Cognitive manipulation of GSR extinction: Analogues for conditioning therapies

Cognitive determinants of GSR activity during extinction trials were examined following conditioning. Conditioned GSRs extinguished rapidly when subjects were informed the UCS would not again be administered, compared to subjects not given this information. Of greater interest was the finding that (false) high feedback concerning subjects’ responsivity to the Cs+ during extinction served to maintain GSR activity at a higher level than subjects receiving (false) low feedback. The relationship was observed within both information conditions. Implications are drawn for both aversive conditioning therapy and systematic desensitization.     

The effects of false feedback on attributed arousal and rated attractiveness in female subjects1

In an expanded version of the Valins false feedback paradigm, female subjects viewed ten slides of seminude males accompanied by either an increase or no change in amplified heart beats. Heart rate increase slides were rated as both more attractive and more arousing than no-change slides. These two measures were highly correlated, and did not differ significantly in the degree to which they were influenced by feedback. Subjects also showed significantly greater changes in actual heart rate for the increasing feedback slides than for the no-change slides, although the feedback produced no corresponding differences in GSR. Despite the effects on both subjective report and cardiac activity, correlations between these two measures were generally nonsignificant. Subjects classified as high in autonomic perception showed no significant relationship between actual cardiac activity and slide ratings, nor were they more influenced in their ratings by the feedback than subjects low in autonomic perception. Implications for the false feedback paradigm and for current issues in the social psychology and psychophysiology of emotion are discussed.     

The effects of false response feedback on human 'fear' conditioning

This study describes a human electrodermal conditioning experiment in which subjects were given false skin conductance feedback during CS presentation. In comparison with appropriate attentional control groups, subjects who believed they were exhibiting a strong CR did actually emit a greater magnitude CR, while subjects who believed they were exhibiting only a weak CR emitted a significantly lower magnitude CR. When both self-report and behavioural measures of UCS revaluation were taken after conditioning, the evidence suggested that response feedback had not differentially affected subjects evaluation of the aversiveness of the UCS. The results suggest that the response modulating effects of response feedback observed in this and other studies are not caused by response feedback influencing evaluation of the UCS, but they are consistent with the hypothesis that beliefs about the nature of response feedback influence the strength of the UCS representation itself.     

Amygdala and hippocampal activity during acquisition and extinction of human fear conditioning

Previous functional magnetic resonance imaging (fMRI) studies have characterized brain systems involved in conditional response acquisition during Pavlovian fear conditioning. However, the functional neuroanatomy underlying the extinction of human conditional fear remains largely undetermined. The present study used fMRI to examine brain activity during acquisition and extinction of fear conditioning. During the acquisition phase, participants were either exposed to light (CS) presentations that signaled a brief electrical stimulation (paired group) or received light presentations that did not serve as a warning signal (control group). During the extinction phase, half of the paired group subjects continued to receive the same treatment, whereas the remainder received light alone. Control subjects also received light alone during the extinction phase. Changes in metabolic activity within the amygdala and hippocampus support the involvement of these regions in each of the procedural phases of fear conditioning. Hippocampal activity developed during acquisition of the fear response. Amygdala activity increased whenever experimental contingencies were altered, suggesting that this region is involved in processing changes in environmental relationships. The present data show learning-related amygdala and hippocampal activity during human Pavlovian fear conditioning and suggest that the amygdala is particularly important for forming new associations as relationships between stimuli change.     

Nonaware classical conditioning to pictorial facial stimuli in a between-groups paradigm.

The present experiment investigated the effects of aware and nonaware modes of extinction in classical conditioning to facial emotional stimuli. The subjects participated in three different experimental phases. In the first (habituation) phase they were presented with a 500 ms angry face. In the second (acquisition) phase, for half of the subjects the 500 ms face was paired with an aversive noise (experimental group) while for the other half of the subjects the face and the noise presentations were separated by 6-10 s intervals (sensitization control group). In the third (extinction) phase, these two groups were further divided into two subgroups. One subgroup of both the experimental and control group had the face stimulus presented for 30 ms, and immediately masked with a neutral picture. The other two subgroups had the face presented for 500 ms with no mask. The results showed that conditioning only occurred in the experimental subgroups which was indicated by a significant difference between skin conductance responses during habituation and corresponding responses during extinction. Secondly, comparing the experimental and control groups during the extinction phase, a significant conditioning effect was observed for both the aware and nonaware masked modes of extinction for the experimental group. The results suggest that conditioned autonomic responses may be elicited in a nonaware mode.     

Nonaware classical conditioning to pictorial facial stimuli in a between-groups paradigm

The present experiment investigated the effects of aware and nonaware modes of extinction in classical conditioning to facial emotional stimuli. The subjects participated in three different experimental phases. In the first (habituation) phase they were presented with a 500 ms angry face. In the second (acquisition) phase, for half of the subjects the 500 ms face was paired with an aversive noise (experimental group) while for the other half of the subjects the face and the noise presentations were separated by 6–10 s intervals (sensitization control group). In the third (extinction) phase, these two groups were further divided into two subgroups. One subgroup of both the experimental and control group had the face stimulus presented for 30 ms, and immediately masked with a neutral picture. The other two subgroups had the face presented for 500 ms with no mask. The results showed that conditioning only occurred in the experimental subgroups which was indicated by a significant difference between skin conductance responses during habituation and corresponding responses during extinction. Secondly, comparing the experimental and control groups during the extinction phase, a significant conditioning effect was observed for both the aware and nonaware masked modes of extinction for the experimental group. The results suggest that conditioned autonomic responses may be elicited in a nonaware mode.     

Effects of operant conditioning on the GSR

Each of nine Ss was run for 11 daily sessions. Except for the first (operant level) and last two (extinction) sessions, 500-ohm drops in skin resistance were followed by reinforcement (light). These reinforcement periods lasted 20 min and were preceded by 10-min control periods during which no reinforcement was administered. Although the results showed no evidence for operant conditioning of the GSR, they did indicate that increased emission of GSR's occurred during the reinforcement period. This effect was shown to hold for Ss with low operant levels of GSR's but not for Ss with high operant levels.     

The effect of UCS intensity in classical and avoidance GSR conditioning

This study compared GSR avoidance and yoked-control conditioning procedures. Classical conditioning at two UCS intensities was followed by extinction and, two months later, by an avoidance session. Matching of Ss was based on GSR responsiveness and classical conditioning in the first session. The strong UCS led to more rapid reduction in CR latency (due to an increase in number of Ss responding) in the first session, and there was a tendency for maximum CR magnitude to occur in fewer trials with the strong UCS. No UCS-intensity difference in level of responding to the CS or UCS was found in the first session. A greater amount of spontaneous recovery in the second session was found in the strong UCS group. The avoidance and yoked control groups did not differ in CR magnitudes, latencies, or frequencies, nor in UCR magnitudes in the second session. They did differ significantly in the rate of decline in intertriai responses, the decline being more rapid in the avoidance condition.     

A comparison of the effects of vicariously instigated classical conditioning and direct classical conditioning procedures

Two groups of Ss received either two or 16 paired classical conditioning trials beyond the peak CR. A third group received the same stimuli as in the 16 postpeak condition but in an unpaired and random order. The stimuli in all three groups were delivered directly to S. Subsequently, all three groups, including a fourth which was not given any prior direct classical conditioning, were exposed to vicariously instigated classical conditioning. This consisted of havingS observe someone (model) employed byE who received the same CS as was delivered during direct conditioning. The CS was paired with the feigned arm movement of the model, simulating a reaction to shock. This vicarious classical conditioning procedure when compared to direct classical conditioning resulted in smaller GSR magnitudes for both the CRs and UCRs. Previous experience with direct classical conditioning seems to have had an attenuating effect on GSR magnitude during the vicarious situation. A postexperimental questionnaire tended to support the results, and the relationship between the present study and current classical conditioning theory is discussed.     

MODIFICATION OF ACTIVITY LEVEL THROUGH BIOFEEDBACK AND OPERANT CONDITIONING1

The biomotometer, an electronic device that simultaneously measures activity and provides auditory feedback to the subject, was used in combination with material reinforcers in two experiments attempting to modify activity level in children. In the first study the activity level of an 11-year-old highly active boy was decreased below mean baseline during conditioning in a classroom setting. His level of activity returned to baseline when feedback was withdrawn. In the second study, activity level of a 10-year-old hypoactive boy was increased over mean baseline level during conditioning in a free-play setting, and returned to slightly below baseline during five extinction trials. Results of these studies indicate that the biomotometer is a useful instrument for modification of activity level.     

Overlearning and instructional control of extinction of vasomotor responding

In a previous study by the authors, immediate extinction of conditioned vasomotor responding was obtained, under conditions of both continuous and partial reinforcement, when the UCS delivery apparatus was removed and subjects were informed that there would be no further UCS presentations. The present study varied the number of continuous reinforcement trials using the same conditioning procedure. Forty human subjects were randomly divided into two groups, given thermal vasomotor conditioning procedures on either 25 or 100 continuous reinforcement trials. At the onset of extinction half of each group was given traditional noninformed extinction procedures, while the other (informed) half had the thermal stimulator removed. Immediate extinction was obtained in informed subjects given 25 conditioning trials. However, there was no significant reduction of responding in informed subjects given 100 conditioning trials. Consequences for behavior theories and therapies are discussed.     

Glutamate receptors in the medial geniculate nucleus are necessary for expression and extinction of conditioned fear in rats

Auditory fear conditioning requires anatomical projections from the medial geniculate nucleus (MGN) of the thalamus to the amygdala. Several lines of work indicate that the MGN is a critical sensory relay for auditory information during conditioning, but is not itself involved in the encoding of long-term fear memories. In the present experiments, we examined whether the MGN plays a similar role in the extinction of conditioned fear. Twenty-four hours after Pavlovian fear conditioning, rats received bilateral intra-thalamic infusions of either with NBQX (an AMPA receptor antagonist; Experiment 1) or MK-801 (an NMDA receptor antagonist; Experiment 1), anisomycin (a protein synthesis inhibitor; Experiment 2) or U0126 (a MEK inhibitor; Experiment 3) immediately prior to an extinction session in a novel context. The next day rats received a tone test in a drug-free state to assess their extinction memory; freezing served as an index of fear. Glutamate receptor antagonism prevented both the expression and extinction of conditioned fear. In contrast, neither anisomycin nor U0126 affected extinction. These results suggest that the MGN is a critical sensory relay for auditory information during extinction training, but is not itself a site of plasticity underlying the formation of the extinction memory.     

Reaction time task as unconditional stimulus

Nonaversive unconditional stimuli (USs) are seldom used in human classic conditioning of autonomic responses. One major objection to their use is that they produce deficits in electrodermal (ED) second- and third-interval response conditioning. However, a nonaversive reaction time (RT) task that includes feedback of success has been shown to be an effective US while avoiding this disadvantage (Lipp and Vaitl 1988). The present study compared this new RT task (RT-new) with a traditional RT task (RT-old) and with a standard aversive US (shock) in differential classic conditioning of ED, heart rate (HR), and digital pulse volume (DPV) responses. Eight-second-delay differential conditioning was applied in three groups of 12 subjects each. Simple geometric features (square, cross) displayed on a television screen served as conditional stimuli (CS⁺ and CS^?). In acquisition, there were no statistically significant differences among the groups; differential conditioning did occur in HR, first- and second-interval ED responses, and first-interval DPV responses. Separate analyses within each group, however, revealed that there was no second-interval ED conditioning in the RT-old group. During extinction, neither DPV nor second-interval ED conditioning could be obtained, whereas HR and first-interval ED conditioning occurred in each group. In third-interval omission ED responses, RT-old and shock groups exhibited extinction, while response differentiation was maintained in the RT-new group throughout extinction. The RT task including feedback proved to be as reliable a US as a standard aversive US, whereas application of a traditional RT task again yielded some weaknesses in second-interval ED conditioning.     

Pavlovian phenomena in conditioned acceleration—Stimulus summation

Four naive male rats were separately fear-conditioned to two stimuli (light and sound) by pairing these stimuli with shocks. During Sidman avoidance these unreinforced stimuli elicited increases in response rates (conditioned acceleration). In a multiple schedule with light-shock and sound-shock reinforcements in the first component, the rats were tested for summation effects in the second (avoidance) component by presenting the light twice, the sound twice and the compound twice. They were then extinguished by eliminating the shocks in the first component. The effects of compounding were evidenced by: (1) a sizeable and reliable amplitude increase to the compound stimulus during conditioning; (2) a smaller and less consistent decrease in latencies during conditioning in all four subjects; and (3) a greater resistance to extinction for the compound stimulus as measured by mean amplitudes for all four subjects and on six of seven extinction sessions. Latency data during extinction were inconclusive. An additional unexpected finding was what appeared to be a two-factor secondary extinction of the avoidance itself as a result of Pavlovian extinction. The responding in the first four minutes of avoidance was inhibited to such an extent that the number of shocks received during this period increased 700 per cent from the last three conditioning sessions to the first three extinction sessions.     

Avoidance learning in a social situation- extinction resistance and defense reaction under stress. A pilot study

Two successive experiments were conducted resulting from observations of the stability (resistance to extinction) of avoidance reactions and the manifestation of such reactions beyond the specific avoidance conditions in which they were acquired: a) 15 subjects were set the task to avoid an aversive acoustic stimulus for a helpless experimental partner. They could achieve this by reacting with contraction of either the forearm or the calf muscles in a difficult discrimination task. The stability of these avoidance reactions was assessed on different levels of forced extinction. Measures taken were HR, GSR and EMG of the avoidance reactions. Specific courses of the two autonomous measures evolved (Fig. 1,2). 14 of the 15 experimental subjects showed the avoidance behaviour during all phases of forced extinction. b) Six weeks after the experimental subjects had acquired the motor avoidance reactions all subjects were exposed to a relatively unspecific stress situation. Comparisons between experimental and control group (which consisted of the experimental partners) showed a tendency but not a significant difference as far as the reaction of the calf muscles was concerned. Contraction of the forearm muscles, however, occurred significantly more often in the experimental group. The subjects executed these reactions without being aware of it.     

Effects of false increasing,decreasing, and true electromyographic biofeedback on the frequency of stuttering

Adult stutterers received auditory feedback of laryngeal area muscle activity while reading aloud under three conditions: (1) False Increasing Feedback, (2) False Decreasing Feedback, and (3) True Feedback. The subjects were unaware that the feedback in two conditions was being altered and were instructed not to manipulate the feedback signal. Decreases in the frequency of stuttering were observed for both the false increase and true feedback conditions. Factors contributing to the effectiveness of biofeedback techniques with stutterers are discussed.     

Operant conditioning of a small-scale muscle response

Six naive male subjects were reinforced for responses in the 20-30 microvolt range, and two each for those in 10-20 and 30-40 microvolt ranges. Records were taken of 15 min of "settling down," 15 min of initial operant level responding, 30 min of conditioning, and 45 min of extinction, 30 min with light present and 15 min without. The results were: (1) small-scale muscle potentials from the thenar eminence, in the 10-20, 20-30, and 30-40 microvolt ranges, were conditioned, using pointer movement as the reinforcement; (2) the response rate in adjacent ranges of greater and lesser amplitude also increased during such conditioning and decreased during the subsequent extinction; (3) during conditioning the frequency of response distribution shifted toward the reinforced range; (4) subjects were unaware of the reinforced response; (5) observing a noncontingent moving pointer increased the response rate in the 20-30 microvolt range, but did not lead to conditioning.     

One-trial learning and superior resistance to extinction of autonomic responses conditioned to potentially phobic stimuli.

Human subjects were exposed to pictures of potentially phobic (snakes) and supposedly neutral (houses) objects as conditioned stimuli (CSs) in a Pavlovian conditioning experiment with shock as unconditioned stimulus (US), and skin conductance and finger pulse volume as dependent variables. The skin conductance responses conditioned to phobic stimuli were acquired after one CS-US pairing, and showed practically no extinction, whereas the responses to neutral stimuli showed very little resistance to extinction after both 1 and 5 reinforcements. The superior resistance to extinction of the phobic condition was interpreted to be a specific associative effect. In general, the skin conductance acquisition data showed tendencies similar to those during extinction. For finger pulse volume responses, however, there were very weak conditioning effects, and no effect of stimulus.     

Operant behavior and the galvanic skin potential under DRL schedule

Motor and galvanic skin potential (GSP) activity were investigated during the conditioning, extinction, and reconditioning of motor responses under a differential reinforcement of low rate (DRL) schedule of reinforcement. Interresponse time (IRT) distributions for motor responses during conditioning and reconditioning gradually stabilized at a peak just beyond the minimal IRT required for reinforcement. Few unreinforced motor responses and "bursts" of motor responses were observed during conditioning and reconditioning. Relative to conditioning and reconditioning, extinction effected larger IRTs and smaller GSP amplitudes. GSP amplitudes were greater for unreinforced than for reinforced motor responses during conditioning and reconditioning. However, GSP amplitudes associated with the unreinforced extinction responses were smaller than either the reinforced or unreinforced responses during conditioning and reconditioning.     

The effect of CS-US contingency variation on GSR and on subjective CS-US relational awareness

Ninety subjects were tested in a single-cue Pavlovian conditioning paradigm involving three groups which differed with regard to the contingency relationship between CS and US (negative contingency, zero contingency, positive contingency). To examine the relationship between conditioned GSR performance and subject’s cognitive beliefs regarding the CS-US relationship, both GSR and CS-US relational learning were constantly measured on a continuous scale over the entire experimental session. The data suggest the independence of autonomic and cognitive responding in the single-cue Pavlovian paradigm.