The effect of UCS inflation and deflation procedures on 'fear' conditioning

Davey (1992: Classical conditioning and the acquisition of human fears and phobias: a review and synthesis of the literature. Advances in Behaviour Research and Therapy, 14, 29-66) hypothesized that subjective revaluation of an unconditioned stimulus (UCS) would determine the strength of the autonomic conditioned response (CR) in the fear conditioning paradigm. The purpose of the present study was to examine the effect of UCS aversiveness on the CR strength in the fear conditioning paradigm. The UCS aversiveness was controlled by the UCS intensity; that is, the UCS intensity was increased for the inflation group or decreased for the deflation group. Thirty subjects were randomly assigned to the inflation or the deflation group, and they participated under both experimental and control conditions. All subjects went through the pretest, the acquisition of classical conditioning, the UCS intensity operation, and the test sessions. The indices of the CR were skin conductance responses (SCRs) and a subjective aversion to the conditioned stimulus (CS). The main results were as follows. (1) The CR strength measured by SCR was increased by the UCS inflation and decreased by the UCS deflation. (2) The subjective aversiveness of the CS was not sensitive to both manipulations of UCS intensity. These results suggested that the autonomic CR strength might be influenced by the subjective revaluation of UCS, as Davey (1992) described. The result from the test of the subjective aversiveness of the CS, however, could not support Davey's model. The difference between expressions of the SCR and the subjective aversiveness of the CS might be caused by different learning systems.     

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.     

The development of cued versus contextual conditioning in a predictable and an unpredictable human fear conditioning preparation

In this human fear conditioning study, the online development of conditioned US-expectancy to discrete cues and background contexts was measured in two groups. In the paired group (n=30), the CS was systematically followed by an aversive shock (US). In the unpaired group (n=30), CS and US were presented explicitly unpaired. Using US-expectancy ratings, we replicated the basic finding already illustrated in humans with startle modulation. In the paired group, the CS elicited more US-expectancy than the context, whereas in the unpaired group, the context elicited more US-expectancy than the CS. Interestingly, we also observed a trial-by-trial development of conditioning to the context in the unpaired group as indicated by a significant linear trend. This gradual development and the evidence for the role of US-expectancy in contextual fear add to the idea that cued and contextual fear rely on the same basic associative processes.     

The effects of alcohol consumption and expectancies in an experimental date rape analogue

This study examined the impact of perceived token resistance and the psychological and pharmacological effects of alcohol consumption on men's discrimination of when a female wants her partner to stop his sexual advances. In a 2 (alcohol vs. no alcohol) × 2 (expectancy vs. no expectancy) × 2 (perceived token resistance vs. no resistance) randomized factorial design, male college students were exposed to an audiotape of a date rape. Before listening, participants were told that on the previous date the woman did not resist sexual contact or that she initially objected to the contact but the man was able to obtain the level of intimacy he desired. Relative to participants assigned to the no-alcohol expectancy or no-alcohol consumption group, participants in the alcohol expectancy and alcohol consumption groups took significantly longer to determine that the man should refrain from attempting further sexual contact. The implications of the findings are discussed.This investigation was carried out by the first author under the supervision of the second author in partial fulfillment of the requirements for the degree of Doctor of Philosophy.     

The effects of postconditioning revaluation of CS1 and UCS following pavlovian second-order electrodermal conditioning in humans

An experiment is described which uses various inferential post-conditioning revaluation techniques in order to clarify the associative substructure underlying Pavlovian electrodermal conditioning in human subjects. This study established a second-order skin conductance response (SCR) by pairing a CS₁ with an aversive 115 dB tone (UCS), and then pairing a different stimulus (CS₂) with CS₁. The second-order SCR survived post-conditioning extinction of the response to CS₁, but was abolished when (i) a post-conditioning habituation procedure resulted in a favourable revaluation of the tone UCS, or (ii) when subjects were given instructions which informed them that there would be no more UCS presentations. These results suggest that in the second-order electrodermal conditioning paradigm described, CR₂ is not mediated by S-R links--as it appears to be in second-order aversive conditioning in nonhuman animals--but is affected by manipulations which modify the subject's cognitions concerning the UCS.     

The effects of distributed training on retention of operant conditioning in human infants

Long-term retention of operant footkicking acquired in the mobile conjugate reinforcement paradigm was assessed as a function of the distribution of training time. In the first study, 3-month-old infants were trained for either one 18-min session or for two 9-min or three 6-min sessions separated by 24-hr intervals. All infants exhibited retention during a test administered immediately after training, but only those trained in a single session continued to perform the conditioned response during cued-recall tests 7 or 14 days later. Infants trained in three sessions showed no evidence of remembering the contingency even after a week. A warm-up decrement, seen in the day-to-day performance of infants in the distributed conditions, was eliminated in the second study by the interpolation of a nonreinforcement period at the outset of daily sessions. This procedure also enhanced long-term retention such that infants trained in three 6-min session now remembered the contingency for 14 days and did not differ from infants who had received a single 18-min session. Whether distributed training facilitates or impairs long-term retention appears to depend on the opportunity for infants to acquire a sufficient number (or kind) of effective retrieval cues during original learning.     

Effects of UCS intensity and postpeak acquisition trials on classical conditioning of the SCR

The present study examined the effects of UCS intensity and number of postpeak acquisition trials on classical conditioning and extinction of the SCR. A 2 × 3 design was employed in which subjects received either a 1, 2, or 4 mA shock UCS and either two or 16 acquisition trials beyond the peak CR. While conditioning was demonstrated during acquisition, there was no relationship between strength of conditioning and intensity of UCS. The phenomenon of stronger resistance to extinction following fewer acquisition trials (e.g., two past the peak CR) than with many (e.g., 16 past the peak CR) was demonstrated only for the groups that were conditioned with the 4 mA UCS. Resistance to extinction varied positively with UCS intensity, but only for the subjects who received two postpeak acquisition trials. Sixteen trials beyond the peak CR resulted in the UCS intensity having little or no effect on resistance to extinction.     

The influence of psychoticism and extraversion on classical eyelid conditioning using a paraorbital shock UCS

An experiment is described in which the effects of Psychoticism and Extraversion on classical eyelid conditioning were examined using a balanced design involving two levels of paraorbital shock intensity and two levels of response threshold. Questionnaire measures of Anxiety and Impulsivity were also analysed together with subjective ratings of the UCS. Results were broadly consistent with Eysenck's personality theory in that subjects scoring high on Psychoticism demonstrated lower levels of conditioning.     

Classical conditioning and retention of the infant's eyelid response: effects of age and interstimulus interval

Independent groups of 10-,20-, and 30-day-old infants were subjected to a classical eyelid conditioning procedure involving either a 500- or a 1500-msec interstimulus interval (ISI). Ten days later, all received a second conditioning session. A reliable increase in conditioned responding was observed at all ages but only by infants receiving the 1500-msec ISI. Although age was not a significant factor in any conditioning measure except final performance level, which was greater for the oldest than for the youngest group, it did influence long-term retention. A reliable memory component was observed in the Session 2 performance of infants initially trained at 20 and 30 days but not at 10 days. These data demonstrate the importance of temporal parameters in the formation of conditioned associations very early in infancy and provide evidence for the long-term behavioral consequences of those associations.     

Remembering September 11th: the role of retention interval and rehearsal on flashbulb and event memory

Retention interval and rehearsal effects on flashbulb and event memory for 11th September 2001 (9/11) were examined. In Experiment 1, college students were assessed three times (Groups 1 and 2) or once (Group 3) over 11 weeks. In Experiment 2, three new groups assessed initially at 23 weeks (Group 4), 1 year (Group 5), or 2 years (Group 6) were compared at 1 year and at 2 years with subsamples of those assessed previously. No effects of retention interval length or rehearsal were found for flashbulb memory, which contained details at each assessment. Event memory, but not consistency, was detrimentally affected by long retention intervals, but improved with rehearsal. Recall was higher for the reception event than for the main events. Also, consistency from 1 day to 11 weeks, but not 1 year to 2 years, was higher for flashbulb memory than for event memory. Event recall was enhanced when respondents conceived of their memory as vivid, frozen, and encompassing a longer period of time. Positive correlations were found for event memory with confidence in accuracy and with rehearsal through discussion at 2 years.     

Effects of proactive interference and rehearsal on the primary and secondary components of short-term retention

Under the conditions of the distractor paradigm, short-term retention declines to a minimum in a very brief period. The rapid forgetting can be said to reflect the declining contribution of the short-term store or primary memory and the asymptote can be taken as a measure of the contribution of the long-term store or secondary memory. It was shown that manipulating proactive effects by varying the recency of prior material affected only the primary memory component of the short-term retention function. On the other hand manipulating the difficulty of the subsidiary task performed during the retention period with proactive effects held constant affected both the primary and the secondary components. The results were discussed with respect to the relation between the two memory components and the idea that proactive effects are limited to long-term store.     

The effects of safety behaviors on the fear of contamination: an experimental investigation

The strategies used by anxious individuals to prevent feared outcomes, known as safety behaviors, are thought to maintain pathological anxiety by preventing the disconfirmation of inaccurate threat beliefs. However, it is possible that safety behaviors might also contribute to the development and exacerbation of anxiety symptoms. The present study tested this notion in a sample of undergraduate participants with either low (n=30) or high (n=26) levels of contamination fear. After a week-long baseline period, participants spent 1 week engaging in a clinically representative array of contamination-related safety behaviors on a daily basis, followed by a second baseline period. Subsequent to the safety behavior manipulation, participants evidenced statistically significant increases in threat overestimation, contamination fear symptoms, and emotional and avoidant responses to three contamination-related behavioral avoidance tasks (BATs). In contrast, anxiety and depressive symptoms remained stable. The magnitude of change in contamination concerns was equivalent among participants in both contamination fear groups. Our findings suggest that contamination-related safety behaviors elicit a modest and specific increase in the fear of contamination. Possible mechanisms for this effect, as well as implications for the role of safety behaviors in the psychopathology of anxiety disorders, are discussed.     

The effects of safety behaviors on health anxiety: an experimental investigation

The present study examined the extent to which safety behaviors exacerbate symptoms of hypochondriasis (severe health anxiety). Participants were randomized into a safety behavior (n = 30) or control condition (n = 30). After a baseline period, participants in the safety behavior condition spent one week actively engaging in a clinically representative array of health-related safety behaviors on a daily basis, followed by a second week-long baseline period. Participants in the control condition monitored their normal use of safety behaviors. Compared to control participants, those in the safety behavior condition reported significantly greater increases in health anxiety, hypochondriacal beliefs, contamination fear, and avoidant responses to health-related behavioral tasks after the safety behavior manipulation. In contrast, general anxiety symptoms did not significantly differ between the two groups as a function of the manipulation. Mediational analyses were consistent with the hypothesis that changes in the frequency of health-related thoughts mediated the effects of the experimental manipulation on health anxiety. These findings suggest that safety behaviors are associated with increases in health anxiety, perhaps by fostering catastrophic thoughts about health. The implications of these findings for the conceptualization of hypochondriasis as an anxiety disorder are discussed.