The role of fear and expectancies in capture of covert attention by spiders

Fear-related stimuli are often prioritized during visual selection but it remains unclear whether capture by salient objects is more likely to occur when individuals fear those objects. In this study, participants with high and low fear of spiders searched for a circle while on some trials a completely irrelevant fear-related (spider) or neutral distractor (butterfly/leaf) was presented simultaneously in the display. Our results show that when you fear spiders and you are not sure whether a spider is going to be present, then any salient distractor (i.e., a butterfly) grabs your attention, suggesting that mere expectation of a spider triggered compulsory monitoring of all irrelevant stimuli. However, neutral stimuli did not grab attention when high spider fearful people knew that a spider could not be present during a block of trials, treating the neutral stimuli just as the low spider fearful people do. Our results show that people that fear spiders inspect potential spider-containing locations in a compulsory fashion even though directing attention to this location is completely irrelevant for the task. Reduction of capture can only be accomplished when people that fear spiders do not expect a spider to be present.     

Depth of processing and recall of threat material in fearful and nonfearful individuals

Although many studies have examined the nature of memory distortions in anxious individuals, few have considered biases in specific memory processes, such as encoding or retrieval. To investigate whether the presentation of threat material facilitates encoding biases, spider fearful (n=63), blood fearful (n=73), and nonfearful (n=75) participants encoded spider related, blood related, and neutral words as a function of three levels of processing (i.e., structural, semantic, and self referent). Participants subsequently completed either a free recall or a recognition task. All participants demonstrated a partial depth of processing effect, such that they recalled more words encoded in the self referent condition than in the other two conditions, but groups did not differ in their recall of stimuli as a function of word type. Relative to participants in the other groups, spider fearful participants had fewer spider related intrusions in the recall condition, and they made fewer errors in responding to structural and semantic encoding questions when spider related words were presented. These results contribute to an increasingly large body of literature suggesting that anxious individuals are not characterized by a memory bias toward threat, and they raise the possibility that individuals with spider fears process threat-relevant information differently than individuals with blood fears.     

Lexical Decision Paradigms do not Differentiate between Fearful and Non-fearful Individuals

Thirty-two spider-fearful, 33 blood/injury/injection fearful, and 28 non-fearful individuals (N = 93) participated in dual-task study. Participants were presented with blood, spider, neutral, positive and pseudo-word stimuli while having to also verbally identify numbers as either even or odd. Blood-fearful individuals responded slower than spider and non-fearful individuals. However, there was no interaction of group membership with stimuli type. This study replicates the results of two previous studies that have used a lexical decision task in an effort to differentiate between fearful and non-fearful individuals and found no significant differences between these two groups on this task. These results suggest that the lexical decision task in general may not be sensitive enough to elicit processing differences in non-clinical samples.     

Depth of processing and recall of threat material in fearful and nonfearful individuals

Abstract

Although many studies have examined the nature of memory distortions in anxious individuals, few have considered biases in specific memory processes, such as encoding or retrieval. To investigate whether the presentation of threat material facilitates encoding biases, spider fearful (n=63), blood fearful (n=73), and nonfearful (n=75) participants encoded spider related, blood related, and neutral words as a function of three levels of processing (i.e., structural, semantic, and self referent). Participants subsequently completed either a free recall or a recognition task. All participants demonstrated a partial depth of processing effect, such that they recalled more words encoded in the self referent condition than in the other two conditions, but groups did not differ in their recall of stimuli as a function of word type. Relative to participants in the other groups, spider fearful participants had fewer spider related intrusions in the recall condition, and they made fewer errors in responding to structural and semantic encoding questions when spider related words were presented. These results contribute to an increasingly large body of literature suggesting that anxious individuals are not characterized by a memory bias toward threat, and they raise the possibility that individuals with spider fears process threat-relevant information differently than individuals with blood fears.     

A pictorial version of the Extrinsic Affective Simon Task: sensitivity to generally affective and phobia-relevant stimuli in high and low spider fearful individuals

This study assessed whether a pictorial, rather than a verbal, Extrinsic Affective Simon Task (EAST: De Houwer, 2003) is, 1) sensitive to the affective valence of normatively positive, neutral, and negative pictures, 2) sensitive to interindividual differences pertaining to fear-relevant affective associations, and 3) a valid predictor for strategic and/or reflexive fear responses. High (n = 35) and low (n = 35) spider fearful individuals completed an EAST comprising of universal positive, negative, neutral, and spider pictures. The pictorial EAST was sensitive to normatively valenced stimuli, tended to differentiate between high and low fearful individuals with respect to spider pictures, and showed independent predictive validity for avoidance behavior.     

Fear makes you stronger: Responding to feared animal targets in visual search

To investigate whether fear affects the strength with which responses are made, 12 animal-fearful individuals (five snake fearful and seven spider fearful) were instructed to decide as quickly as possible whether an animal target from a deviant category was present in a 3 × 4 item (animal) search array. The animal categories were snakes, spiders, and cats. Response force was measured, in newtons. The results showed that the strength of the response was greater when the feared animal served as the target than when it served as the distractors. This finding was corroborated by evoked heart rate changes to the stimuli. Our findings strengthen the argument that focused attention on a single, feared animal can lead to increases in manual force.     

To look or not to look: an eye movement study of hypervigilance during change detection in high and low spider fearful students

Previous eye movement studies of attentional bias in spider fear reported inconsistent results with respect to early attentional capture, suggesting that overt attentional capture only reliably occurs under specific circumstances. In addition, none of these studies explored covert attention. The present study examined attentional bias in spider phobia using a change detection paradigm that was expected to provide good conditions for documenting attentional capture. In contrast to our expectations, eye movement data showed that all participants' first fixations were fastest on general negative targets, whereas participants' first fixations on spider targets were slower in the spider fearful than in the nonfearful group. In addition, spider fearful participants made more nontarget fixations before fixating on a spider target than did nonfearful participants. Thus, we found that participants' overt attention was more quickly focused on general negative targets, whereas covert attentional processes enabled initial avoidance of fear-relevant (i.e. spider) stimuli. The present findings have important implications for research on attention and fear as they indicate that fearful individuals are not characterized by static attentional orienting toward threat but, under certain conditions, may avert attention from threat automatically.     

In the grip of fear: Dissociations in attentional processing of animal fearful individuals

Using a modified attention paradigm we investigated specific attentional mechanisms in processing animal feared stimuli. In this paradigm arrays of four pictures were displayed and after its disappearance from view a probe (a letter, X or P) then followed unpredictably in the location of one of the four pictures. The results showed that discriminations of probes tended to be impeded by spider stimuli, compared to snake stimuli. This effect was potentiated by high anxiety but only for those individuals fearful of spiders, since no such effect was observed for snake fearful individuals. Moreover, the discrimination of the probes was not facilitated when presented after the feared stimuli. The implications of these findings are discussed as a function of the cognitive bias involved in specific fear.     

Some animal specific fears are more specific than others: Evidence from attention and emotion measures

Using a visual search methodology we investigated the effect of feared animal stimuli on attention. Our results confirmed the important role of emotion on attention. All participants detected fear-relevant stimuli (snakes and spiders) faster than neutral (mushrooms) ones against a background of fruits. In addition, spider fearful participants were sensitized specifically to detect their feared stimulus (spiders), compared to their fear-relevant but non-feared (snakes) and neutral stimuli. However, for participants fearful of snakes there was no significant difference in detection latencies between the feared (snakes) and the fear-relevant but non-feared animal stimuli (spiders). The results from the attention task were mirrored in the emotional ratings, which showed that spider fear was highly specific, whereas snake fear was associated with a more generalized enhanced evaluation of all negative stimuli.     

Tracking fear in snake and spider fearful participants during visual search: A multi-response domain study

In visual search tasks snake or spider fearful participants showed shorter reaction times (RTs) to respond to their feared animal (e.g., snake) than to the nonfeared animal (i.e., spider) (Öhman, Flykt, & Esteves, 2001). Here, we used this paradigm with heart rate (HR), RTs, and event-related potential (ERP) measures, to investigate the nature of the responses to the feared animal, a nonfeared (but fear-relevant) animal, and fear-irrelevant target stimuli with snake fearful, spider fearful, and nonfearful participants. Fearful participants showed shorter RTs and evoked larger amplitudes on a late positive potential (LPP; 500–700 ms) for their feared compared to the nonfeared and the fear-irrelevant targets. No relevant significant differences were found on early ERP components and HR measures. These findings do not support an involvement of early information processing in the detection of the feared animal in fearful participants, they favour instead a more elaborated analysis of these complex stimuli to achieve the detection.     

The Effect of d-Cycloserine on Subliminal Cue Exposure in Spider Fearful Individuals

Research on d-cycloserine (DCS) has demonstrated a significant effect on symptom reduction in human studies that utilized conventional exposure-based approaches. Recent studies have offered promising results for targeting fears through subliminal paradigms. In this double-blind, randomized placebo-controlled study, 45 spider fearful individuals received DCS or placebo pills prior to completing a subliminal cue exposure task to images of spiders. Participants completed self-report questionnaires and a behavioral approach task to a live caged tarantula. After repeated exposure to subliminal spider cues, participants in the DCS group reported a greater reduction in disgust than individuals in the placebo group. No difference was observed in fear ratings. These findings suggest that DCS augments the reduction in disgust in spider fearful subjects after subliminal exposure to spider cues.     

Perceptual separability and spatial models

Highly analyzable two-dimensional color stimuli were generated using stimulus cards such that one part of each card varied only on the first dimension and the other part varied only on the second. Subjects were required to make judgments of similarity between pairs of these analyzable stimuli, between pairs of relatively unanalyzable color stimuli, and between pairs of geometric stimuli. The results support previous findings that the Euclidean combining rule is appropriate for judgments of single color patches but indicate that the city block combining rule may be appropriate for simple stimuli that vary on perceptually distinct dimensions.     

Spider fearful individuals attend to threat, then quickly avoid it: evidence from eye movements

According to cognitive models of anxiety, anxiety patients exhibit an early reflexive attentional bias toward threat stimuli, which may be followed by intentional avoidance of these stimuli. To determine the time course of attentional vigilance and avoidance, the authors conducted an eye-tracking study in which 22 highly spider fearful participants (SFs) and 23 nonanxious control participants (NACs) studied groups of 4 pictures (spider, butterfly, dog, and cat). The authors found that the very first fixation was on a spider picture more often in SFs than in NACs. However, SFs quickly moved their eyes away from the spider they had fixated first, yielding shorter gaze durations than NACs. Afterward, SFs exhibited shorter gaze durations on spiders than NACs for the rest of the 1-min presentation time. This early reflexive attentional bias toward threat followed by avoidance of threat may explain earlier failures to find attentional biases in anxiety.     

Contamination vs. harm-relevant outcome expectancies and covariation bias in spider phobia

There is increasing evidence that spiders are not feared because of harmful outcome expectancies but because of disgust and contamination-relevant outcome expectancies. This study investigated the relative strength of contamination- and harm-relevant UCS expectancies and covariation bias in spider phobia. High (n=25) and low (n=24) spider fearful individuals saw a series of slides comprising spiders, pitbulls, maggots, and rabbits. Slides were randomly paired with either a harm-relevant outcome (electrical shock), a contamination-related outcome (drinking of a distasting fluid), or nothing. Spider fearful individuals displayed a contamination-relevant UCS expectancy bias associated with spiders, whereas controls displayed a harm-relevant expectancy bias. There was no evidence for a (differential) postexperimental covariation bias; thus the biased expectancies were not robust against refutation. The present findings add to the evidence that contamination ideation is critically involved in spider phobia.     

Emotional responding to fearful and disgusting stimuli in specific phobics

Individuals with small animal and blood-injection-injury (BII) phobias respond to phobia-relevant stimuli with both fear and disgust. However, recent studies suggest that fear is the dominant emotional response in animal phobics whereas disgust is the primary emotional response in BII phobics. The present study examined emotional responding toward pictures of spiders, surgical procedures, and two categories of general disgust elicitors (rotting food and body products) among analogue spider phobics, BII phobics, and nonphobics. Dominant emotional responses to phobia-relevant stimuli clearly differentiated the groups. as spider phobics were more likely to be classified as primarily fearful when rating pictures of spiders (74%), whereas BII phobics were more likely to be classified as primarily disgusted when rating pictures of surgical procedures (78%). Discriminant function analyses revealed that disgust ratings, but not fear ratings, of the phobic pictures were significant predictors of phobic group membership. Both phobic groups were characterized by elevated disgust sensitivity toward video and pictorial general disgust elicitors. Implications and suggestions for continued research examining fearful and disgusting stimuli in specific phobia are outlined.     

Sensitivity and response bias in fear of spiders

According to cognitive theories of anxiety, phobic patients are searching the environment for threatening stimuli, and detecting them rapidly. However, previous studies failed to find a lowered perceptual threshold for threatening stimuli in specific phobias. Therefore, two experiments applying a signal detection paradigm were conducted. Highly spider fearful and nonfearful participants were asked to decide whether a picture of a spider, beetle, or butterfly was presented. In both experiments, spider fearfuls were not better at detecting spiders, or any other animal, than healthy controls. Instead, spider fearfuls were more liberal in assuming that they had seen a spider or a beetle. In accord with earlier studies, these results suggest that spider phobics may exhibit an interpretation bias rather than improved detection of threat.     

The effects of familiarity in a perceptual matching task

Latencies of same-different judgments to pairs of two-digit numerals were recorded for stimuli presented in familiar or unfamiliar (inverted) orientation. Familiar stimuli were responded to more quickly than unfamiliar. For both stimulus types, latencies were correlated with the syllable length of the verbal representation of the numerals, allowing the interpretation that the effect of stimulus orientation is on encoding processes. In two other experiments, it was found that familiarity had no effect on different judgments when the stimuli were relatively simple (e.g., a single digit), but did affect different judgments with more complex stimuli. These results were related to the hypothesis that the complexity of verbal material determines whether different judgments are instigated by visual or by verbal representations of the stimuli.     

Animal phobias versus claustrophobias: Exteroceptive versus interoceptive cues

The overall purpose of this investigation was to examine heterogeneity among specific phobias. In particular, the goals were to compare features of fear responding between individuals fearful of claustrophobic situations and individuals fearful of spiders/snakes, and to compare their response to hyperventilation challenges. By so doing, specific predictions were tested in relation to a conceptual model of exteroceptive and interoceptive fear cues. Using a nonclinical sample, 19 subjects with spider/snake phobias, 18 nonphobies, and 9 subjects with claustrophobias were exposed on two separate occasions to a live tarantula or python, a small closet, and a hyperventilation challenge. Dependent measures included subjective anxiety, panic attacks, physical symptoms, cognitive symptoms (or, fear of symptoms) and heart rate. In addition, subjects completed a standardized self-report scale that measures fear of bodily symptoms of arousal. It was found that subjects with claustrophobia reported more physical symptoms and cognitive symptoms than did subjects with snake/spider phobias, in response to their fear-relevant stimulus. In addition, claustrophobic subjects were more fearful of hyperventilation challenges and reported more fear of bodily symptoms, than did snake/spider phobic subjects. Finally, subjects with claustrophobia were as fearful of hyperventilation as they were of their fear-relevant stimulus. Theoretical and empirical implications of these findings are discussed.     

Relative and absolute duration judgments under prospective and retrospective paradigms

A dual-process contingency model of short duration judgment is proposed and tested. The first process, or P(t), is a timer that uses cognitive capacity to keep track of units of time. If capacity is directed toward other tasks, P(t) will record fewer units and produce lower time judgments than when capacity is not directed toward other tasks. This timing process is most likely to affect performance when people know in advance (prospective judgments) that time judgments will be required and when absolute, rather than relative, judgments are made. The second process, or P(m), which is used for retrospective and relative judgments, judges duration on the basis of the number of remembered high priority events (HPEs) occurring during the interval. When this process is used, time judgments increase with the amount of HPEs that can be retrieved at the moment of judgment. Two experiments are reported. Tactual stimuli were presented, and nontemporal information processing load (simple or complex stimuli), type of judgment (absolute or relative), and judgment paradigm (prospective or retrospective)were manipulated. The results obtained support the proposed dual-process contingency model.     

Multisensory temporal order judgments: when two locations are better than one

In Experiment 1, participants were presented with pairs of stimuli (one visual and the other tactile) from the left and/or right of fixation at varying stimulus onset asynchronies and were required to make unspeeded temporal order judgments (TOJs) regarding which modality was presented first. When the participants adopted an uncrossed-hands posture, just noticeable differences (JNDs) were lower (i.e., multisensory TOJs were more precise) when stimuli were presented from different positions, rather than from the same position. This spatial redundancy benefit was reduced when the participants adopted a crossed-hands posture, suggesting a failure to remap visuotactile space appropriately. In Experiment 2, JNDs were also lower when pairs of auditory and visual stimuli were presented from different positions, rather than from the same position. Taken together, these results demonstrate that people can use redundant spatial cues to facilitate their performance on multisensory TOJ tasks and suggest that previous studies may have systematically overestimated the precision with which people can make such judgments. These results highlight the intimate link between spatial and temporal factors in determining our perception of the multimodal objects and events in the world around us.