Very brief exposure II: the effects of unreportable stimuli on reducing phobic behavior

This experiment compared the effects of exposure to masked phobic stimuli at a very brief stimulus-onset asynchrony on spider-phobic and non-phobic individuals. Participants were identified through a widely used questionnaire and a Behavioral Avoidance Test (BAT) with a live, caged tarantula to establish baseline levels of avoidance. One week later, they were individually administered one of two continuous series of masked images: spiders or flowers. Preliminary masking experiments showed that independent samples of participants from the same populations failed to recognize these stimuli. Participants in the main experiment reported ratings of subjective distress immediately before and after the exposure manipulation. Then they engaged in the BAT once again. Very brief exposure to images of spiders reduced phobic participants' avoidance of the tarantula. No effects were evidenced on subjective distress, or on non-phobic participants. Theoretical implications for the non-conscious basis of fear are discussed.     

What you cannot see can help you: the effect of exposure to unreportable stimuli on approach behavior

We examined effects of exposure to unreportable images of spiders on approach towards a tarantula. Pretests revealed awareness of the stimuli was at chance. Participants high or low (top and bottom 15%) on fear of spiders were randomly assigned to receive computer-generated exposure to unreportable pictures of spiders or outdoor scenes. They then engaged in a Behavioral Approach Task (BAT) with a live tarantula. Non-fearful participants completed more BAT items than spider-fearful individuals. Additionally, as predicted, a significant interaction (F(1,48)=5.12, p<.03) between fear of spiders and stimulus demonstrated that spider-fearful participants exposed to spiders completed more BAT items than spider-fearful participants exposed to control stimuli (but not as many as non-fearful participants). The findings support the hypothesis that exposure to unreportable feared stimuli promotes approach towards the feared object. Future research and clinical implications were discussed.     

Inhibition of fear acquisition in toddlers following positive modelling by their mothers

The present study used an experimental design to investigate the role of modelling as a protective factor in fear and avoidance learning in a sample of 77 toddlers. Mothers and their 12-20-month-old children were randomly assigned to one of three pre-exposure conditions: (1) a modelling group (n=27) observed their mothers responding positively to a fear-relevant stimulus; (2) a stimulus-only group (n=25) were exposed to a fear-relevant stimulus alone; and (3) a control group (n=25) were exposed to neither modelling nor the stimulus alone. Children in all three groups were then subjected to an observational conditioning trial in which the experimenter reacted with fear and disgust toward the stimulus. When subsequently tested for the acquisition of fear, children in the modelling group showed more positive affective reactions and more approach behaviours than either controls or children exposed to the stimulus alone. The results demonstrate that very young children can rapidly form lasting associations between maternal affective reactions and novel, fear-relevant stimuli. Further, positive maternal reactions to a stimulus can over-ride any fear-evoking effect of negative reactions to that stimulus by a stranger.     

The effects of safety-seeking behavior and guided threat reappraisal on fear reduction during exposure: an experimental investigation

We examined the effects of safety-seeking behavior and guided threat focus and reappraisal on fear reduction during exposure. Participants (N=46) displaying marked claustrophobic fear were randomized to one of three 30-min exposure conditions: (a) guided threat focus and reappraisal; (b) safety-behavior utilization; or (c) exposure only control. Tripartite outcome assessments during a behavioral approach test, along with measures of suffocation and restriction fears were obtained at pre- and post-treatment, and at a 2-week follow-up. Treatment process measures were collected throughout treatment and consisted of indices of fear activation; within and between-trial fear habituation; and suffocation and entrapment expectancies. Measures of safety behavior utilization and attentional focus were also collected to assess the integrity of the experimental manipulations. Consistent with prediction, those encouraged to utilize safety-behaviors during exposure showed significantly more fear at post-treatment and follow-up relative to those encouraged to focus and reevaluate their core threat(s) during exposure. Moreover, growth curve analyses of treatment process data analyses revealed that safety-behavior utilization exerted a detrimental effect on between-trial habituation; whereas guided threat reappraisal enhanced between-trial habituation.     

The divergent effects of fear and disgust on unconscious inhibitory control

Previous studies have shown that negative emotional distracters impair conscious inhibitory control. Recent research has shown that inhibitory control can be triggered unconsciously; therefore, in Experiment 1, we aimed to investigate whether negative emotional distracters affect unconscious inhibitory control. Furthermore, in Experiment 2, we examined whether fearful and disgusting distracters have differential effects on unconscious inhibitory control. Participants were instructed to perform a masked Go/No-Go task superimposed on a negative or neutral image cue (Experiment 1) or on a fearful, disgusting or neutral image cue (Experiment 2). Results showed that negative emotional distracters impaired unconscious inhibitory control; furthermore, disgusting distracters impeded unconscious inhibitory control when compared to fearful ones. This study is the first to provide evidence that fear and disgust may affect unconscious inhibitory control differently. These results expand the understanding of the relationship between emotions and inhibitory control.     

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.     

Verbal, behavioural and physiological assessment of the generalization of exposure-based fear reduction in a spider-anxious population

Clinical fear of spiders was assessed in 39 patients before and after exposure treatment and at a 3-month follow-up. The assessment included behavioral, physiological and self-report measures. Some patients were tested in the treatment context (group Same), while others were tested in a different context (group Different). Both groups demonstrated a significant fear reduction from pre- to post-treatment in all measures, which persisted at the 3-month follow-up. Contrary to our expectations, no clear difference was observed between the groups at any moment. However, a 1-year follow-up test of the self-report measure revealed a return of fear in group Same, but not in group Different. These results show (1) that the effects of exposure treatment persisted over contexts and time in the short term, and (2) that conducting treatment and tests in different contexts enhanced efficiency of exposure treatment in the long term.     

Post-extinction conditional stimulus valence predicts reinstatement fear: Relevance for long-term outcomes of exposure therapy

Exposure therapy for anxiety disorders is translated from fear conditioning and extinction. While exposure therapy is effective in treating anxiety, fear sometimes returns after exposure. One pathway for return of fear is reinstatement: unsignaled unconditional stimuli following completion of extinction. The present study investigated the extent to which valence of the conditional stimulus (CS+) after extinction predicts return of CS+ fear after reinstatement. Participants (N = 84) engaged in a differential fear conditioning paradigm and were randomised to reinstatement or non-reinstatement. We hypothesised that more negative post-extinction CS+ valence would predict higher CS+ fear after reinstatement relative to non-reinstatement and relative to extinction retest. Results supported the hypotheses and suggest that strategies designed to decrease negative valence of the CS+ may reduce the return of fear via reinstatement following exposure therapy.     

Emotional responses in spider fear are closely related to picture awareness

Theories of emotion propose that responses to emotional pictures can occur independently of whether or not people are aware of the picture content. Because evidence from dissociation paradigms is inconclusive, we manipulated picture awareness gradually and studied whether emotional responses varied with degree of awareness. Spider fearful and non-fearful participants viewed pictures of spiders and flowers at four levels of backward masking while electrodermal activity and heart rate were measured continuously. Recognition ratings confirmed that participants’ picture awareness decreased with masking. Critically, effects of spider fear on emotion ratings and heart rate also decreased with masking. These findings suggest that effects of spider fear on emotion ratings and heart rate are closely related to picture awareness.     

Unconscious semantic priming in the absence of partial awareness

In a recent paper in Psychological Science, Kouider and Dupoux reported obtaining unconscious Stroop priming only when subjects had partial awareness of the masked distractor words (i.e., could consciously perceive subword features that enabled reconstruction of whole words). Kouider and Dupoux conjectured that semantic priming occurs only when such partial awareness is present. The present experiments tested this conjecture in an affective categorization priming task that differed from Kouider and Dupoux’s in using masked distractors that subjects had practiced earlier as visible words. Experiment 1 showed priming from practiced words when subjects had no partial awareness of those words. Experiment 2 showed that, in the absence of partial awareness, practiced words yielded priming but not-practiced words did not. Experiment 3 corroborated Experiment 1 and 2s results using a different test of partial awareness. These results suggest that unconscious processing (rather than partial awareness) of subword elements drives masked semantic priming by practiced words.     

The fear of the body in psychotherapy

This paper identifies the fear of attending to and engaging with the patient's body and the therapist's body, regardless of therapeutic orientation, as a topic rarely explored in books and articles but pervasively experienced because of the cultural norms brought to the consulting room. It explores how we might name the constituent parts of this fear and describes how they inter-link. A case study then exemplifies learning about and transforming such fear in both patient and therapist. Finally, the paper offers suggestions of how therapists might increase their awareness and turn this fear into a tool which extends their range of skills.     

Fear and disgust processing during repeated exposure to threat-relevant stimuli in spider phobia

Although disgust plays a significant role in the etiology of spider phobia, there remains a paucity of research examining the role of disgust in the treatment of spider phobia. Spider fearful participants (N = 46) were randomly assigned to a disgust (view vomit images) or neutral activation (view inanimate objects) condition. They were then repeatedly exposed to a videotaped tarantula, during which time their fear, disgust, and physiological levels were assessed repeatedly. Growth curve analyses indicated that repeated exposure led to significant declines in fear and disgust with no statistically significant differences between the two conditions. However, there was marginal evidence for decreased physiological arousal during repeated exposure among spider fearful participants in the disgust activation condition compared to those in the neutral condition. Reduction in disgust during exposure in the disgust activation condition remained significant after controlling for change in fear, whereas change in fear was no longer significant after controlling for change in disgust. However, the opposite pattern of relations between change in fear and disgust was observed in the neutral activation condition. Higher fear and disgust activation during exposure was also associated with higher fear and disgust responding on a subsequent behavioral task and higher spider fear and disgust at 3-month follow-up. Baseline trait disgust propensity also predicted fear and disgust parameters during repeated exposure. The implications of these findings for the role of disgust in the treatment of spider phobia are discussed.     

Masked blindsight in normal observers: Measuring subjective and objective responses to two features of each stimulus

Recent visual masking studies that have measured visual awareness with graded subjective scales have often failed the show any evidence for unconscious visual processing in normal observers in a paradigm similar to that used in studies on blindsight patients. Without any reported awareness of the target, normal observers typically cannot discriminate target’s features better than chance. The present study examined processing of color and orientation by measuring graded awareness and forced-choice discriminations for both features in each trial. When no awareness for either feature was reported, discrimination of each feature succeed better than expected by chance, even when the other feature was incorrectly discriminated in the same trial. However, the characteristics of the mask determined whether or not masked blindsight was observed. We conclude that when the processing channels are free from intra-channel interference, unbound or weakly bound features can guide behaviour without any reported awareness in normal observers.     

Attention to phobic stimuli during exposure: the effect of distraction on anxiety reduction, self-efficacy and perceived control

To replicate and extend the finding that distraction facilitates between session anxiety reduction (), 27 spider phobics underwent three 10-min sessions of in vivo exposure followed by one 10-min exposure session at a 4-week follow-up, while having either stimulus-relevant focused conversation or stimulus-irrelevant distracting conversation with the experimenter. Physiological arousal and subjective anxiety were measured during exposure, and self-efficacy, perceived control and performance on a behavioural task were measured at pre-treatment, post session-3, and follow-up. Monitoring and blunting coping styles were also measured at pre-treatment to assess their impact on treatment outcome. Despite equal physiological activation between the groups, those who underwent distracted exposure showed greater reductions in subjective fear within and between sessions, and showed greater increases in self-efficacy ratings, internal perceived control and performance on a behavioural task. Coping style did not interact with the effect of distraction or focusing during exposure, however blunters had less subjective anxiety reduction overall, particularly when they underwent focused exposure. Results are discussed in terms of the emotional processing model and self-efficacy theory.     

Noradrenergic enhancement of associative fear memory in humans

Ample evidence in animals and humans supports the noradrenergic modulation in the formation of emotional memory. However, in humans the effects of stress on emotional memory are traditionally investigated by declarative memory tests (e.g., recall, recognition) for non-associative emotional stimuli (e.g., stories, pictures). Given that anxiety disorders are thought to originate from associative learning processes and are characterized by distressing emotional responses, the existing literature seems to be inconclusive for the understanding of these disorders. Here, we tested whether noradrenaline strengthens the emotional expression of associative fear memory by using a differential fear conditioning procedure in humans. Stimulation of the noradrenergic system by the administration of yohimbine HCl (20 mg) during memory formation did not directly augment the differential startle fear response 48 h later. Yet, the other retention tests uncovered that the administration of yohimbine HCl contrary to placebo pill extensively delayed the process of extinction learning and generated a superior recovery of fear (i.e., reinstatement and reacquisition). Conversely, the yohimbine HCl manipulation did not affect the skin conductance responding and the US expectancy ratings, emphasizing the concept of multiple memory systems. To our knowledge this is the first demonstration in humans that increased noradrenaline release during or shortly after a stressful event strengthens the formation of associative fear memory traces. The present findings suggest that noradrenaline may play an important role in the etiology and maintenance of anxiety disorders.     

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.     

A randomized controlled trial of the effect of D-cycloserine on extinction and fear conditioning in humans

Previous research has shown that D-cycloserine (DCS) facilitates extinction of Pavlovian fear conditioning in rats and enhances exposure therapy in humans. The aim of this study was to test the effect of DCS on extinction of fear conditioning in humans. In three experiments, 238 participants were given either DCS (50 or 500 mg) or placebo 2-3 h before extinction training following a differential shock conditioning paradigm. Clear extinction and recovery (return of fear) effects were observed on both skin conductance and self-reported shock expectancy measures in three studies. DCS had no influence on these effects. The same pattern was observed when the analysis was restricted to aware participants or to good conditioners, when fear-relevant cues (pictures of snakes) were used as the conditioned stimuli, or when analysis was restricted to heightened snake-fearful participants. These results suggest that DCS may not enhance the extinction, or prevent the recovery, of learned fear in a differential Pavlovian conditioning paradigm in humans. Further experimental research is needed to better understand the mechanisms underlying the therapeutic effects of DCS.