Is it dangerous? The role of an emotional visual search strategy and threat-relevant training in the detection of guns and knives

Counter-terrorism strategies rely on the assumption that it is possible to increase threat detection by providing explicit verbal instructions to orient people's attention to dangerous objects and hostile behaviours in their environment. Nevertheless, whether verbal cues can be used to enhance threat detection performance under laboratory conditions is currently unclear. In Experiment 1, student participants were required to detect a picture of a dangerous or neutral object embedded within a visual search display on the basis of an emotional strategy ‘is it dangerous?’ or a semantic strategy ‘is it an object?’. The results showed a threat superiority effect that was enhanced by the emotional visual search strategy. In Experiment 2, whilst trainee police officers displayed a greater threat superiority effect than student controls, both groups benefitted from performing the task under the emotional than semantic visual search strategy. Manipulating situational threat levels (high vs. low) in the experimental instructions had no effect on visual search performance. The current findings provide new support for the language-as-context hypothesis. They are also consistent with a dual-processing account of threat detection involving a verbally mediated route in working memory and the deployment of a visual template developed as a function of training.     

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.     

Visual search for emotional faces in children

The ability to rapidly detect facial expressions of anger and threat over other salient expressions has adaptive value across the lifespan. Although studies have demonstrated this threat superiority effect in adults, surprisingly little research has examined the development of this process over the childhood period. In this study, we examined the efficiency of children's facial processing in visual search tasks. In Experiment 1, children (N=49) aged 8 to 11 years were faster and more accurate in detecting angry target faces embedded in neutral backgrounds than vice versa, and they were slower in detecting the absence of a discrepant face among angry than among neutral faces. This search pattern was unaffected by an increase in matrix size. Faster detection of angry than neutral deviants may reflect that angry faces stand out more among neutral faces than vice versa, or that detection of neutral faces is slowed by the presence of surrounding angry distracters. When keeping the background constant in Experiment 2, children (N=35) aged 8 to 11 years were faster and more accurate in detecting angry than sad or happy target faces among neutral background faces. Moreover, children with higher levels of anxiety were quicker to find both angry and sad faces whereas low anxious children showed an advantage for angry faces only. Results suggest a threat superiority effect in processing facial expressions in young children as in adults and that increased sensitivity for negative faces may be characteristic of children with anxiety problems.     

Aging and visual search: automatic and controlled attentional bias to threat faces

Using a visual search paradigm, we investigated how age affected attentional bias to emotional facial expressions. In Experiments 1 and 2, participants searched for a discrepant facial expression in a matrix of otherwise homogeneous faces. Both younger and older adults showed a more effective search when the discrepant face was angry rather than happy or neutral. However, when the angry faces served as non-target distractors, younger adults' search was less effective than happy or neutral distractor conditions. In contrast, older adults showed a more efficient search with angry distractors than happy or neutral distractors, indicating that older adults were better able to inhibit angry facial expressions. In Experiment 3, we found that even a top-down search goal could not override the angry face superiority effect in guiding attention. In addition, RT distribution analyses supported that both younger and older adults performed the top-down angry face search qualitatively differently from the top-down happy face search. The current research indicates that threat face processing involves automatic attentional shift and a controlled attentional process. The current results suggest that age only influenced the controlled attentional process.     

A threat-detection advantage in those with autism spectrum disorders

Identifying threatening expressions is a significant social perceptual skill. Individuals with autism spectrum disorders (ASD) are impaired in social interaction, show deficits in face and emotion processing, show amygdala abnormalities and display a disadvantage in the perception of social threat. According to the anger superiority hypothesis, angry faces capture attention faster than happy faces in individuals with a history of typical development [Hansen, C. H., & Hansen, R. D. (1988). Finding the face in the crowd: An anger superiority effect. Journal of Personality and Social Psychology, 54(6), 917–924]. We tested threat detection abilities in ASD using a facial visual search paradigm. Participants were asked to detect an angry or happy face image in an array of distracter faces. A threat-detection advantage was apparent in both groups: participants showed faster and more accurate detection of threatening over friendly faces. Participants with ASD showed similar reaction time, but decreased overall accuracy compared to controls. This provides evidence for less robust, but intact or learned implicit processing of basic emotions in ASD.     

Conserved evolutionary history for quick detection of threatening faces

Humans quickly recognize threats such as snakes and threatening faces, suggesting that human ancestors evolved specialized visual systems to detect biologically relevant threat stimuli. Although non-human primates also detect snakes quickly, it is unclear whether primates share the efficient visual systems to process the threatening faces of their conspecifics. Primates may not necessarily process conspecific threats by facial expressions, because threats from conspecifics in natural situations are often accompanied by other cues such as threatening actions (or attacks) and vocal calls. Here, we show a similar threat superiority effect in both humans and macaque Japanese monkeys. In visual search tasks, monkeys and humans both responded to pictures of a threatening face of an unfamiliar adult male monkey among neutral faces faster than to pictures of a neutral face among threatening faces. However, the monkeys’ response times to detect deviant pictures of a non-face stimulus were not slower when it was shown among threat faces than when it was shown among neutral faces. These results provide the first evidence that monkeys have an attentional bias toward the threatening faces of conspecifics and suggest that threatening faces are evolutionarily relevant fear stimuli. The subcortical visual systems in primates likely process not only snakes, but also more general biological threat-relevant stimuli, including threatening conspecific faces.     

Visual search for emotional expressions: Effect of stimulus set on anger and happiness superiority

Prior reports of preferential detection of emotional expressions in visual search have yielded inconsistent results, even for face stimuli that avoid obvious expression-related perceptual confounds. The current study investigated inconsistent reports of anger and happiness superiority effects using face stimuli drawn from the same database. Experiment 1 excluded procedural differences as a potential factor, replicating a happiness superiority effect in a procedure that previously yielded an anger superiority effect. Experiments 2a and 2b confirmed that image colour or poser gender did not account for prior inconsistent findings. Experiments 3a and 3b identified stimulus set as the critical variable, revealing happiness or anger superiority effects for two partially overlapping sets of face stimuli. The current results highlight the critical role of stimulus selection for the observation of happiness or anger superiority effects in visual search even for face stimuli that avoid obvious expression related perceptual confounds and are drawn from a single database.     

Threat and selective exposure: the moderating role of threat and decision context on confirmatory information search after decisions

Previous studies on the impact of perceived threat on confirmatory information search (selective exposure) in the context of decision making have yielded mixed results. Some studies have suggested that confirmatory information search is reduced, yet others have found contradictory effects. The present series of 5 studies consistently found that the crucial moderator for these inconsistent findings was whether the induced threat was contextually related to the subsequent decision and information search tasks. Contextual incongruence (e.g., an induction of terrorist threat followed by an economic decision case) results in reduced levels of confirmatory information search, whereas a congruent threat (e.g., an induction of terrorist threat followed by a decision case on terrorism) results in increased levels of confirmatory information search. Analyses of the underlying psychological processes revealed that decision-unrelated threat inductions increase decision makers' experienced decision uncertainty, thus reducing confirmatory information search.     

时间任务需求对无关情绪面孔注意捕获的影响

注意捕获是指与任务无关的刺激能够不自觉地吸引注意的现象。实验一采用视觉搜索任务,考察与主任务无关的情绪面孔的注意捕获水平及其机制,实验二进一步探究时间任务需求对无关情绪面孔注意捕获的影响。结果发现:与其他情绪面孔相比,愤怒的情绪面孔捕获了更多的注意,且受到整体情绪加工的影响;时间任务需求影响了目标刺激的注意选择,但愤怒优势效应不受到时间任务需求的影响,因此可能是一种较为自动化的加工过程。     

Affective significance enhances covert attention: Roles of anxiety and word familiarity

To investigate the processing of emotional words by covert attention, threat-related, positive, and neutral word primes were presented parafoveally (2.2° away from fixation) for 150 ms, under gaze-contingent foveal masking, to prevent eye fixations. The primes were followed by a probe word in a lexical-decision task. In Experiment 1, results showed a parafoveal threat–anxiety superiority: Parafoveal prime threat words facilitated responses to probe threat words for high-anxiety individuals, in comparison with neutral and positive words, and relative to low-anxiety individuals. This reveals an advantage in threat processing by covert attention, without differences in overt attention. However, anxiety was also associated with greater familiarity with threat words, and the parafoveal priming effects were significantly reduced when familiarity was covaried out. To further examine the role of word knowledge, in Experiment 2, vocabulary and word familiarity were equated for low- and high-anxiety groups. In these conditions, the parafoveal threat–anxiety advantage disappeared. This suggests that the enhanced covert-attention effect depends on familiarity with words.     

Finding a face in the crowd: testing the anger superiority effect in Asperger Syndrome

Social threat captures attention and is processed rapidly and efficiently, with many lines of research showing involvement of the amygdala. Visual search paradigms looking at social threat have shown angry faces 'pop-out' in a crowd, compared to happy faces. Autism and Asperger Syndrome (AS) are neurodevelopmental conditions characterised by social deficits, abnormal face processing, and amygdala dysfunction. We tested adults with high-functioning autism (HFA) and AS using a facial visual search paradigm with schematic neutral and emotional faces. We found, contrary to predictions, that people with HFA/AS performed similarly to controls in many conditions. However, the effect was reduced in the HFA/AS group when using widely varying crowd sizes and when faces were inverted, suggesting a difference in face-processing style may be evident even with simple schematic faces. We conclude there are intact threat detection mechanisms in AS, under simple and predictable conditions, but that like other face-perception tasks, the visual search of threat faces task reveals atypical face-processing in HFA/AS.     

The face in the crowd revisited: a threat advantage with schematic stimuli

Schematic threatening, friendly, and neutral faces were used to test the hypothesis that humans preferentially orient their attention toward threat. Using a visual search paradigm, participants searched for discrepant faces in matrices of otherwise identical faces. Across 5 experiments, results consistently showed faster and more accurate detection of threatening than friendly targets. The threat advantage was obvious regardless of whether the conditions favored parallel or serial search (i.e., involved neutral or emotional distractors), and it was valid for inverted faces. Threatening angry faces were more quickly and accurately detected than were other negative faces (sad or "scheming"), which suggests that the threat advantage can be attributed to threat rather than to the negative valence or the uniqueness of the target display.     

Speeded detection and increased distraction in fear of spiders: evidence from eye movements

Anxiety patients exhibit attentional biases toward threat, which have often been demonstrated as increased distractibility by threatening stimuli. In contrast, speeded detection of threat has rarely been shown. Therefore, the authors studied both phenomena in 3 versions of a visual search task while eye movements were recorded continuously. Spider-fearful individuals and nonanxious control participants participated in a target search task, an odd-one-out search task, and a category search task. Evidence for disorder-specific increased distraction by threat was found in all tasks, whereas speeded threat detection did not occur in the target search task. The implications of these findings for cognitive theories of anxiety are discussed, particularly in relation to the concept of disengagement from threat.     

Affective significance enhances covert attention: roles of anxiety and word familiarity

To investigate the processing of emotional words by covert attention, threat-related, positive, and neutral word primes were presented parafoveally (2.2 degrees away from fixation) for 150 ms, under gaze-contingent foveal masking, to prevent eye fixations. The primes were followed by a probe word in a lexical-decision task. In Experiment 1, results showed a parafoveal threat-anxiety superiority: Parafoveal prime threat words facilitated responses to probe threat words for high-anxiety individuals, in comparison with neutral and positive words, and relative to low-anxiety individuals. This reveals an advantage in threat processing by covert attention, without differences in overt attention. However, anxiety was also associated with greater familiarity with threat words, and the parafoveal priming effects were significantly reduced when familiarity was covaried out. To further examine the role of word knowledge, in Experiment 2, vocabulary and word familiarity were equated for low- and high-anxiety groups. In these conditions, the parafoveal threat-anxiety advantage disappeared. This suggests that the enhanced covert-attention effect depends on familiarity with words.     

情绪面孔搜索不对称性：情绪观与知觉观的争议

情绪面孔搜索不对称性是指当负性情绪面孔作为目标, 正性情绪面孔作为分心物时, 其搜索速度比正性情绪面孔作为目标时(负性情绪面孔作为分心物)更快。对于这一现象的解释存在争议, 研究者主要从不同情绪面孔在情绪因素和知觉因素两个方面的差异进行解释。来自行为研究和认知神经科学的证据对情绪面孔搜索不对称性效应的解释主要有威胁性刺激捕获假设和情绪摆脱假设的情绪观, 以及嘴部差异说、闭合结构说、知觉组群说以及其他面部特征假设的知觉观。经过对比评价两类观点的理论异同和实验证据认为未来的研究可以整合情绪因素和知觉因素来解释该效应。     

Size of defeat and liking for superior and similar ability competitors

Data are reported supporting the view that a competitor's pronounced superiority in ability can serve the positive function of reducing threat to self-esteem stemming from severe negative comparisons by rendering these comparisons irrelevant. Females of apparently comparable ability, compared their performances on a test said to measure cognitive fluency. A competitor's promotion to a higher level of ability (i.e., being designated as incomparably superior by an outside agent) caused an initially comparable competitor who decisively defeated the subject to be eliminated as a relevant comparison threat and to be liked more than a nonpromoted competitor who only marginally defeated the subject and hence remained comparable. A promoted competitor who marginally defeated the subject and a nonpromoted competitor who decisively defeated the subject were relatively disliked. Perceived ability and threat data together with observer control group findings indicated that this liking pattern was a function of differential comparison threat and not of the competitors' objective stimulus characteristics.     

Disentangling the facilitating and hindering effects of threat-related stimuli – A visual search study

Although large body of research has demonstrated the attention-grabbing nature of threat-related stimuli, threat could also facilitate attentional processes. Previous studies suggest a linear relationship between the facilitating effect of the arousal level conveyed by threat and performance on visual search tasks. Due to the temporal competition bias favouring stimuli with higher arousal level, this could be more pronounced for shorter onset times. Here, through two experiments we aimed to disentangle the two effects by using a visual search paradigm that allowed us to separate the emotional stimuli and the cognitive task. We manipulated stimulus onset time and threat intensity. Participants saw neutral and threatening pictures as priming stimuli, and then, they had to find numbers in ascending order in a matrix array. We measured the reaction time for finding the first number, and search time for finding all the numbers. Our results showed that when the priming stimulus is presented, longer threatening pictures produced longer reaction times compared to neutral ones, which was reversed with increase in arousal. We did not find any significant effects for the shorter onset time. Further theoretical and methodological implications are discussed.     

Processing efficiency in anxiety: Evidence from eye-movements during visual search

It is generally held that anxiety is characterized by an attentional bias for threatening information. In recent years there has been an important debate whether these biases reside at the level of attentional selection (threat detection) or attentional processing after threat detection (attentional disengagement). In a visual search task containing emotional facial expressions, eye-movements were examined before and after threat detection in high and low trait anxious individuals to further elucidate the temporal unfolding of attentional bias. Results indicated that high-anxious individuals neither showed facilitated orienting to threat nor impaired disengagement of visual attention from threat. Interestingly, the presence of threat in the visual search display was associated with increased decision times in high-anxious individuals. These results challenge some of the current views on attentional bias to threat but indicate that emotional information reduces processing efficiency in anxiety.     

The effect of face inversion on the detection of emotional faces in visual search

Past literature has indicated that face inversion either attenuates emotion detection advantages in visual search, implying that detection of emotional expressions requires holistic face processing, or has no effect, implying that expression detection is feature based. Across six experiments that utilised different task designs, ranging from simple (single poser, single set size) to complex (multiple posers, multiple set sizes), and stimuli drawn from different databases, significant emotion detection advantages were found for both upright and inverted faces. Consistent with past research, the nature of the expression detection advantage, anger superiority (Experiments 1, 2 and 6) or happiness superiority (Experiments 3, 4 and 5), differed across stimulus sets. However both patterns were evident for upright and inverted faces. These results indicate that face inversion does not interfere with visual search for emotional expressions, and suggest that expression detection in visual search may rely on feature-based mechanisms.     

Anxiety and attention to threatening pictures

Previous research using attentional search tasks has revealed an anxiety-related bias favouring attention to threatening words when they are presented simultaneously with emotionally neutral words. In Experiment 1, using a similar task, a related effect was found here with emotionally threatening pictures. When pictures were used as location cues in a second experiment, high-trait anxious individuals were slower than less anxious controls when responding to targets requiring attentional disengagement from threat, and they were slower in general with pictures judged to be highly threatening. In a third experiment using the same task but with a longer cue exposure, a related disengagement difficulty occurred across both groups, although the more general slowing with severe threat was again confined to the anxious group. We conclude that attentional bias involves both a specific difficulty in disengaging attention from the location of any threat and a more general interference effect that is related to threat level.