Respiratory sinus arrhythmia in response to fear-relevant and fear-irrelevant stimuli

Heart period variability and heart rate were studied in 15 women and 15 men while they were viewing negatively (snakes/spiders), neutrally (scenic views), and positively (cats and kittens/puppies and dogs) valenced films. Time-frequency analyses of the heart period variability power spectrum in the high frequency region (0.12-0.4 Hz), reflecting respiratory sinus arrhythmia (RSA), were carried out during 5 minutes in each condition. The main finding showed that RSA-magnitude (high frequency power) was inversely related to emotional valence: lowest magnitudes were found in response to positive films, and highest magnitude to negative films. The findings were interpreted as reflecting motor or behavioral inhibition, and increased attention to negatively valenced, stimuli.     

Facial reactions to fear-relevant stimuli for subjects high and low in specific fear

This study was performed to investigate whether subjects high and low in fear of snakes react with different facial electromyographic (EMG) responses when exposed to snakes. Two groups of subjects were exposed to slides of snakes or flowers. After the experiment they rated their fear of snakes on a questionnaire and based on these ratings they were divided into high and low fear groups. Facial EMG was measured from the corrugator and zygomatic muscle regions. As predicted the high fear group reacted with a facial response interpretable as a negative emotional reaction whereas the low fear group did not. This difference was specific to snakes because high and low groups did not differ in responses to slides of flowers. The results are consistent with the proposition that facial EMG technique is a sensitive tool to distinguish reactions between subjects high and low in specific fears.     

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.     

The role of fear-relevant stimuli in visual search: a comparison of phylogenetic and ontogenetic stimuli

It has been argued that phylogenetic fear-relevant stimuli elicit preattentive capture of attention. To distinguish between fear relevance and time of appearance in evolutionary history, the authors compare phylogenetic and ontogenetic fear-relevant and fear-irrelevant stimuli in a visual search task. The authors found no evidence for a special role of phylogenetic fear-relevant stimuli; it seems that fear relevance in general is more important than is the evolutionary age. The pattern of results indicates that attention toward threatening stimuli is mainly affected by a late component that prolongs the disengagement of attention.     

Detecting the snake in the grass: attention to fear-relevant stimuli by adults and young children

Snakes are among the most common targets of fears and phobias. In visual detection tasks, adults detect their presence more rapidly than the presence of other kinds of visual stimuli. We report evidence that very young children share this attentional bias. In three experiments, preschool children and adults were asked to find a single target picture among an array of eight distractors. Both the children and the adults detected snakes more rapidly than three types of nonthreatening stimuli (flowers, frogs, and caterpillars). These results provide the first evidence of enhanced visual detection of evolutionarily relevant threat stimuli in young children.     

Skin conductance response conditioning with CS intensities equal to and greater than UCS intensity

With .2-sec bursts of white noise as both conditioned stimulus (CS) and unconditioned stimulus (UCS), conditioning of first-interval skin conductance responses was obtained when the intensity of the CS equaled and exceeded that of the UCS. There was no evidence that second-interval response conditioning occurred. Nonspecific response frequencies were also affected by the variations in stimulus intensity, this raising some question about typical controls employed in SCR conditioning. There was some evidence that second interval responses were suppressed by the intense CS values. It was concluded that the existence of simple conditioning with a CS/UCS intensity ratio equal to or greater than unity was contrary to the Pavlovian proposition that a CS must be biologically less salient than the UCS in order for conditioning to occur. It was noted, however, that the suppression of second-interval responses might indicate that anticipatory CRs which are not confounded with orienting reflexes are prevented from exhibiting a conditioning effect when a high CS/UCS intensity ratio is employed.     

The influence of animal fear on attentional capture by fear-relevant animal stimuli in children

The present study demonstrated that pictures of fear-relevant animals, snakes and spiders, presented among backgrounds of other animal stimuli captured attention and interfered in the detection of a neutral target to the same extent in a large sample of unselected children (N=81). Moreover, detection of a neutral target animal was slowed more in the presence of a feared fear-relevant distracter, e.g., a snake for snake fearful children, than in the presence of a not feared fear-relevant distracter, e.g., a spider for snake fearful children. These results indicate attentional capture by phylogenetically fear-relevant animal stimuli in children and the selective enhancement of this effect by fear of these animals. These findings are consistent with current models of preferential processing of phylogenetically prepared threat stimuli and with cognitive models of anxiety that propose an enhancing effect of fear in the processing of fear-related stimuli.     

Double response to Stroop stimuli.

To reexamine Klein's 1964 findings we carried out two experiments on the double response made to Stroop stimuli. In Exp. 1 incongruent color-word stimuli were presented on a CRT online with a microcomputer. A color-word card was used in Exp. 2. Subjects were asked to read words before naming colors or, conversely, to name colors before reading words. An analysis of variance (the task x the type of task) was performed on response times in both experiments. Two main effects and interactions were nonsignificant. Some subjects made an error-like reverse-order response on the double-response task. The present findings do not support Klein's findings or the competition explanation of the Stroop effect.     

Developmental changes in response preparation to visual stimuli

We examined how preparation to respond changes with age. Subjects from four age groups (5- to 7-, 8- to 11-, 12- to 17-, and 18- to 24-yr.-olds) were given a simple visual RT task with foreperiod duration varied between 300 and 2000 msec. Analysis showed that in addition to the expected effects of age and foreperiod, there were qualitative differences between the performance of adults and children: 5- to 7-yr.-olds reacted quickest after a foreperiod shorter than that required by adults to perform best. Conversely, preadolescents' optimal foreperiod was relatively longer than that of either older or younger subjects. In addition, the youngest subjects showed an inability to maintain preparation as efficiently as older subjects. Implications for the development of response preparation are discussed.     

Culture and sensory response to visual stimuli

This study investigated the influence of culture on people's sensory responses, such as smell, taste, sound and touch to visual stimuli. The sensory feelings of university students from four countries (Japan, South Korea, Britain and France) to six images were evaluated. The images combined real and abstract objects and were presented on a notebook computer. Overall, 280 participants (144 men and 136 women; n = 70/country) were included in the statistical analysis. The chi‐square independence analysis showed differences and similarities in the sensory responses across countries. Most differences were detected in smell and taste, whereas few variations were observed for sound responses. Large variations in the response were observed for the abstract coral and butterfly images, but few differences were detected in response to the real leaf image. These variations in response were mostly found in the British and Japanese participants.     

Skin conductance responses as predictor of emotional responses to stressful life events

Preferential preattentive processing towards threat has been proposed to play a casual role in the development of anxiety, mainly because it reliably predicts emotional responding to stressful events. However, in the investigation of the predictive value of preferential preattentive processing towards threat, the emotional Stroop task has exclusively being used. This study was designed to prospectively investigate the predictive value of skin conductance reactivity in response to masked (i.e., preattentively perceived) threatening pictures on emotional responding following stressful life events. To collect skin conductance data, the picture perception task was administered to 136 police recruits due to enroll into active duty within 2-4 months. To assess psychological distress following emotionally stressful life events, the impact of event scale were administered approximately 24 months later. Controlling for trait anxiety, analyses indicated that enhanced skin conductance reactivity in response to masked threatening pictures (relative to neutrals) was a strong predictor of emotional responding to stressful life events. This finding support preferential preattentive processing towards threat as a relatively independent factor predictive of emotional responding.     

Fear and the amygdala: manipulation of awareness generates differential cerebral responses to phobic and fear-relevant (but nonfeared) stimuli

Rapid response to danger holds an evolutionary advantage. In this positron emission tomography study, phobics were exposed to masked visual stimuli with timings that either allowed awareness or not of either phobic, fear-relevant (e.g., spiders to snake phobics), or neutral images. When the timing did not permit awareness, the amygdala responded to both phobic and fear-relevant stimuli. With time for more elaborate processing, phobic stimuli resulted in an addition of an affective processing network to the amygdala activity, whereas no activity was found in response to fear-relevant stimuli. Also, right prefrontal areas appeared deactivated, comparing aware phobic and fear-relevant conditions. Thus, a shift from top-down control to an affectively driven system optimized for speed was observed in phobic relative to fear-relevant aware processing.     

Job satisfaction among Swedish soldiers: Applying the Job Characteristics Model to newly recruited military personnel

A professional military organization was introduced in Sweden in 2010. This means that the Swedish Armed Forces (SAF) need to attract and employ soldiers, and to retain them within the organization. This scenario creates new types of challenges in manning the organization. The transition to an all-volunteer force puts job satisfaction in focus in order to retain personnel. This cross-sectional study of the relations between working conditions and job involvement among 300 recently employed soldiers showed that the dimensions of the Job Characteristics Model related significantly to job satisfaction and work motivation and (negatively) to turnover intentions from the SAF. The results further showed that all the critical psychological states contributed independently to the variance in the outcome variables.     

Overselective response to social stimuli by autistic children

Previous studies have shown that when presented with a complex stimulus input, autistic children typically respond to only one of the elements of the complex. This phenomenon was called stimulus overselectivity (or overselective attention). The present investigation sought to determine if this overselectivity might be a possible basis for the deviant social behavior in autistic children. Autistic and normal children were trained to discriminate between clothed girl and boy doll figures. After the children had acquired this discrimination, the individual clothing components and the heads were systematically interchanged between the figures. Thus, it could be determined which component(s) the children had used to make the discrimination. The autistic children demonstrated stimulus overselectivity in that they formed the discrimination between the boy and girl figures on the basis of only one component or of peculiar combinations of components. For example, one child discriminated the figures on the basis of shoes. In contrast, the normal children responded primarily to the figures' heads but could also respond correctly to other parts. These findings are consistent with previous research on stimulus overselectivity and have implications for understanding the difficulty autistic children show in forming meaningful social relationships.This investigation was supported by U.S. Public Health Service Research Grant 11440 from the National Institute of Mental Health.The authors express their appreciation to James Q. Simmons, Associate Chief, Mental Retardation and Child Mental Health Programs, Neuropsychiatric Institute, University of California, Los Angeles; and Norbert Rieger, Superintendent of Children's Services, Camarillo State Hospital, Camarillo, California. They are also grateful to Robert Koegel and to Thomas Willis for their valuable suggestions and to Meredith Gibbs for her assistance in data collection.