Fear and autonomic arousal.

32 female undergraduates were classified as having high fear (HF) or low fear (LF) of spiders. After reduction of orienting responses to pictures of neutral animals, experimental Ss were shown pictures of a spider, and control Ss were shown pictures of a snake. Using the response to the last neutral stimulus as a base line, HF experimental Ss when 1st shown a spider yielded greater GSRs than other groups. This increase in GSR responding for HF experimental Ss was, for 2 more trials, maintained relative to control Ss. HF experimental Ss also yielded GSRs of greater duration than all other groups when 1st shown the spider stimulus. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Covariation detection in treated and untreated spider phobics.

20 treated and 18 untreated spider phobics were exposed to a series of 72 slides. Three different categories of slides were used: phobia-relevant slides (spiders), alternative fear-relevant slides (weapons), and neutral slides (flowers). Slides were randomly paired with either a shock, a tone, or nothing at all. Despite the absence of a systematic correlation between slides and outcomes, untreated phobics strongly overestimated the covariation between spider slides and shock. Treated phobics did not show a covariation bias, suggesting that such bias can be modulated by the behavioral treatment. In addition, untreated Ss were more confident about their contingency estimates than were treated Ss. The present results fit with earlier studies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Contribution of bottom-up and top-down motion processes to perceived position.

Perceived position depends on many factors, including motion present in a visual scene. Convincing evidence shows that high-level motion perception-which is driven by top-down processes such as attentional tracking or inferred motion-can influence the perceived position of an object. Is high-level motion sufficient to influence perceived position, and is attention to or awareness of motion direction necessary to displace objects' perceived positions? Consistent with previous reports, the first experiment revealed that the perception of motion, even when no physical motion was present, was sufficient to shift perceived position. A second experiment showed that when subjects were unable to identify the direction of a physically present motion stimulus, the apparent locations of other objects were still influenced. Thus, motion influences perceived position by at least two distinct processes. The first involves a passive, preattentive mechanism that does not depend on perceptual awareness; the second, a top-down process that depends on the perceptual awareness of motion direction. Each contributes to perceived position, but independently of the other. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of arbitrarily assigned status labels on self-perceptions and social perceptions: The mere position effect.

Tested the theory that social position labels by themselves are sufficient to evoke expectations about the attributes of those associated with the labels. 72 male undergraduates in unstructured triads worked on a group decision-making task and then were assigned to 1 of 3 status positions (supervisor, worker, or neutral-status observer) for a separate activity that was expected to occur 2 wks later. The randomness of the assignment was made obvious to the Ss. Ss' subsequent assessments of the initial interaction revealed that self-perceptions were unaffected by the status labels; Ss perceived themselves as more leaderlike and more responsible for the group product than the other group members; and observers and supervisors rated supervisors as more leaderlike than workers. In contrast, the workers' social perceptions were not influenced by positional labels. The data suggest a relation between the self-perceptions and social perceptions of members of a status hierarchy and indicate when status labels will and will not influence evaluations. (25 ref) (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Motion parallax and children's distance perception.

Studied the effectiveness of motion parallax for relative and absolute distance judgments using 48 2nd, 4th, and 6th graders and college adults. Two targets were viewed either monocularly with a fixed head, monocularly with head movements providing motion parallax, or binocularly with head movements providing motion parallax. Ss adjusted the distance of a comparison rod to match the perceived distance of the target, or simply indicated which was nearer. For absolute judgments, accuracy was not affected by age level of the Ss; however, a developmental decrease in the variability of judgment was observed. There were no grade effects for relative judgments. For both judgments, the addition of motion parallax information increased accuracy. Results indicate that children are capable of registering array velocity information for distance. The ability to register self-movement or to integrate self-movement and array motion in the perception of absolute distance may account for the observed developmental changes. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Interaction of motion and color in the visual pathways

We measured perceived velocity as a function of contrast for luminance and isoluminant sinusoidal gratings, luminance and isoluminant plaids, and second-order, amplitude-modulated, drift-balanced stimuli. For all types of stimuli perceived velocity was contrast-invariant for fast moving patterns at or above 4 deg/sec. For slowly moving stimuli the log of perceived velocity was a linear function of the log of the contrast. The slope of this perceived velocity-vs-contrast line (velocity gain) was relatively shallow for luminance gratings and luminance plaids, but was steep for isoluminant gratings and isoluminant plaids, as well as for drift-balanced stimuli. Independent variation of spatial and temporal frequency showed that these variables, and not velocity alone, determine the velocity gain. Overall, the results indicate that slow moving stimuli defined by chromaticity or by second-order statistics are processed in a different manner from luminance defined stimuli. We propose that there are a number of independent mechanisms processing motion targets and it is the interplay of these mechanisms that is responsible for the final percept.     

Mating behaviour in the cellar spider, Pholcus phalangioides, indicates sperm mixing

In insects and spiders, the pattern of sperm priority is often attributed to the shape of the spermathecae and should entail marked consequences for mating behaviour. Since last-male priority is assumed to occur in haplogyne spiders such as the cellar spider, females of this species are predicted to be more attractive to males shortly before, than shortly after, egg laying and males may guard females after copulation until oviposition. To test these predictions, I individually marked spiders of a natural population and recorded their position and the distance between potential mating partners twice a day over 100 days. The distance between female and male was taken as a measure of the female's attractiveness. The behaviour of cellar spider males was not in accordance with the predictions; females were visited throughout the observation period with no significant increase in attractiveness before egg laying and there was no evidence for mate guarding. However, female attractiveness was correlated with female size, which was correlated with the number of eggs laid. Behaviour and genital morphology suggest sperm mixing occurs in this species. This is discussed in the light of conflicting data on sperm priority. Copyright 1998 The Association for the Study of Animal Behaviour.     

Depth perception in motion parallax and stereokinesis.

Perceived depth in the stereokinetic effect (SKE) illusion and in the monocular derivation of depth from motion parallax were compared. Motion parallax gradients of velocity can be decomposed into 2 components: object- and observer-relative transformations. SKE displays present only the object-relative component. Observers were asked to estimate the magnitude and near–far order of depth in motion parallax and SKE displays. Monocular derivation of depth magnitude from motion parallax is fully accounted for by the perceptual response to the SKE, and observer-relative transformations absent in the SKE are of perceptual utility only as determinants of the near–far signing of perceived sequential depth. The amount of depth and rigidity perceived in motion parallax and SKE displays covaries with the projective size of the stimuli. The monocular derivation of depth from motion is mediated by a perceptual heuristic of which the SKE is symptomatic. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

From fear to love: Individual differences in implicit spider associations.

The Implicit Association Test (IAT) was used to investigate automatic fear associations in fear of spiders. Fear associations toward spiders were measured among spider fearful and nonfearful participants (Experiment 1) as well as among nonfearfuls and spider enthusiasts (Experiment 2). It was shown that the IAT is sensitive to personal automatic fear associations and therefore distinguishes between high-fearful, nonfearful, and enthusiastic participants. Moreover, implicit spider associations measured by the IAT predicted avoidance behavior beyond self-reports. The results of Experiment 2 provide additional support for the argument that implicit spider associations are different from general stereotypes or knowledge about spiders. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pathological changes in yearly protocol liver biopsy specimens from healthy pediatric liver recipients

Fear of spiders, disgust sensitivity, and spiders' disgust-evoking status were assessed in a group of spider phobic girls (n = 22) who applied for treatment, in a group of non-phobic girls (n = 21), and in the parents of both groups of children. The phobic girls were tested both before and after behavioural treatment which consisted of 1.5 hr eye movement desensitization and reprocessing and 1.5 hr exposure in vivo. Findings support the idea that disgust is an important aspect of spider phobia: (a) spider phobic girls exhibited higher levels of disgust sensitivity and considered spiders per se as more disgusting than non-phobic girls; (b) there was a parallel decline of spider fear and spiders' disgust-evoking status as a result of treatment; and (c) spiders' disgust-evoking status was relatively strong in mothers of spider phobic girls. The latter finding may indicate, that the acquisition of spider fear is facilitated by specific parental disgust reactions when confronted with spiders.     

Of snakes and flowers: Does preferential detection of pictures of fear-relevant animals in visual search reflect on fear-relevance?

Previous research in visual search indicates that animal fear-relevant deviants, snakes/spiders, are found faster among non fear-relevant backgrounds, flowers/mushrooms, than vice versa. Moreover, deviant absence was indicated faster among snakes/spiders and detection time for flower/mushroom deviants, but not for snake/spider deviants, increased in larger arrays. The current research indicates that the latter 2 results do not reflect on fear-relevance, but are found only with flower/mushroom controls. These findings may reflect on factors such as background homogeneity, deviant homogeneity, or background-deviant similarity. The current research removes contradictions between previous studies that used animal and social fear-relevant stimuli and indicates that apparent search advantages for fear-relevant deviants seem likely to reflect on delayed attentional disengagement from fear-relevance on control trials. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The maverick effect: Increased communicator credibility as a result of abandoning a career.

Used questionnaire responses to select 200 undergraduates who did not hold extreme opinions on the topics of unidentified flying objects and ecology. Ss were assigned to 1 of 4 groups and heard a communicator deliver messages either for or against 1 of the 2 issues. One-half of the Ss in each of 4 conditions heard a message from a "maverick" who had quit an organization over the issue he was now discussing. The other 1/2 heard a person who was a member of an organization and who delivered a message in line with the official position of that organization. The "mavericks" were perceived as fairer and more trustworthy than the "nonmavericks," but not as more expert. The mavericks' conclusions were perceived as better justified by the facts, and more opinion change was elicited toward their positions, as measured by the percentage of Ss changing and by the pre-post communication position of audiences. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Judging health status: Effects of perceived prevalence and personal relevance.

Investigated whether people's evaluations of the seriousness of a health disorder are influenced by the perceived prevalence and personal relevance of that disorder. As part of a study ostensibly concerned with college students' health characteristics, 60 undergraduates were tested for the presence of a fictitious enzyme deficiency. Ss discovered either that they had the deficiency (deficiency-present Ss) or that they did not have it (deficiency-absent Ss) and were led to believe either that 1 of the 5 people in the laboratory had the deficiency (low-prevalence Ss) or that 4 of them had it (high-prevalence Ss). As predicted, the low-prevalence Ss evaluated the deficiency as more serious than did the high-prevalence Ss. In addition, consistent with the view that personal relevance affects perceptions of health disorders, the deficiency-present Ss evaluated the deficiency as less serious than did the deficiency-absent Ss. The deficiency-present Ss also derogated the validity of the test ostensibly used to diagnose the deficiency compared with other Ss. The deficiency-present Ss requested more information about the deficiency than did the deficiency-absent Ss. (53 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"Unconscious anxiety": Phobic responses to masked stimuli.

Tested the hypothesis that an unconscious preattentive perceptual analysis of phobic stimuli is sufficient to elicit human fear responses. Selected snake- and spider-fearful Ss, as well as normal controls, were exposed to pictures of snakes, spiders, flowers, and mushrooms. A separate forced-choice recognition experiment established backward masking conditions that effectively precluded recognition of experimental stimuli both for fearful and nonfearful Ss. In the main experiment, these conditions were used to compare skin conductance responses (SCRs) to masked and nonmasked phobic and control pictures among fearful and nonfearful Ss. In support of the hypotheses, snake- and spider-fearful Ss showed elevated SCRs to snake and spider pictures as compared with neutral pictures and with responses of the nonfearful Ss under both masking conditions. Ratings of valence, arousal, and dominance indicated that the fearful Ss felt more negative, more aroused, and less dominant in relation to both masked and nonmasked phobic stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceived variability and symbol use: A common language-cognition interface in children and chimpanzees (Pan troglodytes).

Analysis of 2 chimpanzees' conversations with their teacher during a tool-use training task demonstrated that Ss used lexigrams, a humanly devised visual symbol system, selectively to encode perceived variability. Ss generally used their symbols to differentiate alternative possibilities or to represent change or novelty in a situation. In contrast, Ss tended to leave unsaid what was unchanging, repetitive, or the unique possibility in a situation. Perceived variability influenced not only which symbols were selected but also utterance length: A single dimension of variability in a situation led to single-lexigram utterances; multiple dimensions were associated with multilexigram utterances. Results indicate that the absence of formal grammatical structure in chimp language does not imply that utterances beyond 1 word in length are either rote strings or imitations. Ss' tendency to mention the variable while leaving the constant or redundant unsaid was supportive of the position that their use of a humanly devised symbol system is more than a series of CRs. (41 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Snakes and Cats in the Flower Bed: Fast Detection Is Not Specific to Pictures of Fear-Relevant Animals.

The observation that snakes and spiders are found faster among flowers and mushrooms than vice versa and that this search advantage is independent of set size supports the notion that fear-relevant stimuli are processed preferentially in a dedicated fear module. Experiment 1 replicated the faster identification of snakes and spiders but also found a set size effect in a blocked, but not in a mixed-trial, sequence. Experiment 2 failed to find faster identification of snake and spider deviants relative to other animals among flowers and mushrooms and provided evidence for a search advantage for pictures of animals, irrespective of their fear relevance. These findings suggest that results from the present visual search task cannot support the notion of preferential processing of fear relevance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

External validity of laboratory fear assessment: Implications from two case studies.

Exposed 1 snake-phobic woman and 1 spider-phobic woman to a live snake or spider after they received systematic desensitization. In one assessment condition the 2 Ss were asked to approach and handle a caged snake or spider as in the traditional behavioral approach test, whereas in the other condition the Ss were exposed to the uncaged phobic stimuli. Both Ss manifested substantially greater physiological and cognitive distress while looking at the uncaged stimuli from a distance of 30 ft than when actually touching the caged snake or spider. Although both Ss were able to touch the caged snake or spider, they still reported being unable to engage in behaviors that were previously inhibited because of their phobia. Both Ss emphasized the importance of feeling in control when the phobic stimulus was caged but feeling out of control when the phobic stimulus was uncaged. Implications for the external validity of the behavioral approach test are discussed. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The generalization of the effects of agreement and correctness on relative competence mediating conformity.

Presented a social communication task to 215 Canadian high school students (Grades 8-13). Results show that correctness and group agreement interacted with grade level, producing varying degrees of perceived competence relative to a simulated group. For Ss in Grades 8-10 only, the experimental manipulation of relative competence influenced conformity; Ss who were told that they were more competent than the group conformed less than those who were told that they were either less competent than or as competent as the group. Ss who perceived themselves to be more competent than the group also conformed less. Other findings are that: (a) females showed significantly higher conformity, (b) Ss in Grades 11-13 indicated more suspicion and awareness of the possibility of deception, and (c) no differences in conformity existed between suspicious and nonsuspicious Ss. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)