Non-threatening Stimuli Research Articles

What's so scary about needles and knives? Examining the role of experience in threat detection

Snakes and spiders constitute a category of evolutionarily relevant stimuli that were recurrent and widespread threats to survival throughout human evolution. A large body of research has suggests that humans have an inborn bias to detect these stimuli more rapidly than non-threatening stimuli. However, recent research has demonstrated that adults also show rapid detection of modern threat-relevant stimuli, such as knives and syringes. This suggests that experience may also lead to rapid detection of threatening stimuli. The research reported here is an investigation of whether young children have an attentional bias for the detection of two types of modern threat-relevant stimuli—one with which they have experience (syringes) versus one with which they do not (knives). As predicted, the children detected the presence of syringes more quickly than pens, but did not detect knives more quickly than spoons. These results provide strong support for multiple mechanisms in threat detection.

Superior detection of threat‐relevant stimuli in infancy

The ability to quickly detect potential threat is an important survival mechanism for humans and other animals. Past research has established that adults have an attentional bias for the detection of threat-relevant stimuli, including snakes and spiders as well as angry human faces. Recent studies have documented that preschool children also detect the presence of threatening stimuli more quickly than various non-threatening stimuli. Here we report the first evidence that this attentional bias is present even in infancy. In two experiments, 8- to 14-month-old infants responded more rapidly to snakes than to flowers and more rapidly to angry than to happy faces. These data provide the first evidence of enhanced visual detection of threat-relevant stimuli in infants and hence offer especially strong support for the existence of a general bias for the detection of threat in humans.

Generalization of conditioned fear along a dimension of increasing fear intensity.

The present study investigated the extent to which fear generalization in humans is determined by the amount of fear intensity in nonconditioned stimuli relative to a perceptually similar conditioned stimulus. Stimuli consisted of graded emotionally expressive faces of the same identity morphed between neutral and fearful endpoints. Two experimental groups underwent discriminative fear conditioning between a face stimulus of 55% fear intensity (conditioned stimulus, CS+), reinforced with an electric shock, and a second stimulus that was unreinforced (CS-). In Experiment 1 the CS- was a relatively neutral face stimulus, while in Experiment 2 the CS- was the most fear-intense stimulus. Before and following fear conditioning, skin conductance responses (SCR) were recorded to different morph values along the neutral-to-fear dimension. Both experimental groups showed gradients of generalization following fear conditioning that increased with the fear intensity of the stimulus. In Experiment 1 a peak shift in SCRs extended to the most fear-intense stimulus. In contrast, generalization to the most fear-intense stimulus was reduced in Experiment 2, suggesting that discriminative fear learning procedures can attenuate fear generalization. Together, the findings indicate that fear generalization is broadly tuned and sensitive to the amount of fear intensity in nonconditioned stimuli, but that fear generalization can come under stimulus control. These results reveal a novel form of fear generalization in humans that is not merely based on physical similarity to a conditioned exemplar, and may have implications for understanding generalization processes in anxiety disorders characterized by heightened sensitivity to nonthreatening stimuli.

Antipredator responses of wolf spiders (Araneae: Lycosidae) to sensory cues representing an avian predator

Predator detection and subsequent antipredator response behaviours have been documented in many vertebrate and invertebrate animals, although the degree of specificity in predator recognition and response varies. We examined responses of actively courting adult male Schizocosa ocreata (Hentz) wolf spiders to cues indicating the presence of an avian predator, including visual, seismic (substrate vibration) and acoustic (airborne) stimuli. Spiders responded to acoustic (bird call) and seismic (simulated beak tap) stimuli with cessation of courtship and movement, but increased locomotion when presented with a visual stimulus (bird shadow). Spiders responded to experimental playback of avian acoustic stimuli with antipredator behaviour significantly more often and took longer to return to courtship than when exposed to nonthreatening stimuli. Tests of responses on different substrata to isolate sensory modes revealed that spiders perceive airborne sound from bird calls as substratum-conducted vibration. Results indicate that S. ocreata are capable of recognizing sensory cues associated with avian predators and distinguishing them from nonthreatening stimuli, suggesting that bird predation has been a selection factor in shaping behaviour of this wolf spider species.

Detecting the Snake in the Grass

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.

Identification of angry faces in the attentional blink

According to cognitive and neural theories of emotion, attentional processing of innate threat stimuli, such as angry facial expressions, is prioritised over neutral stimuli. To test this hypothesis, the present study used a modified version of the rapid serial visual presentation (RSVP) paradigm to investigate the effect of emotional face stimuli on the attentional blink (AB). The target stimuli were schematic faces which depicted threatening (angry), positive or neutral facial expressions. Results showed that performance accuracy was enhanced (i.e., the AB was reduced) on trials in which the second target was an angry face, rather than a neutral face. Results extend previous research by demonstrating that angry faces reduce the AB, and that this effect is found for schematic facial expressions. These findings further support the proposal that, when there is competition for attentional resources, threat stimuli are given higher priority in processing compared with non-threatening stimuli.

Emotional information processing in repressors: The vigilance–avoidance theory

A vigilance–avoidance theory of the repressive coping style (low trait anxiety and high defensiveness) is presented. The new theory attempts to account for several key findings, including the discrepancy between low self-reported anxiety and high behavioural and physiological indicators of anxiety shown by individuals with a repressive coping style. According to the theory, repressors have an initial rapid vigilant response triggering behavioural and physiological responses and involving attentional and interpretive biases to self-relevant threat stimuli. These biases may be based on negative self-relevant schematic information. This initial vigilant stage is followed by an avoidance stage involving avoidant cognitive biases (attentional, interpretive, and memory) that inhibit the conscious experience of anxiety. Future research should examine systematically the time course of repressors’ reactions to threatening and non-threatening stimuli.

An artificial neural network model of orienting attention toward threatening somatosensory stimuli

An artificial neural network model was designed to test the threat detection hypothesis developed in our experimental studies, where threat detector activity in the somatosensory association areas is monitored by the medial prefrontal cortex, which signals the lateral prefrontal cortex to redirect attention to the threat. As in our experimental studies, simulated threat-evoked activations of all three brain areas were larger when the somatosensory target stimulus was unattended than attended, and the increase in behavioral reaction times when the target stimulus was unattended was smaller for threatening than nonthreatening stimuli. The model also generated a number of novel predictions, for example, the effect of threat on reaction time only occurs when the target stimulus is unattended, and the P3a indexes prefrontal cortex activity involved in redirecting attention toward response processes on that trial and sensory processes on subsequent trials.

Neural Networks of Information Processing in Posttraumatic Stress Disorder: A Functional Magnetic Resonance Imaging Study

Neuroimaging studies report reduced medial prefrontal cortical (particularly anterior cingulate) but enhanced amygdala response to fear signals in posttraumatic Stress Disorder (PTSD). We investigated whether anterior cingulate-amygdala dysregulation in PTSD would generalize to salient, but nonthreat related signals. Individuals with PTSD (n = 14) and age and sex-matched nontraumatized controls (n = 14) completed an auditory oddball paradigm adapted to functional magnetic resonance imaging at a 1.5-T field strength. Controls displayed bilateral activation in ventral anterior cingulate and amygdala networks, and PTSD subjects showed bilateral dorsal anterior cingulate and amygdala activation to targets relative to nontargets. Compared to controls, PTSD subjects showed enhanced responses to targets in the dorsal and rostral anterior cingulate, and left amygdala. Whole-brain analyses confirmed the expected pattern of distributed prefrontal-parietal responses to targets in the oddball task. Greater activity in posterior parietal somatosensory regions was observed in PTSD. Our findings of enhanced anterior cingulate responses in PTSD contrast with reports of reduced activity for threat stimuli, suggesting that the latter may be specific to processing of threat-related content. Activation in rostral and dorsal anterior cingulate, left amygdala and posterior parietal networks in response to salient, nonthreatening stimuli may reflect generalized hypervigilance.

Editorial

Editorial

The sexual inhibition (SIS) and sexual excitation (SES) scales: II. Predicting psychophysiological response patterns

This study evaluated the predictive value of a newly developed measure of the propensity for sexual inhibition and excitation; the Sexual Inhibition & Sexual Excitation Scales (SIS/SES). Sexual, cardiovascular, and startle responses were measured in a group of 40 sexually functional men during the presentation of threatening and nonthreatening erotic films. Two levels of performance demand were created and two films were combined with a distraction task. Participants were assigned to high and low groups for each of the three SIS/SES scales. As predicted, men with high SES scores showed generally higher sexual responses. High and low SIS1 groups did not differ in their responses. Men with high and low SIS2 scores did not differ in their responses to nonthreatening stimuli; however, low SIS2 men showed greater genital response to the threatening stimuli. The findings provide support for the value of the SIS/SES scales in predicting sexual responses.

O modelo da equivalência de estímulos na análise de distúrbios de ansiedade: os efeitos da história experimental e da qualidade de estímulos em sujeitos ansiosos e não-ansiosos

Oito sujeitos, quatro ansiosos e quatro não-ansiosos (escolha livre), poderiam no pré-teste formar relações homogêneas (compostas somente por estímulos ameaçadores ou somente estímulos nãoameaçadores) e relações mistas (compostas por estímulos ameaçadores e por estímulos não-ameaçadores). Para oito outros sujeitos, quatro ansiosos e quatro não-ansiosos (escolha forçada), só era possível formar relações mistas. Após treino de relações mistas, no grupo de escolha livre, os nãoansiosos, formaram tanto relações mistas, quanto homogêneas. Porém, os sujeitos ansiosos, formaram somente relações homogêneas. O desempenho de todos os sujeitos do grupo de escolha forçada não demonstrou preferência em formar qualquer um dos tipos de relações. Esses dados sugerem que a dificuldade dos sujeitos ansiosos em formar relações mistas se deve a uma preexistência de classes ameaçadoras e não-ameaçadoras. Um contexto anterior de escolhas forçadamente mistas interfere no desempenho dos sujeitos ansiosos e não-ansiosos.

Cognitive functioning and anxiety.

Various possible differences in cognitive functioning between those high and low in trait anxiety are considered. Particular emphasis is paid to the hypothesis that individuals high in trait anxiety tend to approach threatening stimuli, whereas those low in trait anxiety tend to avoid such stimuli. The evidence indicates that there are such differences in the processing of threatening stimuli as a function of trait anxiety. However, these differences are found only under certain conditions, for example, when threatening and nonthreatening stimuli are presented concurrently, and when minor rather than major threat is involved.

Repressors' and sensitizers' affective change during free association.

Repressors, sensitizers, and a control group free-associated to threatening and nonthreatening stimuli for time periods ranging from 1 to 40 sec., giving ratings of affective states after each response period. In spite of the fact that sensitizers showed greater “approach” responding, they did not reduce their anxiety levels. The evidence suggests the need to reevaluate the presumed anxiety-reducing function of sensitizing behaviors.

Continuous associative responding to threatening and nonthreatening stimuli by repressors and sensitizers.

Continuous associative responding to threatening and nonthreatening stimuli by repressors and sensitizers.