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)     

The detection of fear-relevant stimuli: Are guns noticed as quickly as snakes?

Potentially dangerous stimuli are important contenders for the capture of visual-spatial attention, and it has been suggested that an evolved fear module is preferentially activated by stimuli that are fear relevant in a phylogenetic sense (e.g., snakes, spiders, angry faces). In this study, a visual search task was used to test this hypothesis by directly contrasting phylogenetically (snakes) and ontogenetically (guns) fear-relevant stimuli. Results showed that the modern threat was detected as efficiently as the more ancient threat. Thus, both guns and snakes attracted attention more effectively than neutral stimuli (flowers, mushrooms, and toasters). These results support a threat superiority effect but not one that is preferentially accessed by threat-related stimuli of phylogenetic origin. The results are consistent with the view that faster detection of threat in visual search tasks may be more accurately characterized as relevance superiority effects rather than as threat superiority effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attentional bias to pictures of fear-relevant animals in a dot probe task.

Attentional bias to fear-relevant animals was assessed in 69 participants not preselected on self-reported anxiety with the use of a dot probe task showing pictures of snakes, spiders, mushrooms, and flowers. Probes that replaced the fear-relevant stimuli (snakes and spiders) were found faster than probes that replaced the non-fear-relevant stimuli, indicating an attentional bias in the entire sample. The bias was not correlated with self-reported state or trait anxiety or with general fearfulness. Participants reporting higher levels of spider fear showed an enhanced bias to spiders, but the bias remained significant in low scorers. The bias to snake pictures was not related to snake fear and was significant in high and low scorers. These results indicate preferential processing of fear-relevant stimuli in an unselected sample. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Emotional conditioning to masked stimuli: Expectancies for aversive outcomes following nonrecognized fear-relevant stimuli.

The role of conscious awareness in human Pavlovian conditioning was examined in 2 experiments using masked fear-relevant (snakes and spiders; Experiments 1 and 2) and fear-irrelevant (flowers and mushrooms; Experiment 1) pictures as conditioned stimuli, a mild electric shock as the unconditioned stimulus, and skin conductance responses as the primary dependent variable. The conditioned stimuli were presented briefly (30 ms) and were effectively masked by an immediately following masking stimulus. Experiment 1 demonstrated nonconscious conditioning to fear-relevant but not to fear-irrelevant stimuli. Even though the participants could not recognize the stimuli in Experiment 2, they differentiated between masked stimuli predicting and not predicting shocks in expectancy ratings. However, expectancy ratings were not related to the conditioned autonomic response. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Emotional Conditioning to Masked Stimuli and Modulation of Visuospatial Attention.

Two studies investigated the effects of conditioning to masked stimuli on visuospatial attention. During the conditioning phase, masked snakes and spiders were paired with a burst of white noise, or paired with an innocuous tone, in the conditioned stimulus (CS)+ and CS- conditions, respectively. Attentional allocation to the CSs was then assessed with a visual probe task, in which the CSs were presented unmasked (Experiment 1) or both unmasked and masked (Experiment 2), together with fear-irrelevant control stimuli (flowers and mushrooms). In Experiment 1, participants preferentially allocated attention to CS+ relative to control stimuli. Experiment 2 suggested that this attentional bias depended on the perceived aversiveness of the unconditioned stimulus and did not require conscious recognition of the CSs during both acquisition and expression. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Selective associations in the observational conditioning of fear in rhesus monkeys.

Three experiments explored the issue of selective associations in the observational conditioning of fear. Experiment 1 results indicated that observer rhesus monkeys acquired a fear of snakes through watching videotapes of model monkeys behaving fearfully with snakes. In Experiment 2, observers watched edited videotapes that showed models reacting either fearfully to toy snakes and nonfearfully to artificial flowers (SN+/FL–) or vice versa (FL+/SN–). SN+/FL– observers acquired a fear of snakes but not of flowers; FL+/SN– observers did not acquire a fear of either stimulus. In Experiment 3, monkeys solved complex appetitive discriminative (PAN) problems at comparable rates regardless of whether the discriminative stimuli were the videotaped snake or the flower stimuli used in Experiment 2. Thus, monkeys appear to selectively associate snakes with fear. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the automatic nature of phobic fear: Conditioned electrodermal responses to masked fear-relevant stimuli.

Normal Ss (n?=?64) were exposed either to pictures of snakes and spiders or to pictures of flowers and mushrooms in a differential conditioning paradigm in which one of the pictures signaled an electric shock. In a subsequent extinction series, these stimuli were presented backwardly masked by another stimulus for half of the Ss, whereas the other half received nonmasked extinction. In support of a hypothesis that suggests that nonconscious information-processing mechanisms are sufficient to activate responses to fear-relevant stimuli, differential skin conductance response to masked conditioning and control stimuli was obvious only for Ss conditioned to fear-relevant stimuli. These results were replicated in a 2nd experiment (n?=?32), which also demonstrated that the effect was unaffected by which visual half-field was used for stimulus presentation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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 time it takes bilinguals and monolinguals to draw pictures and write words.

In 4 experiments, picture-word translation was studied in Spanish-English bilinguals and English monolinguals. In Experiment 1, bilinguals drew pictures or wrote English or Spanish words for picture or English or Spanish word stimuli. Equivalent increases in production onset latency for cross-language/modality translation were found. In Experiment 2, bilinguals and monolinguals drew pictures or wrote English words for picture or English word stimuli. Cross-modality translation equivalence was replicated, though bilinguals were slower than monolinguals overall. In Experiment 3, bilinguals and monolinguals were equivalent when they drew or wrote names from pictures as blocked tasks. In Experiment 4, bilinguals replicated Experiment 1 but were faster for blocked than mixed tasks, indicating that stimulus-processing uncertainty slows them. Results support a revised concept mediation model, with equivalent semantic access for pictures and words for bilinguals and monolinguals (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stimulus control of antipredator behavior in newborn and juvenile garter snakes (Thamnophis).

Used neonate and juvenile garter snakes (Thamnophis sirtalis, T. melanogaster, and T. butleri) to investigate the role of visual stimuli in mediating antipredator behaviors and to examine the validity of techniques used to assess defensive responses. Experiment 1 demonstrated that a human hand and a model predator were more effective than other stimuli in eliciting defensive responses in neonates with no prior experience with threatening stimuli. Experiment 2 showed that yearlings responded similarly to a realistic predator model and a human hand. Experiment 3 showed that the level of antipredator behaviors was affected by stimulus size. Experiment 4 indicated that the same snakes gave similar quantitative results when tested by different experimenters with the human hand. The final study demonstrated that stimulus movement influenced defensive responses in some species but not others and found litter and experiential effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Scared by you: Modulation of bodily-self by emotional body-postures in autism.

Objective: Bodily self-recognition is one aspect of our ability to distinguish between self and others and is central to effective socialization. Here we explored the influence of emotional body postures on bodily self-processing in typically developing (TD) as well as in high-functioning ASD children. Method: Subjects' bodies were photographed while expressing endogenously- (self-generated, Experiment 1) or exogenously-driven body emotions (imitated upon request, Experiment 2). Postures conveying positive (happiness), negative (fearful) and neutral valences were used. These pictures served as stimuli in a visual matching-to-sample task with self and others' body-images. Results: A similar self-versus-others advantage was found in TD and in ASD children, since participants were faster with stimuli representing their own than others' body. This “self-advantage” was modulated by self-expressed emotional body postures being present with pictures of happy and neutral, but not fearful body images. This modulation was stronger when emotional postures were endogenously rather than exogenously driven. Moreover, faster responses were observed for others' fearful rather than happy or neutral body images in both groups. Conclusions: The bodily self-advantage is a low-level function present in typically developing (TD) and in high-functioning ASD children. Body postures, especially when they are endogenously generated, modulate the self and others' body processing. The advantage for processing others' fearful, comparing to others' happy and neutral, body postures may have played a crucial evolutionary role for species survival. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Emotion drives attention: Detecting the snake in the grass.

Participants searched for discrepant fear-relevant pictures (snakes or spiders) in grid-pattern arrays of fear-irrelevant pictures belonging to the same category (flowers or mushrooms) and vice versa. Fear-relevant pictures were found more quickly than fear-irrelevant ones. Fear-relevant, but not fear-irrelevant, search was unaffected by the location of the target in the display and by the number of distractors, which suggests parallel search for fear-relevant targets and serial search for fear-irrelevant targets. Participants specifically fearful of snakes but not spiders (or vice versa) showed facilitated search for the feared objects but did not differ from controls in search for nonfeared fear-relevant or fear-irrelevant, targets. Thus, evolutionary relevant threatening stimuli were effective in capturing attention, and this effect was further facilitated if the stimulus was emotionally provocative. (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)     

Memory for picture fragments in monkeys and humans.

Utilized a delayed matching-to-sample procedure to study recognition memory for picture fragments in 33 undergraduates and 3 squirrel monkeys (Saimiri sciureus). Three types of masks varied in the part of the picture they covered, either the center, the periphery, or randomly selected small portions of the picture (noise mask). In Exp I, Ss saw whole sample pictures and had to respond to fragments as comparison pictures. In Exp II, fragments were presented as samples and whole pictures as comparison stimuli. In Exp III, both the samples and comparisons were picture fragments. Recognition accuracy improved in both monkeys and humans as the percentage of the picture exposed increased, and accuracy was lowest with a central mask, intermediate with a noise mask, and highest with a peripheral mask. Data may be used to argue for similar content of visual memories in monkeys and humans. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conceptual behavior in pigeons: Categories, subcategories, and pseudocategories.

In 3 experiments with a total of 16 Ss, we explored how pigeons learn to classify diverse pictures of cats, flowers, cars, and chairs and later how they accurately categorize brand-new pictures from these classes. Using a 4-key forced-choice procedure, Ss in Exp 1 discriminated individual examples within each of the categories from one another (subcategory training); nevertheless, errors were disproportionately conceptual in nature, with Ss more likely to confuse examples within a given category than between different categories. Ss in Exp 2 trained to classify pictures into human language categories (category training) learned far faster and more completely than Ss trained to sort the same pictures into totally arbitrary groupings (pseudocategory training). Finally, in Exp 3, category-trained and subcategory-trained Ss were tested on normally oriented pictures, on left–right reversals, and on top–bottom reversals. Subcategory-trained Ss responded less accurately on both kinds of reversed pictures and less accurately on top–bottom than on left–right reversals; category-trained Ss were less affected by both types of picture reversals, only top–bottom reversals decrementing their performance. Results suggest that many words in our language denote clusters of related visual stimuli, which pigeons also see as highly similar. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stimulus intensity modulates associative and nonassociative responding in preweanling rats

The purpose of the present study was to determine whether preweanling rats respond differentially to the intensity and energy source of a stimulus. Previous studies have suggested that infants process compound stimuli based on net stimulus intensity regardless of the energy source of the compound's elements, but more direct tests have been needed of the infant's response to the stimulus attributes of intensity and energy source. This response was tested for auditory and visual stimuli that had been equated (Experiment 1) in terms of perceived intensity (low and high). Intensity level and energy source of the stimuli were varied independently within nonassociative (Experiment 2) and associative (Experiment 3) procedures. The overall results indicate that stimuli of a low-perceived intensity were processed in terms of their intensity, whereas high-intensity stimuli were processed on the basis of energy source. These results are relevant to contemporary issues of cognitive development in humans and animals.     

Conditioned discrimination of airborne odorants by garter snakes (Thamnophis radis and T. sirtalis sirtalis).

For snakes, the nasal chemical senses are critical in intraspecific communication and prey recognition. Although it is known that garter snakes can respond differentially to airborne odorants, no previous study has demonstrated that snakes can learn a task with airborne odors as discriminative stimuli. In Experiment 1, 7 plains garter snakes (Thamnophis radix) were trained in a two-choice apparatus to move into a compartment containing lemon-scented chips for a food reward. All 7 snakes improved performance when the first 10 and last 10 trials of the 100 trials of conditioning were compared. Four of the snakes were subsequently trained to move away from the scented compartment into the unscented compartment. The 4 snakes rapidly learned this reversal. In Experiment 2, 7 common garter snakes (T. sirtalis sirtalis) were trained to traverse a two-choice maze with the presence or absence of amyl acetate odor as the conditioned stimulus. The snakes were pretested for odor versus nonodor preference and were trained to go to the initially nonpreferred stimulus. Of the 7 snakes, 5 achieved a predetermined criterion (two training sessions with cumulative correct responding above the .05 confidence level) within 85 trials. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Detection of Grouped and Ungrouped Parts in Visual Patterns by Tufted Capuchin Monkeys (Cebus apella) and Humans (Homo sapiens).

The authors investigated perceptual grouping in capuchin monkeys (Cebus apella) and humans (Homo sapiens). In Experiment 1, 6 monkeys received a visual pattern as the sample and had to identify the comparison stimulus featuring some of its parts. Performance was better for ungrouped parts than for grouped parts. In Experiment 2, the sample featured the parts, and the comparison stimuli, the complex figures: The advantage for ungrouped elements disappeared. In Experiment 3, in which new stimuli were introduced, the results of the previous experiments were replicated. In Experiment 4, 128 humans were presented with the same tasks and stimuli used with monkeys. Their accuracy was higher for grouped parts. Results suggest that human and nonhuman primates use different modes of analyzing multicomponent patterns. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Observational conditioning of fear to fear-relevant versus fear-irrelevant stimuli in rhesus monkeys.

Two experiments examined whether superior observational conditioning of fear occurs in observer rhesus monkeys that watch model monkeys exhibit an intense fear of fear-relevant, as compared with fear-irrelevant, stimuli. In both experiments, videotapes of model monkeys behaving fearfully were spliced so that it appeared that the models were reacting fearfully either to fear-relevant stimuli (toy snakes or a toy crocodile), or to fear-irrelevant stimuli (flowers or a toy rabbit). Observer groups watched one of four kinds of videotapes for 12 sessions. Results indicated that observers acquired a fear of fear-relevant stimuli (toy snakes and toy crocodile), but not of fear-irrelevant stimuli (flowers and toy rabbit). Implications of the present results for the preparedness theory of phobias are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Activating representations in permanent memory: different benefits for pictures and words

Previous research has suggested that pictures have privileged access to semantic memory (W. R. Glaser, 1992), but J. Theios and P. C. Amrhein (1989b) argued that prior studies inappropriately used large pictures and small words. In Experiment 1, participants categorized pictures reliably faster than words, even when both types of items were of optimal perceptual size. In Experiment 2, a poststimulus flashmask and judgments about internal features did not eliminate picture superiority, indicating that it was not due to differences in early visual processing or analysis of visible features. In Experiment 3, when participants made judgments about whether items were related, latencies were reliably faster for categorically related pictures than for words, but there was no picture advantage for noncategorically associated items. Results indicate that pictures have privileged access to semantic memory for categories, but that neither pictures nor words seem to have privileged access to noncategorical associations.