Conceptual generalisation in fear conditioning using single and multiple category exemplars as conditional stimuli - electrodermal responses and valence evaluations generalise to the broader category

Conceptual generalisation occurs when conditional responses generalise to novel stimuli from the same category. Past research demonstrates that physiological fear responses generalise across categories, however, conceptual generalisation of stimulus valence evaluations during fear conditioning has not been examined. We investigated whether conceptual generalisation, as indexed by electrodermal responses and stimulus evaluations, would occur, and differ after training with single or multiple conditional stimuli (CSs). Stimuli from two of four categories (vegetables, farm animals, clothing, and office supplies) were used as the CS+ (followed by an electric stimulus) or CS- (presented alone). Generalisation was assessed by presenting novel stimuli from the CS categories after acquisition, extinction, and reinstatement. One category exemplar was used as the CS+ and CS- in the single group, whereas three exemplars were used as the CS+ and CS- in the multiple group. Electrodermal responses generalised in acquisition and extinction but did not differ between groups. In the multiple group, CS evaluations generalised in acquisition and extinction, whereas generalisation was not evident in the single group. Training with multiple CSs also resulted in the extinction of stimulus valence. The current findings have implications for future research examining the generalisation of valence and for exposure-based treatments of anxiety.

Imagery-enhanced v. verbally-based group cognitive behavior therapy for social anxiety disorder: a randomized clinical trial

BACKGROUND

Cognitive behavior therapy (CBT) is effective for most patients with a social anxiety disorder (SAD) but a substantial proportion fails to remit. Experimental and clinical research suggests that enhancing CBT using imagery-based techniques could improve outcomes. It was hypothesized that imagery-enhanced CBT (IE-CBT) would be superior to verbally-based CBT (VB-CBT) on pre-registered outcomes.

METHODS

A randomized controlled trial of IE-CBT v. VB-CBT for social anxiety was completed in a community mental health clinic setting. Participants were randomized to IE (n = 53) or VB (n = 54) CBT, with 1-month (primary end point) and 6-month follow-up assessments. Participants completed 12, 2-hour, weekly sessions of IE-CBT or VB-CBT plus 1-month follow-up.

RESULTS

Intention to treat analyses showed very large within-treatment effect sizes on the social interaction anxiety at all time points (ds = 2.09-2.62), with no between-treatment differences on this outcome or clinician-rated severity [1-month OR = 1.45 (0.45, 4.62), p = 0.53; 6-month OR = 1.31 (0.42, 4.08), p = 0.65], SAD remission (1-month: IE = 61.04%, VB = 55.09%, p = 0.59); 6-month: IE = 58.73%, VB = 61.89%, p = 0.77), or secondary outcomes. Three adverse events were noted (substance abuse, n = 1 in IE-CBT; temporary increase in suicide risk, n = 1 in each condition, with one being withdrawn at 1-month follow-up).

CONCLUSIONS

Group IE-CBT and VB-CBT were safe and there were no significant differences in outcomes. Both treatments were associated with very large within-group effect sizes and the majority of patients remitted following treatment.

Conditional stimulus choices affect fear learning: Comparing fear conditioning with neutral faces and shapes or angry faces

Past fear conditioning studies have used different types of conditional stimuli (CSs). Whether this choice affects learning outcomes in particular when neutral stimuli (e.g., neutral faces vs. shapes) are used is unclear. Data were aggregated across nine studies using an electric shock unconditional stimulus to test for differences in acquisition and extinction of electrodermal responses and self‐reported CS pleasantness when CSs were neutral faces or shapes (Experiment 1, N = 594) and when CSs were angry or neutral faces (Experiment 2, N = 157). Reliable electrodermal conditioning was observed in all stimulus conditions. We found stronger differential conditioning in electrodermal second interval responses and CS pleasantness and more pronounced extinction in CS pleasantness for neutral shape than neutral face CSs, but no differences in electrodermal first interval responses, the most frequently reported index of fear conditioning. For angry and neutral face CSs, there were no differences during acquisition, but the extinction of first and second interval electrodermal conditioning to angry faces was retarded relative to neutral faces. Acquisition of differential CS pleasantness, which was reliably observed for neutral face CSs, was absent for angry face CSs. The current results suggest that fear conditioning with a neutral face and shape CSs yields broadly similar results with differences limited to second interval electrodermal responses and CS pleasantness ratings. Using angry face CSs resulted in impaired extinction of electrodermal indices and no differential CS pleasantness ratings and should only be considered in studies designed to address questions about these specific CS materials.

Methodological choices like the nature of the conditional stimulus (CS) may affect fear learning. Here, we document in a very well powered analysis, that differences in fear conditioned to neutral face or shape CSs are limited to anticipatory electrodermal responses and self‐reported CS pleasantness but are not apparent in the more frequently reported electrodermal responses to CS onset. In contrast, differences in fear conditioned to angry and neutral face CSs emerge across indices of fear, in particular during extinction.

An investigation of implicit bias about bending and lifting

OBJECTIVES

Previous studies in a high-income country have demonstrated that people with and without low back pain (LBP) have an implicit bias that bending and lifting with a flexed lumbar spine is dangerous. These studies present two key limitations: use of a single group per study; people who recovered from back pain were not studied. Our aims were to evaluate: implicit biases between back posture and safety related to bending and lifting in people who are pain-free, have a history of LBP or have current LBP in a middle-income country, and to explore correlations between implicit and explicit measures within groups.

METHODS

Exploratory cross-sectional study including 174 participants (63 pain-free, 57 with history of LBP and 54 with current LBP). Implicit biases between back posture and safety related to bending and lifting were assessed with the Implicit Association Test (IAT). Participants completed paper-based (Bending Safety Belief [BSB]) and online questionnaires (Tampa Scale of Kinesiophobia; Back Pain Attitudes Questionnaire).

RESULTS

Participants displayed significant implicit bias between images of round-back bending and lifting and words representing "danger" (IATD-SCORE: Pain-free group: 0.56 (IQR=0.31-0.91; 95% CI [0.47, 0.68]); history of LBP group: 0.57 (IQR=0.34-0.84; 95% CI [0.47, 0.67]); current LBP group: 0.56 (IQR=0.24-0.80; 95% CI [0.39, 0.64])). Explicit measures revealed participants hold unhelpful beliefs about the back, perceiving round-back bending and lifting as dangerous (BSBthermometer: Pain-free group: 8 (IQR=7-10; 95% CI [7.5, 8.5]); history of LBP group: 8 (IQR=7-10; 95% CI [7.5, 9.0]); current LBP group: 8.5 (IQR=6.75-10; [7.5, 9.0])). There was no correlation between implicit and explicit measures within the groups.

CONCLUSIONS

In a middle-income country, people with and without LBP, and those who recovered from LBP have an implicit bias that round-back bending and lifting is dangerous.

Featural vs. Holistic processing and visual sampling in the influence of social category cues on emotion recognition

Past research demonstrates that emotion recognition is influenced by social category cues present on faces. However, little research has investigated whether holistic processing is required to observe these influences of social category information on emotion perception, and no studies have investigated whether different visual sampling strategies (i.e. differences in the allocation of attention to different regions of the face) contribute to the interaction between social cues and emotional expressions. The current study aimed to address this. Participants categorised happy and angry expressions on own- and other-race faces, and male and female faces. In Experiments 1 and 2, holistic processing was disrupted by presenting inverted faces (Experiment 1) or part faces (Experiment 2). In Experiments 3 and 4 participants' eye-gaze to eye and mouth regions was also tracked. Disrupting holistic processing did not alter the moderating influence of sex and race cues on emotion recognition (Experiments 1, 2, 4). Gaze patterns differed as a function of emotional expression, and social category cues, however, eye-gaze patterns did not reflect response time patterns (Experiments 3 and 4). Results indicate that the interaction between social category cues and emotion does not require holistic processing and is not driven by differences in visual sampling.

Engagement of the contralateral limb can enhance the facilitation of motor output by loud acoustic stimuli

When intense sound is presented during light muscle contraction, inhibition of the corticomotoneuronal pathway is observed. During action preparation, this effect is reversed, with sound resulting in excitation of the corticomotoneuronal pathway. We investigated how combined maintenance of a muscle contraction during preparation for a ballistic action impacts the magnitude of the facilitation of motor output by a loud acoustic stimulus (LAS) - a phenomenon known as the StartReact effect. Participants executed ballistic wrist flexion movements and a LAS was presented simultaneously with the imperative signal in a subset of trials. We examined whether the force level or muscle used to maintain a contraction during preparation for the ballistic response impacted reaction time and/or the force of movements triggered by the LAS. These contractions were sustained either ipsilaterally or contralaterally to the ballistic response. The magnitude of facilitation by the LAS was greatest when low force flexion contractions were maintained in the limb contralateral to the ballistic response during preparation. There was little change in facilitation when contractions recruited the contralateral extensor muscle, or when they were sustained in the same limb that executed the ballistic response. We conclude that a larger network of neurons which may be engaged by a contralateral sustained contraction prior to initiation may be recruited by the LAS, further contributing to the motor output of the response. These findings may be particularly applicable in stroke rehabilitation where engagement of the contralesional side may increase the benefits of a LAS to the functional recovery of movement.

Neural prediction errors depend on how an expectation was formed

When a visual event is unexpected, because it violates a train of repeated events, it excites a greater positive electrical potential at sensors positioned above occipital-parietal human brain regions (the P300). Such events can also seem to have an increased duration relative to repeated (implicitly expected) events. However, recent behavioural evidence suggests that when events are unexpected because they violate a declared prediction-a guess-there is an opposite impact on duration perception. The neural consequences of incorrect declared predictions have not been examined. We replicated the finding whereby repetition violating events elicit a larger P300 response. However, we found that events that violated a declared prediction entrained an opposite pattern of response-a smaller P300. These data suggest that the neural consequences of a violated prediction are not uniform but depend on how the prediction was formed.

The absence of differential electrodermal responding in the second half of acquisition does not indicate the absence of fear learning

Many contemporary studies of human fear conditioning exclude participants who fail to show differential electrodermal responding during late stages of acquisition training, deeming them to be non-Learners. The current study examined whether non-Learners, defined as those who fail to show larger electrodermal first interval responses to CS+ than to CS- in the second half of acquisition, show differential electrodermal responding early during acquisition or during extinction or evidence of fear-learning on other measures, including rated CS valence and contingency report. In a sample of 351 participants who completed a standard differential fear-conditioning paradigm that employed electrodermal first and second interval responses (FIR, SIR), continuous CS evaluations, and post-experimental contingency reports to assess fear-learning, 74 participants were identified as non-Learners. These non-Learners displayed overall smaller electrodermal responses but showed evidence for differential conditioning during acquisition in electrodermal FIR (block1) and SIR (blocks 2-3) and in CS evaluations during acquisition (blocks 2-4) and extinction (blocks 1-4). Fifty-nine non-Learners correctly reported the contingencies. A lack of differential electrodermal first interval responding during the second half of acquisition does not indicate the absence of fear-learning. Rather, this criterion appears to capture participants who exhibit low physiological arousal and performance decrements toward the end of acquisition. Applying criteria based on "end of acquisition" electrodermal responding to determine "non-learning" results in the exclusion of participants who display fear-learning at other experimental stages or in other measures.

Premovement inhibition can protect motor actions from interference by response-irrelevant sensory stimulation

KEY POINTS

Suppression of corticospinal excitability is reliably observed during preparation for a range of motor actions, leading to the belief that this preparatory inhibition is a physiologically obligatory component of motor preparation. The neurophysiological function of this suppression is uncertain. We restricted the time available for participants to engage in preparation and found no evidence for preparatory inhibition. The function of preparatory inhibition can be inferred from our findings that sensory stimulation can disrupt motor output in the absence of preparatory inhibition, but enhance motor output when inhibition is present. These findings suggest preparatory inhibition may be a strategic process which acts to protect prepared actions from external interference. Our findings have significant theoretical implications for preparatory processes. Findings may also have a pragmatic benefit in that acoustic stimulation could be used therapeutically to facilitate movement, but only if the action can be prepared well in advance.

ABSTRACT

Shortly before movement initiation, the corticospinal system undergoes a transient suppression. This phenomenon has been observed across a range of motor tasks, suggesting that it may be an obligatory component of movement preparation. We probed whether this was also the case when the urgency to perform a motor action was high, in a situation where little time was available to engage in preparatory processes. We controlled the urgency of an impending motor action by increasing or decreasing the foreperiod duration in an anticipatory timing task. Transcranial magnetic stimulation (TMS; experiment 1) or a loud acoustic stimulus (LAS; experiment 2) were used to examine how corticospinal and subcortical excitability were modulated during motor preparation. Preparatory inhibition of the corticospinal tract was absent when movement urgency was high, though motor actions were initiated on time. In contrast, subcortical circuits were progressively inhibited as the time to prepare increased. Interestingly, movement force and vigour were reduced by both TMS and the LAS when movement urgency was high, and enhanced when movement urgency was low. These findings indicate that preparatory inhibition may not be an obligatory component of motor preparation. The behavioural effects we observed in the absence of preparatory inhibition were induced by both TMS and the LAS, suggesting that accessory sensory stimulation may disrupt motor output when such stimulation is presented in the absence of preparatory inhibition. We conclude that preparatory inhibition may be an adaptive strategy which can serve to protect the prepared motor action from external interference.

Presentation of unpaired unconditional stimuli during extinction reduces renewal of conditional fear and slows re-acquisition

Past research has shown that presenting unconditional stimuli (US) during extinction training, either paired with the conditional stimulus (CS) or explicitly unpaired, can reduce spontaneous recovery and slow the re-acquisition of conditional fear. Whether contextual renewal of conditioned fear as indexed by electrodermal responses and self-report measures of anxiety and CS evaluations is also reduced after presentation of paired or unpaired USs during extinction training is currently unclear. Three groups of participants (Paired, Unpaired, Standard Extinction) completed a sequence of habituation, acquisition, extinction, renewal, and re-acquisition phases. During extinction, five CS-US pairings were presented in group Paired, whereas five US were presented alone in group Unpaired. No US were presented during standard extinction. For all groups, extinction was conducted in a context that was different from that of the other phases. Extinction of differential electrodermal responding was evident in groups Unpaired and Standard, but not in group Paired. Contextual renewal and fast re-acquisition, as indexed by differential electrodermal responding, were evident in group Standard, but not in group Unpaired and differential electrodermal responding persisted in group Paired. After extinction, self-reported anxiety was higher in groups Paired and Unpaired, but differential CS evaluations were evident in group Paired only. The current results suggest that presenting additional unpaired USs during extinction training strengthens extinction and protects against the renewal of differential electrodermal responding.

The effects of presenting additional stimuli resembling the CS+ during extinction on extinction retention and generalisation to novel stimuli

Recent studies have shown that extinction training including the conditional stimulus (CS+) and stimuli similar to the CS + enhances extinction retention and generalisation to novel stimuli. The aim of the present study was to confirm that these effects are specific to presenting stimuli similar to the CS+ during extinction and not merely an effect of additional trials or additional stimuli unrelated to the CS+. In an experiment conducted in a single session on the same day, participants (134 adults; 70.7% female; 17-40 years of age, M = 20.04, SD = 4.36) completed a habituation phase followed by an acquisition phase using dog images presented with (CS+) and without (CS-) a dog growl paired with a scream unconditional stimulus (US). Participants were randomly allocated to four extinction conditions: Multiple exemplar extinction comprising the CSs and two novel dog images similar to the CS+; Standard extinction control matched for the number of CS+ and CS- presentations; Extended extinction control matched for the total number extinction trials, and Other stimuli extinction control comprising the CSs and two novel stimuli unrelated to the CS+. All participants completed an extinction test with the original CSs followed by a generalisation test with two novel dog images. Multiple, Standard and Other stimuli extinction groups exhibited larger skin conductance responses (SCRs) during extinction to the CSs compared to the Extended extinction group. SCRs to the additional dog images in the Multiple group were larger than SCRs to the additional CSs in the Extended group and the novel images in the Other stimuli group. There were no group differences in responses to the CSs during extinction test. Unlike the other groups, SCRs to the first presentation of the novel generalisation dogs did not differ from those to the last CS trials in extinction in the Multiple group. However, this group difference did not persist beyond the initial generalisation trial. Finally, the Multiple, Extended, and Other stimuli groups exhibited more negative CS evaluations after extinction, extinction test, and generalisation test than the Standard extinction group. The results suggest that extinction with the original CSs and additional stimuli resembling the CS + elevated physiological responses during extinction and reduced physiological responses to novel stimuli similar to the CSs. Further studies are needed including clinical samples and trial-by-trial evaluations of the stimuli presented.

Preparatory suppression and facilitation of voluntary and involuntary responses to loud acoustic stimuli in an anticipatory timing task

In this study, we sought to characterize the effects of intense sensory stimulation on voluntary and involuntary behaviors at different stages of preparation for an anticipated action. We presented unexpected loud acoustic stimuli (LAS) at-rest and at three critical times during active movement preparation (-1,192, -392, and 0 ms relative to expected voluntary movement onset) to probe the state of the nervous system, and measured their effect on voluntary and involuntary motor actions (finger-press and eye-blink startle reflex, respectively). Voluntary responses were facilitated by LAS presented during active preparation, leading to earlier and more forceful responses compared to control and LAS at-rest. Notably, voluntary responses were significantly facilitated on trials where the LAS was presented early during preparation (-1,192 ms). Eye-blink reflexes to the LAS at -392 ms were significantly reduced and delayed compared to blinks elicited at other time-points, indicating suppression of sub-cortical excitability. However, voluntary responses on these trials were still facilitated by the LAS. The results provide insight into the mechanisms involved in preparing anticipatory actions. Induced activation can persist in the nervous system and can modulate subsequent actions for a longer time-period than previously thought, highlighting that movement preparation is a continuously evolving process that is susceptible to external influence throughout the preparation period. Suppression of sub-cortical excitability shortly before movement onset is consistent with previous work showing corticospinal suppression which may be a necessary step before the execution of any voluntary response.

Stable middle-aged face recognition: No moderation of the own-age bias across contexts

The own-age bias (OAB) has been proposed to be caused by perceptual expertise and/or social-cognitive mechanisms. Investigations into the role of social cognition have, however, yielded mixed results. One reason for this might be the tendency for research to focus on the OAB in young adults, between young and older adult faces where other-age individuation experience is low. To explore whether social-cognitive manipulations may be successful when observers have sufficient other-age individuation experience, we examined biases involving middle-aged other-age faces and the influence of a context manipulation. Across four experiments, young adult participants were presented with middle-aged faces alongside young or older adult faces to remember. We predicted that in contexts where middle-aged faces were positioned as other-age faces (alongside young adult faces), recognition performance would be worse than when they were positioned as relative own-age faces (alongside older adult faces). However, the context manipulations did not moderate middle age face recognition. This suggests that past findings that context does not change other-age face recognition holds for other-age faces for which observers have higher individuation experience. These findings are consistent with a perceptual expertise account of the OAB but more investigation of the generality of these results is required.

Cumulative distribution functions: An alternative approach to examine the triggering of prepared motor actions in the StartReact effect

There has been much debate concerning whether startling sensory stimuli can activate a fast-neural pathway for movement triggering (StartReact) which is different from that of voluntary movements. Activity in sternocleidomastoid (SCM) electromyogram is suggested to indicate activation of this pathway. We evaluated whether SCM activity can accurately identify trials which may differ in their neurophysiological triggering and assessed the use of cumulative distribution functions (CDFs) of reaction time (RT) data to identify trials with the shortest RTs for analysis. Using recent data sets from the StartReact literature, we examined the relationship between RT and SCM activity. We categorised data into short/longer RT bins using CDFs and used linear mixed-effects models to compare potential conclusions that can be drawn when categorising data on the basis of RT versus on the basis of SCM activity. The capacity of SCM to predict RT is task-specific, making it an unreliable indicator of distinct neurophysiological mechanisms. Classification of trials using CDFs is capable of capturing potential task- or muscle-related differences in triggering whilst avoiding the pitfalls of the traditional SCM activity-based classification method. We conclude that SCM activity is not always evident on trials that show the early triggering of movements seen in the StartReact phenomenon. We further propose that a more comprehensive analysis of data may be achieved through the inclusion of CDF analyses. These findings have implications for future research investigating movement triggering as well as for potential therapeutic applications of StartReact.

The effect of social anxiety on top-down attentional orienting to emotional faces

One of the fundamental factors maintaining social anxiety is biased attention toward threatening facial expressions. Typically, this bias has been conceptualized as driven by an overactive bottom-up attentional system; however, this potentially overlooks the role of top-down attention in being able to modulate this bottom-up bias. Here, the role of top-down mechanisms in directing attention toward emotional faces was assessed with a modified dot-probe task, in which participants were given a top-down cue ("happy" or "angry") to attend to a happy or angry face on each trial, and the cued face was either presented with a face of the other emotion (angry, happy) or a neutral face. This study found that social anxiety was not associated with differences in shifting attention toward cued angry faces. However, participants with higher levels of social anxiety were selectively impaired in attentional shifting toward a cued happy face when it was paired with an angry face, but not when paired with a neutral face. The results indicate that top-down attention can be used to orient attention to emotional faces, but that higher levels of social anxiety are associated with selective deficits in top-down control of attention in the presence of threat. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Measuring unconditional stimulus expectancy during evaluative conditioning strengthens explicit conditional stimulus valence

During evaluative conditioning, a neutral conditional stimulus (CS) becomes pleasant or unpleasant after pairings with a positive/negative unconditional stimulus (US). Measures of US expectancy are commonly assessed during conditioning but it is unclear whether this affects evaluative learning. In Experiment 1, we examined whether the concurrent assessment of US expectancy alongside measures of CS valence would influence the acquisition, extinction, and reinstatement of explicit CS valence. Participants rated both valence and expectancy during conditioning (valence/expectancy group) or only CS valence (valence only group). Evaluative conditioning was acquired in both groups during acquisition, but its magnitude was enhanced in the valence/expectancy group. Measuring US expectancy did not influence the extinction or reinstatement of conditional valence. In Experiment 2, we confirmed the enhancement of evaluative conditioning due to concurrent measurement of US expectancy in an explicit measure, but did not find corresponding evidence in an implicit measure of conditional valence. In Experiment 3, we replicated the results using a different US expectancy scale and demonstrated that measuring CS valence multiple times throughout conditioning also strengthens conditional valence. Overall, the results suggest that the measurement of US expectancy and CS valence throughout conditioning draws attention to the contingencies and strengthens explicit evaluative learning.

Motor output matters: Evidence of a continuous relationship between Stop/No-go P300 amplitude and peak force on failed inhibitions at the trial-level

Motor actions can be suppressed with varying degrees of success, but this variability is not often captured as responses are typically represented as binary (response vs. no-response). Although the Stop/No-go P300 has been implicated as an index of inhibitory-control, it is unclear how the range of motor outputs relates to the P300. We examined the nature of this association in two experiments using an Anticipatory Timing and a Go/No-go Task, while measuring peak force, movement onset time, and P300. In both experiments, our results showed that trial-by-trial P300 amplitude on Failed Inhibitions were continuously related to peak force, where higher force (reflecting a greater degree of error) was associated with smaller P300 amplitude. Compared to Successful Inhibitions, P300 amplitude and onset latency on Failed Inhibitions were significantly reduced and delayed. Although the binary categorization of inhibition-success (Successful vs. Failed) accounts for significant variance in the P300, it misses a reliable linear relationship that can be captured by continuous measures of motor output. Overall, the results provide evidence that P300 may reflect the continuously varying engagement of inhibitory-control. We present an activation model to visualize the P300-force association and to illustrate how motor output might be modeled in the context of inhibitory-control. Our results highlight the relevance of P300 amplitude and the importance of studying the spectrum of motor output and the need for future models to account for motor output.

"Prepared" fear or socio-cultural learning? Fear conditioned to guns, snakes, and spiders is eliminated by instructed extinction in a within-participant differential fear conditioning paradigm

Across three experiments, we investigated whether electrodermal responses conditioned to ontogenetic fear-relevant (pointed guns) and phylogenetic fear-relevant stimuli (snakes and spiders) would resist instructed extinction in a within-participant differential fear conditioning paradigm. Instructed extinction involves informing participants before extinction that the unconditional stimulus (US) will no longer be presented. This manipulation has been shown to abolish fear conditioned to fear-irrelevant conditional stimuli, but is said to leave fear conditioned to images of snakes and spiders intact. The latter finding, however, has only been demonstrated when fear-relevance is manipulated between-groups. It is also not known whether instructed extinction affects fear conditioned to ontogenetic fear-relevant stimuli, such as pointed guns. In Experiment 1, we demonstrated that fear conditioned to images of pointed guns does not resist instructed extinction. In Experiment 2, we detected some evidence to suggest that fear conditioned to images of snakes and spiders survives instructed extinction but this evidence was not conclusive. In Experiment 3, we directly compared the effects of instructed extinction on fear conditioned to snakes and spiders and to guns and provide strong evidence that fear conditioned to both classes of stimuli is reduced after instructed extinction with no differences between ontogenetic and phylogenetic stimuli. The current results suggest that when fear relevance is manipulated within-participants fear conditioned to both phylogenetic and ontogenetic, fear-relevant stimuli responds to instructed extinction providing evidence in favor of a socio-cultural explanation for "preparedness" effects.