"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)     

Effects of visual alcohol cues on alcoholics' autonomic arousal.

Determined whether visual alcohol cues alone (slides showing drinking environments and alcohol beverage bottles) were sufficient to elicit autonomic arousal. 82 male alcoholics (aged 25–64 yrs) were shown alcohol-related or control slides while electrodermal responses were being recorded. Each slide was presented for 4 sec and interstimulus intervals varied between 20 and 30 sec. The frequency of skin conductance responses (SCRs) and the amplitude of the first SCR to each picture presentation were greater to alcohol slides than to control slides. The Ss showed slower habituation to alcohol-related slides as compared with control slides. Pictures of hard liquor yielded higher SCR amplitudes than did pictures of beer. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pigeon visual memory capacity.

Four experiments examined visual memory capacity in 13 White Carneaux pigeons. In Exp I, Ss learned to discriminate between 80 pairs of random shapes. Memory for 40 of those pairs was only slightly poorer following 490 days without exposure. In Exp II, 80 pairs of photographic slides were learned; 629 days without exposure did not significantly disrupt memory. In Exp III, 160 pairs of slides were learned; 731 days without exposure did not significantly disrupt memory. In the final experiment, Ss learned to respond appropriately to 40 pairs of slides in the normal orientation and to respond in the opposite way when the slides were left–right reversed. After an interval of 751 days, there was a transient disruption in discrimination. These experiments demonstrate that pigeons have a heretofore unsuspected capacity with regard to both breadth and stability of memory for abstract stimuli and pictures. (39 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Phobias and preparedness: Phobic versus neutral pictures as conditioned stimuli for human autonomic responses.

Exposed 64 undergraduates to pictures of phobic (snakes) and supposedly neutral (human faces or houses) objects as conditioned stimuli (CSs) in a classical conditioning experiment with shock as the unconditioned stimulus (UCS) and skin conductance responses as the dependent variable. One group was shocked on the phobic and another on one of the neutral sets of pictures. During 10 acquisition trials both groups showed equal conditioning on CS and pre-UCS responses. During extinction, however, there were lasting conditioning effects in CS and, to a lesser extent, post-UCS responses to phobic but not to neutral stimuli. Instructions that no more shocks would be given seemed ineffective in modifying CS, but not post-UCS, responses. It is concluded that the present experimental situation may serve as an experimental analog of phobias. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Facial expressions as conditioned stimuli for electrodermal responses: A case of "preparedness"?

Converging data suggest that human facial behavior has an evolutionary basis. Combining these data with M. E. Seligman's (1970) preparedness theory, it was predicted that facial expressions of anger should be more readily associated with aversive events than should expressions of happiness. Two experiments involving differential electrodermal conditioning to pictures of faces, with electric shock as the unconditioned stimulus, were performed. In the 1st experiment, 32 undergraduates were exposed to 2 pictures of the same person, 1 with an angry and 1 with a happy expression. For half of the Ss, the shock followed the angry face, and for the other half, it followed the happy face. In the 2nd experiment, 3 groups of 48 undergraduates differentiated between pictures of male and female faces, both showing angry, neutral, and happy expressions. Responses to angry CSs showed significant resistance to extinction in both experiments, with a larger effect in Exp II. Responses to happy or neutral CSs, on the other hand, extinguished immediately when the shock was withheld. Results are related to conditioning to phobic stimuli and to the preparedness theory. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

One-Trial Learning and Superior Resistance to Extinction of Autonomic Responses Conditioned to Potentially Phobic Stimuli.

Human subjects were exposed to pictures of potentially phobic (snakes) and supposedly neutral (houses) objects as conditioned stimuli (CSs) in a Pavlovian conditioning experiment with shock as unconditioned stimulus (US), and skin conductance and finger pulse volume as dependent variables. The skin conductance responses conditioned to phobic stimuli were acquired after one CS-US pairing, and showed practically no extinction, whereas the responses to neutral stimuli showed very little resistance to extinction after both 1 and 5 reinforcements. The superior resistance to extinction of the phobic condition was interpreted to be a specific associative effect. In general, the skin conductance acquisition data showed tendencies similar to those during extinction. For finger pulse volume responses, however, there were very weak conditioning effects, and no effect of stimulus. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Time delay and similarity effects in facial recognition.

Conducted 4 experiments to investigate the ability to 232 undergraduates to recognize a target person, whom they had previously seen in slides or a film, in a test series of pictures. Exp I, which manipulated time delay between seeing the target and starting the test series (from 4 min to 1 wk), demonstrated that delay had no effect on recognition performance. The other 3 studies manipulated similarity between the target person and the decoy pictures preceding the target in the search series. The greater the target-decoy similarity, the poorer the recognition performance. A significant Target Position * Similarity interaction indicated the presence of a larger performance decrement due to position when similarity level was high. (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)     

Sex differences and self-report of fear: A psychophysiological assessment.

Hypothesized that, because of differential social learning, females would report fear of spiders more frequently than males would but that males selected for equal self-report of fear would show greater autonomic responsivity than females to slides of spiders. Four groups of 10 undergraduates each (male and female fearful and nonfearful) were assembled. They were told to wait quietly for 10 min, after which they would see slides of tarantulas. Skin conductance level was measured during the anticipatory period and in response to each of the slides. Results confirm the hypothesis that more women would report fear than men but failed to confirm the hypothesis that there would be differential autonomic responding. Fearful Ss, irrespective of sex, showed prolonged autonomic arousal during the entire anticipatory period, whereas nonfearful Ss showed increasing autonomic arousal as the time for the 1st slide presentation approached. This finding is discussed in terms of coping theory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Automatic attention does not equal automatic fear: Preferential attention without implicit valence.

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 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. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neonatal habituation and dishabituation to tactile stimulation during sleep.

Two experiments examined habituation and dishabituation of behavioral responding to repeated presentations of a tactile stimulus (brush stroke) in 48 newborns during the 1st epoch of active-quiet sleep following a feeding. Exp I demonstrated habituation to a repeatedly presented brush stroke to the ear but failed to demonstrate dishabituation (i.e., response recovery) to the original brush stroke following an intense auditory stimulus (86 dB rattle sound). A post hoc control group showed that the intense auditory stimulus had suppressed subsequent responding to the tactile stimulus. Exp II replicated the habituation phase of Exp I and demonstrated response recovery to stimulation at a novel tactile site and to an auditory probe. Results indicate that the habituation paradigm used in infancy research could be successfully extended to the tactile modality. It is also suggested that prior auditory stimulation, but not prior tactile stimulation, might direct attention away from a subsequently presented tactile stimulus. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Habituation of the shortening reflex in the medicinal leech.

Conducted 3 experiments in which the shortening reflex was elicited in 46 food-sated leeches (Hirudo medicinalis) by light flashes delivered at 20-sec intervals over a 40-trial session. In Exp I, the reflex was enhanced if Ss were stored at 5-7° C rather than 20° C. Short-term (within sessions) habituation was readily observed. In Exp II, dishabituation could be produced by a single electric shock at Trial 30. However, in Exp III, the shock also enhanced responding when delivered before Trial 1 (sensitization). No long-term (between-sessions) habituation occurred over 6 consecutive days of testing in Exp I; on the contrary, responding gradually increased. It is suggested that the simplicity of these short-term processes in leeches makes them particularly suitable for electrophysiological investigations into the neural basis of habituation and sensitization. (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Recognizing masked threat: Fear betrays, but disgust you can trust.

If emotions guide consciousness, people may recognize degraded objects in center view more accurately if they either fear the objects or are disgusted by them. Therefore, we studied whether recognition of spiders and snakes correlates with individual differences in spider fear, snake fear, and disgust sensitivity. Female students performed a recognition task with pictures of spiders, snakes, flowers, and mushrooms as well as blanks. Pictures were backward masked to reduce picture visibility. Signal detection analyses showed that recognition of spiders and snakes was correlated with disgust sensitivity but not with fear of spiders or snakes. Further, spider fear correlated with the tendency to misinterpret blanks as threatening (response bias). These findings suggest that effects on recognition and response biases to emotional pictures vary for different emotions and emotional traits. Whereas fear may induce response biases, disgust may facilitate recognition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential sensitization, retention, and generalization of habituation in two response systems in the blowfly (Calliphora vomitoira).

Conducted 3 experiments with 95 blowflies to elicit a cardiac disturbance and a motor response by the same moving visual stimulus. In Exp I, the habituation of these responses developed at an equal rate during stimulus repetition. After a rest period, whereas habituation of motor responses was completely retained, a substantial recovery of cardiac responses was observed. The use of distributed trials in Exp II helped to dissociate the influence of sensitization and habituation processes on the behavioral outcome. Habituation of motor responses, in addition to a longer retention, appeared to be more easily generalized after a spatial displacement of the stimulus in Exp III. Data support the hypothesis that habituation processes develop independently in different response systems, even if they have the same sensory input. The faster reversibility of habituation of cardiac responses is discussed, with reference to a preparatory function for locomotor behavior. (41 ref) (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)     

Modeling processes in the acquisition of fears: Vicarious electrodermal conditioning to fear-relevant stimuli.

Describes an experiment with 72 university students in which fear-relevant (snakes, spiders, and rats) and fear-irrelevant (flowers, mushrooms, and berries) pictures were compared as conditioned and instigating stimuli in a vicarious classical conditioning paradigm with skin conductance responses as the dependent variable. A female confederate model and an S watched the pictures side by side. After a few stimulus presentations, the experimenter (E) interrupted to investigate alleged overreactions of the model to one of the stimulus classes. The model then vividly described a phobia for this object, which was to serve as a vicarious instigating stimulus. The experiment continued for a few conditioning trials, and then the E announced that the disturbing stimulus would be omitted before the 2nd part of the experiment. There was no effect of stimulus content on vicariously instigated responses, although significant overall instigation was observed. However, the responses to the stimulus that was paired with the model's phobic stimulus, that is, the vicariously conditioned responses, failed to extinguish during the 2nd part of the experiment when it was fear-relevant but extinguished immediately when it was fear-irrelevant. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

L'apprentissage "preparé" de la peur dans le conditionnement de réponses physiologiques.

Conducted a study aimed at reproducing "prepared" learning effects with additional controls and at verifying M. E. Seligman's (1971) theory predictions regarding phobias and preparedness by integrating 2 physiologic responses, electrodermal and cardiac. Human subjects: 80 normal male Canadian adults (aged 18–32 yrs). Electrodermal and cardiac responses provoked by 4 categories of visual stimuli were compared: prepared (i.e., snakes, spiders); nonprepared (i.e., dental equipment, syringes); unfamiliar neutral stimuli (i.e., cells and abstract arts); and familiar neutral stimuli (i.e., flowers and mushrooms). Ss saw 8 slides at the familiarization stage, 32 slides at the acquisition stage, and 32 slides at the extinction stage. The latent inhibition phenomenon was controlled, and the effect of cognitive arguments on responses was assessed. An electric shock served as an unconditioned stimulus/stimuli (UCS). Repeated-measures analyses of variance were performed. (English abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fear-relevant selective associations and covariation bias.

Three experiments used an illusory correlation paradigm to assess the effects of fear on the perception of the covariation between fear-relevant stimuli and shock. In Exp 1, high- and low-fear women were exposed to 72 trials during each of which a fear-relevant (snake or spider) or fear-irrelevant (mushroom and flower) slide was followed by a shock, a tone, or nothing. Although the relation between slide types and outcomes was random, high-fear subjects markedly overestimated the contingency between feared slides and shock. Exp 2 showed that this bias was due to the aversive, rather than more generally salient, features of shock. Low-fear subjects demonstrated biases equivalent to those of high-fear subjects only when the base rate of shock was increased from 33 to 50% in Exp 3. It is concluded that fear may be linked to biases that serve to confirm fear. The relevance of the present findings to preparedness theory is also discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Categorical discrimination and generalization in pigeons: All negative stimuli are not created equal.

Three experiments investigated categorical discrimination and generalization in pigeons. Multiple FI-extinction training was conducted with a pool of 48 different negative discriminative stimuli (12 slides each of people, flowers, cars, and chairs). The most errors were committed to negative stimuli (S–s) from the same category as the 12 positive stimulus (S+) slides. Such categorical generalization was stronger when the 12 S+s entailed 1 copy of 12 different slides (Exp 2) than when the S+s entailed 12 copies of 1 slide (Exp 1). In addition, reliable but incomplete loss of inhibitory control was observed to novel stimuli chosen from the same category as the S– slides (Exp 3). These results are consistent with perceptual theories of categorical coherence, according to which preexisting similarities among stimuli chiefly determine the acquisition and application of categories. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Studies of concept formation by stumptailed monkeys: Concepts humans, monkeys, and letter A..

Natural concepts were studied in 3 of 4 experiments with 4 stumptailed monkeys, using a series of photographic slides. The concept of humans was studied in Exp I, using scenes with or without one or more humans present, and the concept of monkeys was studied in Exp II, using scenes with one or more monkeys and scenes with other types of animals. In both experiments, Ss were trained on 1 set of slides using a conditional spatial discrimination task and tested for transfer to a new set. All Ss tested showed positive transfer, performing at a higher level with new slides initially than they had during original learning, though well below the level reached by the end of original learning. The initial transfer could not be explained by learning of individual slides, though such learning was clearly a strong factor in the overall performance. Performance was better when humans were a prominent part of the scene. In Exp III, the discrimination task was changed to go/no-go. There was some improvement in discrimination but not in transfer. In Exp IV, Ss were trained to discriminate the letter A from the numeral 2 in a variety of typefaces, and they transferred the discrimination at a high level to a set of these stimuli in new typefaces. Results are consistent with a concept interpretation. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)