the videotape of the spider in a new location, the single extinction group did not show generalisation of extinction, whereas the multiple extinction group did. These results corroborate the existing evidence for context dependence of extinction of fear and provide new evidence that the use of multiple contexts during extinction might improve the generalisability of extinction in humans. Implications for exposure therapy are discussed.     

The renewal of extinguished conditioned fear with fear-relevant and fear-irrelevant stimuli by a context change after extinction

The acquisition, extinction, and subsequent recovery of conditioned fear can be influenced by the nature of the conditional stimulus (CS) and the context in which the CS is presented. The combined effects of these factors were examined in a differential fear-conditioning procedure with humans. Fear-relevant or fear-irrelevant CSs were followed by a shock unconditional stimulus (US) during acquisition and presented alone during extinction. The CSs were images presented upon different background contexts. Half the participants received the same context during acquisition and extinction and the remaining received different contexts. All participants received test trials in the same context as acquisition. In Experiment 1 (N=64), a renewal of shock expectancy and skin conductance responses was found during test for fear-relevant and fear-irrelevant CSs when extinction was given in a different context. In Experiment 2 (N=72), renewal for fear-relevant stimuli was enhanced when acquisition and test was given in an indoor office context and extinction in an outdoor bush context. The opposite context configuration produced the strongest renewal for fear-irrelevant stimuli. The return of extinguished conditioned fear can occur to fear-relevant stimuli that are commonly associated with clinical fears and its strength may be enhanced when the stimuli are encountered in certain contexts after extinction.     

Cross-modal transfer of conditioned suppression in rats: Effects of US intensity and extinction of the initial conditioning task

In conditioned suppression of water licking behavior by rats, we obtained data indicating general transfer of fear conditioning. A series of experiments resulted in two major findings. First, pairing of a neutral stimulus with a shock in the initial conditioning task facilitated acquisition of subsequent fear conditioning to another neutral stimulus, if the conditioned fear of the initial task was extinguished prior to the second task and if equally strong shocks were employed in both conditioning tasks. Second, omission of the extinction treatment or employment of weaker shocks in the initial task resulted in retardation, rather than facilitation, of the second conditioning task. An application to human clinical settings is discussed.     

Postinjection suppression of drinking is modified by the presence of conditioned contextual cues: implications for both anticipatory and posttreatment nausea in humans

In three experiments, we set out to determine whether the response of rats to an injection of LiCl would be modified by the presence of an environmental context that had previously been paired with LiCl. Experiment 1 confirmed that one feature of the malaise produced by LiCl is a reduced tendency to consume an otherwise palatable flavor. Experiment 2 showed that the size of this response was enhanced if it was measured in the presence of a conditioned context. In Experiment 3, we investigated the possibility that the postinjection response could be modified by an overshadowing treatment given during the conditioning phase. The significance of these findings for the understanding of chemotherapy-induced nausea in the clinical population is discussed.     

Constraints on enhanced extinction resulting from extinction treatment in the presence of an added excitor

Three Pavlovian fear conditioning experiments with rats as subjects explored the effect of extinction in the presence of a concurrent excitor. Our aim was to explore this particular treatment, documented in previous studies to deepen extinction, with novel control groups to shed light on the processes involved in extinction. Relative to subjects extinguished on the target CS alone, Experiments 1 and 2 found across a range of parameters that any appreciable effect of facilitated extinction due to the concurrent excitor was submerged by generalization decrement going from extinction to testing. In Experiment 3 we used different durations for the target and concurrent stimuli in order to discourage configuring and an ABC renewal design to increase sensitivity, and observed diminished renewal resulting from extinction in the presence of a second excitor. Our findings suggest that there are distinct limits to the observation of enhanced extinction in the presence of an excitor and identifies some of the sources of these limitations.     

The role of contextual cues in mediating transfer

An experiment was conducted with sceond-grade children to test the hypothesis that contextual (task format) changes limit the transfer of learning. The Ss learned two problems employing different formats concurrently and were then given a single transfer problem similar in format to one of the training problems. The transfer data were predictable from a consideration of the similar format training problem and independent of the different format training problem. This indicated that contextual cues were stored during training and played a role in determining transfer.     

A new tool for assessing context conditioning induced by US-unpredictability in humans: The Martians task restyled

Unpredictability of an unconditioned stimulus (US) typically produces context conditioning in animals and humans. We modified the Martians task - a computer game measuring learning of Pavlovian associations through conditioned suppression - for assessing context conditioning in humans. One between-subjects and one within-subjects study are reported. Both experiments comprised four conditions: a predictable (Paired) condition in which the conditioned stimulus (CS) signaled the US, a neutral condition (No-US), one unpredictable condition in which the CS did not signal the US (Unpaired) and another one in which only unsignaled, temporally unpredictable USs were presented (US-only). Results showed more contextual conditioned suppression in the unpredictable conditions compared to the predictable condition. In contrast, more cued conditioned suppression occurred in the Paired condition than in the Unpaired condition. Consistent with animal research, context conditioning was increased by unpredictability. These data support the Martians task as a promising tool to extend research on human context conditioning.     

Explicit disassociation of a conditioned stimulus and unconditioned stimulus during extinction training reduces both time to asymptotic extinction and spontaneous recovery of a conditioned taste aversion

Conditioned taste aversions (CTAs) may be acquired when an animal consumes a novel taste (CS) and then experiences the symptoms of poisoning (US). This aversion may be extinguished by repeated exposure to the CS alone. However, following a latency period in which the CS is not presented, the CTA will spontaneously recover (SR). In the current study we employed an explicitly unpaired extinction procedure (EU-EXT) to determine if it could thwart SR of a CTA. Sprague-Dawley rats acquired a strong CTA after three pairings of saccharin (SAC the CS) and Lithium Chloride (LiCl the US). CTA acquisition was followed by extinction (EXT) training consisting of either (a) CS-only exposure (CSO) or (b) exposure to saccharin and Lithium Chloride on alternate days (i.e., explicitly unpaired: EU). Both extinction procedures resulted in ?90% reacceptance of SAC, although the EU extinction procedure (EU-EXT) significantly decreased the time necessary for rats to reach this criterion (compared to CSO controls). Rats were subsequently tested for SR of the CTA upon re-exposure to SAC following a 30-day latency period of water drinking. Rats that acquired a CTA and then underwent the CSO extinction procedure exhibited a significant suppression of SAC drinking during the SR test (as compared to their SAC drinking at the end of extinction). However, animals in the EU-EXT group did not show such suppression in drinking compared to CSO controls. These data suggest that the EU-EXT procedure may be useful in reducing both time to extinction and the spontaneous recovery of fears.     

The role of context specificity in learning: the effects of training context on explosives detection in dogs

Various experiments revealed that if an animal learns a stimulus–response–reinforcer relationship in one context and is then tested in another context there is usually a lessening of stimulus control, and the same discriminative stimuli that reliably controlled the behavior in the first context will have less effect in the new context. This reduction in performance is known as the context shift effect. The effect of changing context on the probability of detecting explosives was investigated in seven highly trained explosives detection dogs (EDDs). In experiment 1 the dogs were trained alternately on path A, which always had five hidden explosives, and on a very similar path B, which never had any explosives. Within a few sessions the dogs showed a significant decrease in search behavior on path B, but not on path A. In experiment 2 the same dogs were trained only on path B with a target density of one explosive hidden every 4th day. The probability of the dogs now detecting the explosive was found to be significantly lower than in experiment 1. In experiment 3 the effect of the low target density as used in experiment 2 was investigated on a new but very similar path C. Both the detection probability for the one explosive every 4th day on the new path and the motivation to search were significantly higher than found in experiment 2. Finally, in experiment 4, an attempt was made to recondition the dogs to search on path B. Although trained for 12 daily sessions with one explosive hidden every session, the dogs failed to regain the normal levels of motivation they had shown on both new paths and on the paths that they knew usually contained explosives. The findings reveal that even a very intensively trained EDD will rapidly learn that a specific stretch of path does not contain explosives. The dog will then be less motivated to search and will miss newly placed targets. This learning is specific to the formerly always-clean path and is to some extent irreversible. However, the dog will search and detect normally on new paths even if they are very similar to the always-clean path. The data are discussed in terms of variables affecting renewal. The results suggest that following training designed to make a behavior context independent, any extinction training will not generalize beyond that specific context used during the extinction training. In addition, if the behavior is extinguished in a specific context, it will be very difficult to restore that behavior in that context. These conclusions should be considered by anyone attempting to extinguish well-established trans-context behaviors.This research reports portions of a doctoral dissertation submitted by Irit Gazit to Tel Aviv University.     

Contextual control of human fear associations in a renewal paradigm

The original model of behavior change suggests that extinction is context dependent whereas fear acquisition is context independent [Bouton, M. E. & Ricker, S. T. (1994). Renewal of extinguished responding in a second context. Animal Learning and Behavior, 22, 317-324]. Supportive evidence stems mainly from animal studies, showing that after acquisition (conditioned stimulus-unconditioned stimulus (CS-US)) in Context A and extinction in Context B, fear is renewed by presenting the CS in acquisition Context A (ABA renewal) or in a novel Context C (ABC renewal). By implication, the model predicts equal ABA and ABC renewal. However, there is also evidence to suggest that the context dependency of extinction and the context independency of acquisition may be less stringent than originally proposed. The present study investigated renewal in humans using a differential fear conditioning paradigm with a shock US and online shock expectancy ratings and electrodermal responses as dependent variables. Experiment 1 compared an ABA condition with an AAA condition. Experiment 2 compared three conditions: ABA, ABC, and AAA. Both experiments demonstrated ABA renewal. Most importantly, Experiment 2 showed larger ABA than ABC renewal. Overall, results for expectancy ratings were more convincing than for electrodermal responses. In line with the extinction model, the present findings support the context dependency of extinction in humans. In contrast to the model, the findings suggest that in humans not only extinction learning, but also fear acquisition is controlled by its current context.     

Use of the ABA fear renewal paradigm to assess the effects of extinction with co-present fear inhibitors or excitors: Implications for theories of extinction and for treating human fears and phobias

In four experiments using albino rats in an ABA fear renewal paradigm, we studied conditioned fear in the A test context following extinction in Context B. Conditioned suppression of operant responding was the index of fear. In Experiments 1-3, we found that extinguishing a feared cue in compound with a putative conditioned inhibitor of fear led to more fear in the test context than did a conventional extinction procedure. In Experiments 4a and 4b, we found that extinguishing three feared cues in compound required one third the time and generally led to less fear to the cues in the test context than did the extinction of each cue separately. Thus, fear in the test context seems to vary inversely with the values of co-present cues during extinction in Context B. Results imply that cue value is actually reduced by extinction procedures rather than merely being opposed by a growing inhibitory process. Implications for theories of renewal and for clinical practice are discussed.     

The role of contextual cues in the haptic perception of orientations and the oblique effect

Blindfolded right-handed participants were asked to position, with the right hand, a frontoparallel rod to one of three orientations: vertical (0°) and left 45° and right 45° obliques. Simultaneously, three different backgrounds were explored with the left hand: smooth, congruent stripes (parallel to the orientation to be produced), or incongruent stripes (tilted relative to the orientation to be produced). The analysis of variable errors showed that the oblique effect (higher precision for the vertical orientation than for the oblique orientations) was weakened in the presence of contextual cues, because of an improvement in oblique precision. Moreover, the analysis of constant errors revealed that the perception of orientations erred in the direction of the stripes, similar to the effect that has been found with vision, where visual contextual cues (tilted frame or lines) divert the perception of the vertical. These results are discussed in relation to a patterncentric frame of reference hypothesis or as a congruency effect.