Automatic Attention Does Not Equal Automatic Fear ...

Emotion 2007, Vol. 7, No. 2, 314 –323

Copyright 2007 by the American Psychological Association 1528-3542/07/$12.00 DOI: 10.1037/1528-3542.7.2.314

Automatic Attention Does Not Equal Automatic Fear: Preferential Attention Without Implicit Valence Helena M. Purkis and Ottmar V. Lipp University of Queensland Theories of nonassociative fear acquisition hold that humans have an innate predisposition for some fears, such as fear of snakes and spiders. This predisposition may be mediated by an evolved fear module ¨ hman & Mineka, 2001) that responds to basic perceptual features of threat stimuli by directing (O attention preferentially and generating an automatic fear response. Visual search and affective priming tasks were used to examine attentional processing and implicit evaluation of snake and spider pictures in participants with different explicit attitudes; controls (n ⫽ 25) and snake and spider experts (n ⫽ 23). Attentional processing and explicit evaluation were found to diverge; snakes and spiders were preferentially attended to by all participants; however, they were negative only for controls. Implicit evaluations of dangerous and nondangerous snakes and spiders, which have similar perceptual features, differed for expert participants, but not for controls. The authors suggest that although snakes and spiders are preferentially attended to, negative evaluations are not automatically elicited during this processing. Keywords: fear relevance, preferential attention, implicit valence

propose that the fear module detects fear-relevant stimuli preferentially according to basic perceptual features and produces an automatic and encapsulated fear response. “Fear is a strong, stimulus-driven aversive response that may be evoked by incompletely processed stimuli, and particularly by features of threat stimuli that derive their potency from evolution¨ hman & Wiens, 2004, p. 72). ary sources” (O ¨ hman, Flykt, and Esteves (2001) have provided support for the O preferential detection of fear-relevant stimuli using a modified visual search task. Participants are presented with grids of four or nine pictures of snakes, spiders, flowers, or mushrooms. The pictures are either all from the same category or include a deviant picture. The time taken to detect the presence or absence of a deviant is then used to infer the speed of attentional capture by that ¨ hman and colleagues have category of stimulus. Using this task, O repeatedly demonstrated that fear-relevant pictures (snakes and spiders) are detected more quickly among grids of non-fearrelevant pictures (flowers and mushrooms) than vice versa. Moreover, they claim that search for snakes and spiders is more efficient (search time does not increase substantially with grid size) than is search for flowers and mushrooms. Recent research, however, has shown that ontogenetically (modern) fear-relevant stimuli are also preferentially detected in visual search tasks (Blanchette, 2006; Brosch & Sharma, 2005). These studies compared visual search for phylogenetically fear-relevant stimuli (pictures of snakes and spiders) to search for ontogenetically fear-relevant stimuli (pictures of guns and syringes), finding that all fear-relevant stimuli were preferentially attended to compared with non-fear-relevant stimuli. Moreover, search for fear-relevant stimuli, whether phylogenetic or ontogenetic, was more efficient than search for non-fear-relevant stimuli. Search time for fear-relevant stimuli, both phylogenetic and ontogenetic, did not increase substantially as grid size increased, whereas search time increased with

Evolutionarily fear-relevant stimuli, such as snakes, spiders, and heights, are more easily associated with fear and are preferentially attended to relative to non-fear-relevant stimuli. Theories of nonassociative fear acquisition hold that humans have an innate predisposition for some fears that does not require conditioning or learning processes (Rachman, 2002). These models propose that fear relevance is a product of Darwinian natural selection, in that selection is said to have favored individuals who displayed some fear on first contact with a potentially dangerous stimulus. According to such a model, a learning experience is not required for a fear-relevant stimulus to elicit a fear response. Thus, all people should evidence an automatic fear response to snakes and spiders. This automaticity has been proposed to reflect on an evolved fear module that preferentially detects these stimuli and generates ¨ hman & Mineka, 2001). This module is realized a fear response (O in neural circuitry centered on the amygdala and is proposed to ¨ hman and Wiens operate independently of conscious cognition. O (2004) described the fear module as selective, in that it responds only to stimuli that were related to threatening encounters across evolution. The module is proposed to be automatic, in that it operates at a subcortical level and responds to the basic perceptual features of stimuli rather than involving meaningful recognition. In addition, the module is said to be encapsulated, in that once activated, it is not influenced by other processes. These authors

Helena M. Purkis and Ottmar V. Lipp, School of Psychology, University of Queensland, Australia. This research was completed as part of Helena M. Rurkis’ doctoral work in psychology and was supported by an Australian Postgraduate Award scholarship. Correspondence concerning this article should be addressed to Helena M. Purkis or Ottmar V. Lipp, School of Psychology, University of Queensland, Queensland 4072, Australia. E-mail: [email protected] or [email protected] 314

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increasing grid size for non-fear-relevant stimuli. This research suggested that fear-relevant stimuli, whether phylogenetic or ontogenetic, are preferentially processed. Although both phylogenetic and ontogenetic stimuli are preferentially processed, an innate fear response should be present only ¨ hman for phylogenetic fear-relevant stimuli. Several studies (see O & Mineka, 2001 for a review) investigated the automatic processing of fear-relevant stimuli with a backward-masking technique, presenting the stimulus of interest quickly followed by a masking stimulus. Backward masking permits perception of the initial stim¨ hman and Soares ulus but prevents its conscious recognition. O (1994) presented snake- and spider-fearful participants, as well as nonfearful controls, with masked and unmasked pictures of snakes, spiders, flowers, and mushrooms. In both the masked and unmasked conditions, snake-fearful participants showed increased skin conductance responses to snake pictures as compared with the other pictures, and spider-fearful participants showed increased skin conductance responses to spider pictures as compared with the other pictures. However, nonphobic participants did not show increased skin conductance responses to masked presentations of snake or spider pictures, as would be expected if these stimuli were being preferentially processed and an automatic fear response generated. An alternative paradigm for investigating the automatic evaluation of stimuli are implicit, reaction-time-based measures (see Fazio & Olson, 2003, for a review of implicit measures). Affective priming in particular has gained recent popularity (see Klauer & Musch, 2003, for a review). A priming task presents two stimuli, a prime and a target, that are similar to some extent on a particular dimension. The participant performs a reaction-time task to the target, and the similarity between prime and target is reflected in the speeding of this response. In affective priming, prime and target stimuli are selected on the basis of affective valence. Participants are required to make a response following presentation of the target, and it has been shown that a prime and target of similar valence will reduce reaction time, whereas a valence mismatch will increase reaction time. Although conceptually similar to semantic priming, affective priming reflects response competition, as observed in the Stroop effect, in that responses automatically activated to prime and target may be congruent or incongruent with each other. Activation of congruent responses facilitates response time, whereas activation of incongruent responses increases response time (see De Houwer, 2003). Affective priming is considered, therefore, to reflect automatic attitude activation, and as such may or may not correspond with measures of explicit attitudes. In a study of racial attitudes, implicit attitudes as measured by affective priming and explicit attitudes as measured by self-report were found to be similar only in individuals who were unmotivated to control their prejudiced reactions (Fazio, Jackson, Dunton, & Williams, 1995). In comparison to self-report measures, affective priming therefore provides an attitude measure that is less subject to demand characteristics and more sensitive to the spontaneous and automatic evaluation of a stimulus (De Houwer, 2003). In the current research, affective priming is used as an indicator of the implicit valence of a stimulus, whereby negative valence may indicate that a fear response is elicited by that stimulus. The current research examined whether, in addition to preferential attentional processing, fear-relevant stimuli elicit a negative

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evaluation that is automatic and activated on the basis of the perceptual features of the stimulus. Previous research has found that fear-relevant stimuli evidence negative valence in an affective priming task and are preferentially attended to in a visual search task, relative to non-fear-relevant stimuli. Moreover, these results were obtained across unselected participants (Purkis & Lipp, 2006), suggesting that in addition to preferential processing, an automatic, negative response to fear-relevant stimuli was elicited in all participants. However, most people tend to have negative explicit attitudes toward snakes and spiders. In a preexperimental questionnaire, Purkis and Lipp found that unselected participants rated snakes and spiders as more negative than birds, fish, and dogs. To confirm that a negative response is automatically activated, it is necessary to show that presentation of an evolutionarily fear-relevant stimulus produces an automatic, negative response regardless of explicit attitudes toward that stimulus. The current research therefore investigated the implicit valence and attentional processing of pictures of snakes and spiders in two groups of participants who differed in their explicit attitudes toward snakes and spiders. The responses of an unselected control group and a group of snake and spider experts, consisting of reptile and spider handlers, entomologists, herpetologists, and other snake and spider enthusiasts, were compared. The valence of pictures of fear-relevant, snake and spider, and non-fear-relevant animal stimuli was assessed using verbal ratings and affective priming measures, and attentional processing was assessed using visual search. If the presentation of pictures of snakes and spiders automatically elicits negative valence, implicit measures should reflect this regardless of explicit attitudes toward snakes and spiders. In the current study, we therefore predicted that although ratings of snakes and spiders compared with other animals would differ across groups, affective priming would show snakes and spiders to be negative for all participants. In addition, we expected that snakes and spiders would be preferentially attended to relative to other animals by all participants. Moreover, the current research explicitly investigated the proposal that fear-relevant stimuli are processed on the basis of basic perceptual features. As the sample group included people with expert knowledge regarding snakes and spiders, we were able to assess whether implicit processing of snake and spider pictures differed on the basis of the dangerousness of the snake and spider exemplars. Dangerousness is a factor that does not involve differences in basic perceptual features, but rather would require stimulus identification. Therefore we predicted that if stimuli were processed on the basis of basic perceptual features, affective priming would reveal all snakes and spiders, regardless of dangerousness, to be implicitly negative for all participants. Each participant rated each stimulus for pleasantness and for how fear evoking it was. Affective priming provided an indirect index of valence as in previous research (Fazio & Olson, 2003; Klauer & Musch, 2003; Purkis & Lipp, 2006). The effect of the dangerousness of the fear-relevant stimuli was assessed in two affective priming tasks in which snake and spider pictures were of dangerous animals, a taipan snake and a funnel web spider, or of nondangerous animals, a green python snake and a water spider. Visual search, an index of attentional processing (Treisman, 1969), was used to investigate attention to fear-relevant and non-fearrelevant stimuli. The visual search task used the same stimuli as ¨ hman et al. (2001): snakes, spiders, flowers, and mushrooms. did O

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316 Method Participants

Twenty-five first-year psychology students participated in exchange for course credit and 23 members of the general public, recruited by advertisement on the basis of prior experience or expertise with snakes or spiders, were paid for their participation. Participants provided informed consent before the experiment began. Participants were assigned to the control or expert group on the basis of their experience with snakes and spiders. The control group consisted of 22 participants (7 men and 15 women), between 18 and 37 years old (mean age ⫽ 20), and the expert group consisted of 26 participants (13 men and 13 women), between 18 and 63 years old (mean age ⫽ 30).

Apparatus The experiment consisted of three questionnaires, two valencerelated priming tasks with targets from varied categories, a visual search task, and two priming tasks with primes of varied dangerousness. The dangerousness-related priming tasks used pictures of a snake, a spider, a horse, and a cat as primes. One of the tasks used pictures of a dangerous snake and spider (a taipan snake and a funnel web spider) and the other task used pictures of a nondangerous snake and spider (a green python snake and a water spider). The pictures depicted the dangerous and nondangerous animals in similar, stationary, nonthreatening poses. The word stimuli for these tasks were obtained from Mathews, Mogg, Kentish, and Eysenck (1995) and consisted of the six positive words confident, excellent, praise, pleasure, delight, and cheerful and the six negative, physical threat words violence, pain, injury, fatal, killer, and lethal. The valence-related priming tasks used the nondangerous snake and spider pictures in addition to the horse and cat primes. The target words were obtained from Teachman, Gregg, and Woody (2001) and had been matched for length and ease of categorization. Each task contained four positive and four negative targets. These were good, great, wonderful, nice, bad, awful, terrible, and evil and unafraid, calm, relaxed, tranquil, afraid, scared, frightened, and alarmed. Data were averaged across the two tasks. The visual search task used stimuli similar to those used ¨ hman et al. (2001): 10 pictures each of snakes, spiders, by O flowers, and mushrooms. Pictures were obtained from a set previously used in our laboratory, and additional pictures for the priming tasks were collected from the Internet and modified using Jasc PaintShop Pro software (1999), so that they were of standard height, width, and color depth (260 ⫻ 195 ⫻ 256 pixels, stored with the websave palette, error diffusion method). Word stimuli were created and stored in a similar fashion (28-point bold Arial font, white, centered on a black background 400 ⫻ 400 ⫻ 256 pixels, saved using websave palette, error diffusion method). Pictures are available on request. Questionnaires involved the Emotionality and Sociability Inventory (EASI) personality measure (Buss & Plomin, 1975), the Fear Survey Schedule (FSS–III; Arrindell, Emmelkamp, & Van der Ende, 1984), and a custom designed valence–fear questionnaire that required participants to rate the stimulus categories dogs, birds, fish, cats, horses, snakes, and spiders on a 7-point Likertstyle scale ranging from 3 ( pleasant) to ⫺3 (unpleasant) and to

answer five questions related to fear of each category (e.g., “Would you go out of your way to avoid being near any of the following animals?”). In addition, participants answered the question “Please provide a few brief details about your experiences with snakes/spiders.” This question was used to allocate participants to groups on the basis of their expertise with snakes and spiders.

Procedure The experiment was conducted on a Dell Pentium notebook computer and was controlled by custom-written software running under Windows 98. Tasks were presented on the 14-in. (35.56-cm) notebook computer screen, and participants sat facing the screen at a distance of 70 cm. A button box with two buttons was connected to the games port of the computer and was used to record responses. The buttons had a diameter of 1 cm and were 4 cm apart from center to center. Labels relevant for the given task were affixed to the button box, one immediately above each button. Participants were given experimental instructions on arrival and provided informed consent before the experiment commenced. They completed the EASI, FSS–III, and custom valence–fear questionnaires. In addition, they provided a short report regarding the nature of their experience with snakes and spiders. The experiment proper consisted of the series of priming and visual search tasks. The order of experimental tasks was randomized across the experiment with the restriction that the dangerousness-related priming tasks were completed together, the valence-related priming tasks were completed together, and visual search tasks were completed in between these blocks of priming tasks.

Priming Tasks Participants were asked to evaluate a word preceded by a picture on a computer screen. They were instructed to classify each word as positive or negative by pressing the corresponding button on the button box. Buttons on the button box were labeled Positive and Negative during this task. The response button marked Positive was always on the right (Hermans, Vansteenwegen, Crombez, Baeyens, & Eelen, 2002). The two valence-related priming tasks each consisted of 64 trials (two blocks of 4 primes ⫻ 8 targets, trials randomly ordered within blocks), the dangerousness-related tasks consisted of 96 trials (two blocks of 4 primes ⫻ 12 targets, trials randomly ordered within blocks). Each trial began with the presentation of a black control screen containing a fixation cross (white, 2 cm ⫻ 2 cm, subtending 1.64° ⫻ 1.64°) for 200 ms, followed by a picture prime presented for 200 ms, a black control screen presented for 100 ms, and a target word presented for 10 s or until participants responded with a button press. During the priming tasks, pictures were presented on a black background, and the words were presented in white on a black background. Pictures were 260 ⫻ 195 pixels in size and subtended 5.53° ⫻ 4.15° of visual angle. Fixation cross, picture, and word were always presented in the center of the screen. The intertrial interval was 1 s. Participants were instructed to be as fast and accurate as possible in their responses. Before the experiment began, participants were given a practice sequence consisting of 10 trials to check their understanding of the task.


Visual Search Task Participants were presented with grids of nine pictures. Either pictures all belonged to the same category (a no-deviant trial), or there was one deviant picture present from a different category (a deviant trial). Pictures in each grid background were sampled at random from the 10 pictures available for that category, such that each picture in a background was a different exemplar from the same category. The buttons on the button box were labeled Same or Different and participants were instructed to press the relevant button, Same if all pictures were of the same category and Different if there was a deviant picture present. The button to the right was labeled Different for all participants. The task consisted of 164 trials presented without interruption, 108 deviant trials (4 backgrounds ⫻ 3 deviants ⫻ 9 grid positions) randomly distributed among 56 no-deviant trials. Trials were ordered at random with the restriction that no more than three consecutive backgrounds were the same and no more than two consecutive deviants occupied the same grid position. Of the 10 available pictures, 9 were chosen at random from each category to be used as deviants such that a different exemplar was presented in each of the nine grid positions, and each category exemplar was used only once as a deviant. Backgrounds consisted of 8 or 9 of the 10 available pictures for a given category selected at random and were ordered randomly in the grid. Each trial began with a fixation cross (white, 2 cm ⫻ 2 cm, subtending 1.64° ⫻ 1.64°) in the center of the screen for 1,000 ms, followed by a grid. The grid remained for 4 s or until the participant responded with a button press. The intertrial interval was 1 s. The computer screen was black during control screens, and pictures were presented in grids of nine pictures in a 3 ⫻ 3 matrix. Shapes were 260 ⫻ 195 pixels in size (5.53° ⫻ 4.15° of visual angle if presented centered) and were surrounded by a white frame 1 pixel wide and touching edge to edge. The grid subtended 16.9° ⫻ 12.7° of visual angle. Before the task proper began, participants were given a practice sequence consisting of 10 grid presentations to check that they understood the task. Participants were instructed to respond as quickly and accurately as possible.

Scoring and Response Definition Experts were defined on the basis of questionnaire information as people who had at some time in their life had regular experience handling snakes or spiders. To be classified as expert, a participant had to have previously owned a pet snake or spider for at least 6 months or worked in an area where regular handling of snakes or spiders was required once a week or more for 6 months. Three participants from the control sample met the criteria for experts and were reallocated. Expert participants were classified as those having expertise with spiders, snakes, or both. Six experts had experience with one but not both animals, and data from trials that depicted the fear-relevant animal for which they had no expertise were excluded from the main analyses. For example, an expert who worked with snakes but not spiders contributed evaluation and visual search times from cat, horse, and snake trials, but not spider trials. Responses on the FSS–III measure were combined to yield an overall score for fearfulness for each participant. The EASI personality measure was scored separately for each subscale: Emo-

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tionality— general, fear, and anger; Activity—tempo and vigor; Sociability; Impulsivity—inhibitory control and decision time; Sensation Seeking; and Persistence, creating 10 variables. Evaluation times in the priming tasks were examined for each participant, and outliers, defined as responses that were slower than 1,000 ms or faster than 100 ms, were removed. Errors were defined as incorrect responses, for example, pressing the button labeled negative during a positive word, and these responses were not scored. Visual search task data were examined, and responses slower than 2,000 ms or faster than 100 ms were defined as outliers and excluded from analyses. Errors were defined as incorrect responses (e.g., pressing the button labeled same during a different trial) and were not scored. Accuracy data were scored on a percentage correct basis, where higher numbers reflect higher accuracy. Three participants provided incomplete questionnaire data and were excluded from the relevant analyses. No more than 2% of reaction times from priming and visual search tasks were removed as outliers. Multivariate statistics, Pillai’s Trace, and independent groups t tests reported for questionnaire analyses were obtained using SPSS statistical software, version 11.5.1. Follow-up, two-tailed t tests were conducted using tables of critical values based on Sidak’s multiplicative inequality to protect against the accumulation of alpha error (Rohlf & Sokal, 1981), and where necessary, Greenhouse-Geisser corrected mean square errors and degrees of freedom were used to protect against violation of the assumption of sphericity. The two groups used in the current study differed in average age and in speed of response on the reaction-time tasks. Reaction time and accuracy data were therefore analyzed within groups with paired-samples t tests. Results and critical values for pairedsamples t tests were obtained using the SPSS statistical software, and effect size correlations were calculated as r (Rosenthal, & DiMatteo, 2001).

Results Questionnaires Responses on the custom fear questionnaire for the valence questions and for the five fear questions were averaged across cats and horses and snakes and spiders and compared between control and expert participants. Data were analyzed in 2 ⫻ 2 (Fear Relevance ⫻ Group) analyses of variance separately for fear and like– dislike. Control participants liked snakes and spiders less than cats and horses, whereas there was no difference for expert participants. This impression was confirmed with a main effect for fear relevance, F(1, 45) ⫽ 63.95, p ⬍ .001, and a Fear Relevance ⫻ Group interaction, F(1, 45) ⫽ 78.73, p ⬍ .001. Follow-up tests confirmed that control participants liked snakes and spiders less than cats and horses (2.2 vs. 5.5), t(45) ⫽ 11.34, p ⬍ .01, r ⫽ .86, whereas experts did not differ (6.04 vs. 6.21), t(45) ⬍ 1. Control participants were also more fearful of snakes and spiders than of cats and horses, whereas expert participants did not display a difference in fear levels, as indicated by a main effect for fear relevance, F(1, 43) ⫽ 39.66, p ⬍ .001, and a Fear Relevance ⫻ Group interaction, F(1, 43) ⫽ 35.66, p ⬍ .001. Follow-up tests confirmed that control participants were more fearful of snakes and spiders than of horses and cats (2 vs. 0.48), t(43) ⫽ 8.41, p ⬍ .01, r ⫽ .79, whereas experts were not (0.63 vs. 0.58), t(43) ⬍ 1.

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The FSS–III and the EASI indicated that control participants had a higher overall level of fear than expert participants, and the EASI revealed that controls had a higher level of general emotionality than experts. FSS–III means for controls and experts were compared with an independent groups t test. Controls reported a higher level of overall fear than experts (20 vs. 15.33), t(40) ⫽ 5.73, p ⬍ .001, r ⫽ .67. EASI questionnaire means for each subscale were compared between controls and experts with independent groups t tests. Controls reported a higher level of general emotionality (15.79 vs. 12.33), t(42) ⫽ 3.17, p ⬍ .01, r ⫽ .44, and fear (14.52 vs. 11.9), t(43) ⫽ 3.29, p ⬍ .01, r ⫽ .45, than did experts. Groups did not differ on anger (13.3 vs. 12), tempo (13.8 vs. 15.5), vigor (14.9 vs. 16.7), Sociability (17.8 vs. 16.1), inhibitory control (14.8 vs. 13.4), decision time (14.4 vs. 15), Sensation Seeking (15.3 vs. 16.3), or Persistence (11.9 vs. 10.6; all ps ⬎ .1).

Implicit Valence As can be seen in Figure 1, responses from control participants indicated that they found snakes and spiders to be more negative than other animals, a difference not found in expert participants, who indicated that they found snakes and spiders to be more positive than other animals. Control participants evaluated positive targets more quickly when they were preceded by non-fear-relevant animals than by snakes and spiders, t(20) ⫽ 3.76, p ⬍ .001, r ⫽ .64. Control participants also tended to evaluate negative targets more quickly when they were preceded by fear-relevant than by non-fearrelevant primes, t(20) ⫽ 2.05, p ⫽ .054, r ⫽ .42. Expert participants displayed no difference in evaluation times for positive targets (t ⬍ 1); however, they evaluated negative targets more quickly when preceded by non-fear-relevant than by fear-relevant primes, t(24) ⫽ 2.11, p ⬍ .05, r ⫽ .40. All participants were less accurate in evaluating positive targets when preceded by fear-relevant than by non-fear-relevant primes; controls, t(20) ⫽ 4.27, p ⬍ .001, r ⫽ .69; experts, t(25) ⫽ 3.71, p ⬍ .001, r ⫽ .60. The accuracy of evaluating negative targets did not differ (all ts ⬍ 1.6). The accuracy data are contraindicative of a speed–accuracy trade-off.

Preferential Attention As can be seen in Figure 2, both expert and control participants showed preferential attention for fear-relevant pictures, in that both groups detected fear-relevant deviants among non-fear-relevant backgrounds more quickly than they did non-fear-relevant deviants among fear-relevant backgrounds. Control participants detected the absence of a deviant more quickly when the background was fear relevant than non–fear relevant, t(20) ⫽ 3.56, p ⬍ .005, r ⫽ .62; participants detected fear-relevant deviants among fear-relevant backgrounds more quickly than they did non-fear-relevant deviants among non-fearrelevant backgrounds, t(20) ⫽ 5.95, p ⬍ .001, r ⫽ .80, and fear-relevant deviants were detected among non-fear-relevant backgrounds more quickly than were non-fear-relevant deviants among fear-relevant backgrounds, t(20) ⫽ 4.79, p ⬍ .001, r ⫽ .73. Participants were less accurate in detecting non-fear-relevant deviants among fear-relevant backgrounds than fear-relevant deviants among non-fear-relevant backgrounds, t(20) ⫽ 2.47, p ⬍ .05,

r ⫽ .48, a result contraindicative of a speed–accuracy trade-off (all other comparisons, ts ⬍ 1.2). Expert participants detected the absence of a deviant more quickly when the background was fear relevant than non–fear relevant, t(22) ⫽ 2.6, p ⬍ .02, r ⫽ .48; participants detected fear-relevant deviants among fear-relevant backgrounds more quickly than they did non-fear-relevant deviants among non-fearrelevant backgrounds, t(17) ⫽ 4.75, p ⬍ .001, r ⫽ .76, and fear-relevant deviants were detected among non-fear-relevant backgrounds more quickly than were non-fear-relevant deviants among fear-relevant backgrounds, t(22) ⫽ 6.99, p ⬍ .001, r ⫽ .83. Comparisons involving accuracy data were nonsignificant (all ts ⬍ 1.6).

Processing of Dangerousness Control participants. As can be seen in Figure 3, snakes and spiders were more negative than cats and horses for control participants regardless of dangerousness. Control participants were faster to evaluate positive words when preceded by pictures of cats and horses than when preceded by pictures of nondangerous snakes and spiders, t(21) ⫽ 2.5, p ⫽ .021, r ⫽ .48, and faster to evaluate negative words preceded by pictures of nondangerous snakes and spiders than after pictures of cats and horses, t(21) ⫽ 3.74, p ⫽ .001, r ⫽ .63 (upper left panel, Figure 3). Control participants were also faster to evaluate negative words preceded by pictures of dangerous snakes and spiders than by pictures of cats and horses, t(21) ⫽ 2.32, p ⫽ .031, r ⫽ .45, and there was a strong trend for controls to be faster to evaluate positive words preceded by pictures of cats and horses than by pictures of dangerous snakes and spiders, although this did not reach significance, t(21) ⫽ 1.71, p ⫽ .1, r ⫽ .35 (lower left panel, Figure 3) As can be seen in Figure 3 (right panels), controls were more accurate in evaluating positive words preceded by pictures of cats and horses than by pictures of nondangerous, t(21) ⫽ 3.46, p ⫽ .002, r ⫽ .60, and dangerous snakes and spiders, t(21) ⫽ 2.25, p ⫽ .036, r ⫽ .44, and accuracy did not differ significantly for the evaluation of negative words (all ps ⬎ 0.1). The accuracy data do not suggest that the differences in evaluation time reflect a speed– accuracy trade-off. Expert participants. As can be seen in Figure 3, dangerous, but not nondangerous, snakes and spiders were more negative than cats and horses for expert participants. Experts did not show a significant difference in the evaluation of positive or negative words after pictures of cats and horses as compared with pictures of nondangerous snakes and spiders, positive words, t(25) ⬍ 1, and negative words, t(23) ⬍ 1 (upper left panel, Figure 3). However, expert participants were faster to evaluate positive words preceded by pictures of cats and horses than by pictures of dangerous snakes and spiders, t(24) ⫽ 3.04, p ⫽ .006, r ⫽ .53. In addition, experts were faster to evaluate negative words after pictures of dangerous snakes and spiders than after pictures of cats and horses, t(23) ⫽ 2.18, p ⫽ .04, r ⫽ .41 (lower left panel, Figure 3). Expert participants were more accurate in evaluating positive words preceded by pictures of cats and horses than by pictures of nondangerous snakes and spiders, t(25) ⫽ 2.78, p ⫽ .01, r ⫽ .49 (cats and horses vs. dangerous snakes and spiders, p ⬎ .1). Accuracy did not differ for negative targets (both ps ⬎ 0.1). The data do not suggest a speed–accuracy trade-off.


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Figure 1. Reaction time and accuracy (percentage correct) on the valence-related affective priming task in control (upper panel) and expert (lower panel) participants as a function of target valence and prime fear relevance. Error bars reflect standard errors of the mean. FR ⫽ fear-relevant prime; NFR ⫽ non-fear-relevant prime.

Discussion The current study confirmed that snakes and spiders were preferentially attended to by all participants, but it did not support the prediction that all participants would implicitly evaluate all snakes and spiders as negative. Moreover, implicit evaluations of snakes and spiders were affected by their degree of dangerousness in

expert participants. Questionnaire measures confirmed that basic personality characteristics were consistent across participants and that snake and spider experts did not differ from controls on factors such as sensation seeking. Although there was a difference in overall fear levels between experts and controls, it is unlikely that this difference can account for the current pattern of results: no

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Figure 2. Reaction time and accuracy (% correct) on the visual search task in Control (upper panels) and Expert (lower panels) participants as a function of the fear relevance of the background pictures (Fear Relevant vs. Non Fear Relevant) and the nature of the deviant, no deviant, a deviant of the same fear relevance (snake among spiders) or a deviant of the different fear relevance (snake among flowers); error bars reflect standard errors of the mean.

difference between groups on the search task and differences between groups on the affective priming task. Questionnaire measures confirmed that controls and experts differed in their explicit attitudes toward snakes and spiders. Snakes and spiders were reported to be more negative and more

feared relative to non-fear-relevant animals by control but not by expert participants. The results of the affective priming task confirmed this finding, indicating that snakes and spiders were implicitly evaluated as negative by controls, but not by experts. This is an important finding that confirms that experts do not merely


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Figure 3. Reaction time and accuracy (percentage correct) on the dangerousness-related affective priming tasks with pictures of nondangerous snakes and spiders (upper panels) and of dangerous snakes and spiders (lower panels) as a function of participant group (control vs. expert) and target valence and prime fear relevance. Error bars reflect standard errors of the mean. NFR Pos ⫽ non-fear-relevant prime/positive target, FR Pos ⫽ fear-relevant prime/ positive target; NFR Neg ⫽ non-fear-relevant prime/negative target; FR Neg ⫽ fear-relevant prime/negative target.

claim to like snakes and spiders more than do controls. This difference was found on explicit and implicit measures of evaluation. Control and expert participants responded similarly in the visual search task, showing preferential detection of pictures of fear-

relevant as compared with non-fear-relevant animals. Thus, fearrelevant animals were preferentially attended to regardless of explicit attitudes toward these stimuli. In contrast, the results of the affective priming task indicated that implicit evaluations varied with explicit attitudes, thus implicit and explicit attitudes were

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consistent. Performance on the affective priming task also indicated that dangerousness affected implicit evaluations in experts. Control participants evaluated both dangerous and nondangerous snakes and spiders as more negative than other animals, whereas expert participants evaluated only dangerous but not nondangerous snakes and spiders as more negative than other animals. These results suggest that expert participants identified particular snake and spider exemplars and responded accordingly, differentiating between dangerous and nondangerous snakes and spiders. This distinction was not present in control participants, who lacked the expert knowledge to identify the animals involved. These findings are inconsistent with the idea of an automatic and negative response to fear-relevant stimuli on the basis of an analysis of low-level perceptual features. The current research instead demonstrates a divergence between preferential attention to fearrelevant stimuli and the implicit valence associated with these stimuli. The present results can be incorporated into a nonassociative framework of the processing of fear relevance by proposing that the automatic fear response may be inhibited as a consequence of new learning. The preexisting link between snakes and spiders and fear may have been extinguished in the expert participant group. Nonassociative models propose that there are a set of evolutionarily relevant stimuli, such as snakes and spiders, that most members of a species will show fear for given normal maturation and experience (Poulton & Menzies, 2002). Rachman (2002) proposed that normal maturation also results in learning not to fear certain stimuli or situations. Whereas children often fear the dark or strangers, these fears are generally reduced or absent by adulthood. Given that, in contrast to experts, most people have only minimal exposure to snakes and spiders, the link between these animals and fear may be maintained in the majority of the population. However, expert participants may have learned not to fear these animals, or to inhibit their fear response. Alternatively, the generation of a fear response, or the presence of implicit negative valence associated with a fear-relevant stimulus, may be dependent on whether a fear association exists with the stimulus. In the current research, control participants regarded all snakes and spiders as explicitly negative, whereas the experts did not. These explicit attitudes may reflect on the presence or absence of a fear association with snakes and spiders. This prior fear association may be the prerequisite for the elicitation of a fear response when confronted with these stimuli. This notion is consistent with research on primates reared in captivity who did not display fear of a snake spontaneously, but only after exposure to a vicarious learning episode (see Cook & Mineka, 1989). Expert participants may not have a preexisting fear association with all snakes and spiders, but may have learned to discriminate in the course of repeated exposure. In summary, the current research indicates that there is a dissociation between preferential attentional processing and explicit and implicit evaluation. In the current study, fear-relevant stimuli were preferentially attended to regardless of the participants’ explicit attitudes toward the stimuli. However, the implicit valence of the fear-relevant stimuli varied with explicit attitudes, in that fearrelevant stimuli were only implicitly negative for participants who rated snakes and spiders as negative, that is, the control group. Moreover, expert participants differentiated between dangerous and nondangerous snakes and spiders, with only dangerous snakes

and spiders being implicitly negative for this group. These results are not consistent with the notion that preferential detection of fear-relevant stimuli is accompanied by an automatic and encapsulated fear response. Rather, it appears that detection of fearrelevant stimuli, on the basis of low-level perceptual features, recruits resources for further processing that allows the identification and evaluation of the stimulus. Once the stimulus has been identified, fear may or may not be activated on the basis of an individual’s learning history.

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Received April 4, 2006 Revision received December 6, 2006 Accepted December 12, 2006 䡲