焦虑对重量感知判断的影响

行动经济理论认为个体对物理环境的感知与其具备的资源有关,而焦虑与资源不足有关。基于此,本研究通过3个实验来探讨3种不同性质的焦虑对重量感知判断的影响。实验1通过身体姿势诱发焦虑,结果发现同放松的身体姿势相比,焦虑的身体姿势能诱发出焦虑且此姿势下个体会认为背包的重量更重。实验2通过具有压力性的外部任务诱发焦虑,结果显示同奇偶判断任务相比,心算任务能诱发出明显的焦虑且此任务下个体将背包的重量判断为更重。实验3探讨特质焦虑的影响,结果发现高特质焦虑个体同低特质焦虑者相比会认为背包的重量更重。本研究表明焦虑会影响个体对物体物理属性的感知。     

Affective state influences perception by affecting decision parameters underlying bias and sensitivity

Studies of the effect of affect on perception often show consistent directional effects of a person's affective state on perception. Unpleasant emotions have been associated with a "locally focused" style of stimulus evaluation, and positive emotions with a "globally focused" style. Typically, however, studies of affect and perception have not been conducted under the conditions of perceptual uncertainty and behavioral risk inherent to perceptual judgments outside the laboratory. We investigated the influence of perceivers' experienced affect (valence and arousal) on the utility of social threat perception by combining signal detection theory and behavioral economics. We compared 3 perceptual decision environments that systematically differed with respect to factors that underlie uncertainty and risk: the base rate of threat, the costs of incorrect identification threat, and the perceptual similarity of threats and nonthreats. We found that no single affective state yielded the best performance on the threat perception task across the 3 environments. Unpleasant valence promoted calibration of response bias to base rate and costs, high arousal promoted calibration of perceptual sensitivity to perceptual similarity, and low arousal was associated with an optimal adjustment of bias to sensitivity. However, the strength of these associations was conditional upon the difficulty of attaining optimal bias and high sensitivity, such that the effect of the perceiver's affective state on perception differed with the cause and/or level of uncertainty and risk.     

Effects of anxiety on the execution of police arrest and self-defense skills

We investigated the effects of anxiety on the execution of police officers' arrest and self-defense skills. Police officers (n=13) performed three tasks in which they kicked, blocked, or restrained an opponent who attacked them with a rubber knife (low anxiety, LA) or a shock knife (high anxiety, HA) in a within-subject design. We analyzed performance (on a 5-point Likert scale), movement times, posture, and movement velocity and acceleration. Results revealed that performance was worse in the HA compared to the LA condition. Furthermore, analysis of full-body movement showed that under increased anxiety, police officers' performance contained characteristics of avoidance behavior, such as faster reactions (to reduce the time being exposed to the threat), leaning further backward (kick), and ducking down (block). In line with recent theoretical developments, it appears that under increased anxiety, police officers were less able to inhibit stimulus-driven processing (fear of getting hit) and enforce goal-directed processing (perform the skill as well as possible) leading to avoidance behavior and a decrease in performance.     

Shoot or don't shoot? Why police officers are more inclined to shoot when they are anxious

We investigated the effect of anxiety on police officers' shooting decisions. Thirty-six police officers participated and executed a low- and high-anxiety video-based test that required them to shoot or not shoot at rapidly appearing suspects that either had a gun and "shot," or had no gun and "surrendered." Anxiety was manipulated by turning on (high anxiety) or turning off (low anxiety) a so-called "shootback canon" that could fire small plastic bullets at the participants. When performing under anxiety, police officers showed a response bias toward shooting, implying that they accidentally shot more often at suspects that surrendered. Furthermore, shot accuracy was lower under anxiety and officers responded faster when suspects had a gun. Finally, because gaze behavior appeared to be unaffected by anxiety, it is concluded that when they were anxious, officers were more inclined to respond on the basis of threat-related inferences and expectations rather than objective, task-relevant visual information.     

Shooting behaviour: How working memory and negative emotionality influence police officer shoot decisions

Previous research on police officer shoot decisions has focussed on the influence of situational factors that lead to the shooting error. Focussing instead on the ‘shooter’, the present study examined whether working memory capacity and threat‐related increases in negative emotionality influenced participant shoot decisions in a simulated shooting task. Following a working memory test, 24 police officers viewed a police‐relevant threatening video while physiological indices of arousal and negative affect were obtained and then completed a computerized shoot‐don't shoot task. Results indicated that lower working memory capacity was associated with a greater likelihood of shooting unarmed targets and a failure to shoot armed targets. Moreover, an interaction effect indicated that these associations were only significant for officers who experienced heightened negative emotionality in response to the video. Results suggest that when negatively aroused via threat, limited working memory capacity increases the risk of shooting error. Copyright © 2009 John Wiley & Sons, Ltd.     

Effects of anxiety on handgun shooting behavior of police officers: a pilot study

Abstract

The current pilot study aimed at providing an initial assessment of how anxiety influences police officers’ shooting behavior. Seven police officers participated and completed an identical shooting exercise under two experimental conditions: low anxiety, against a non-threatening opponent, and high anxiety (HA), against a threatening opponent who occasionally shot back using colored soap cartridges. Measurements included shooting accuracy, movement times, head/body orientation, and blink behavior. Results showed that under HA, shooting accuracy decreased. Underlying this degradation of performance, participants acted faster and made themselves smaller to reduce the chance of being hit. Furthermore, they blinked more often, leading to increases in the amount of time participants had their eyes closed. Findings provide support for attentional control theory, hereby also pointing to possible interventions to improve police officers’ shooting performance under pressure.     

Positive Effects of Imagery on Police Officers' Shooting Performance under Threat

We investigated the effects of imagery on police officers' shooting performance under threat. To this end, 66 officers executed a realistic shooting exercise against an opponent that initially did not shoot back with painful coloured‐soap cartridges (low‐threat condition) followed by a condition in which he did [high‐threat (HT) condition]. In between conditions, participants performed an imagery intervention: one group imagined ‘successful shot execution’ and one imagined ‘successful shot execution under threat, including the accompanying emotions’; a control group received no imagery intervention. Although for the control group shot accuracy was significantly lower in the HT condition than under low‐threat conditions, both imagery groups were able to maintain their shot accuracy in the HT condition, despite increased levels of anxiety. It is concluded that focusing on successful shot execution is pivotal, whereas adding emotional statements does not seem to have an additional positive effect. Copyright © 2013 John Wiley & Sons, Ltd.     

Anxiety and Threat Perception Abnormalities in Normal Children

The current study examined the relationship between childhood anxiety and threat perception abnormalities. Children (N = 105) were exposed to stories reflecting three types of anxiety: social anxiety, separation anxiety, and generalized anxiety. From children's reactions to the stories, a number of threat perception indices were derived. Children's level of anxiety was assessed by means of questionnaires and a structured diagnostic interview. Results indicated that high levels of anxiety, as measured by questionnaires and interview, were accompanied by a high frequency of threat perception, high ratings of threat, a high frequency of threatening interpretations, high levels of negative feelings and cognitions, and an early detection of threat. Furthermore, results seemed to suggest that threat perception abnormalities were mediated by children's general level of anxiety rather than by levels of specific anxiety symptoms.     

On the Role of Vertical Texture Cues in Height Perception

When people judge height from the top looking down they tend to overestimate vertical distance. Initial findings suggest that this perceptual bias may be in part due to the experienced fear of falling. However, previous studies did not control for potentially relevant optical invariants, especially vertical texture gradient cues, that may inform such perceptual judgments. In this study, we examined to what degree texture gradient cues may account for the perceptual bias in height perception. To this end, in 2 different conditions in which vertical texture gradient cues were either present or absent, participants provided distance and size judgments from an elevated position (5.68 m) and from the ground. Results revealed a systematic overestimation of vertical extent and object size when judged from a height. Yet, the absence or presence of texture gradient cues did not differentially influence these judgments. Finally, although fear levels were reported to be larger at the elevated position than on the ground, fear levels did not correlate with the perceptual bias, thereby demanding further research into the mechanisms underlying the perceptual bias in height perception.     

Toward a Comprehensive Understanding of Officers’ Shooting Decisions: No Simple Answers to This Complex Problem

Police officers make life-or-death shooting decisions in complex situations under extreme time pressure. If officers make a mistake, there are dire consequences—they could kill an innocent or be killed themselves. In contrast to prior work's near-exclusive focus on suspect race, the present study examined features of methodology, officers, suspects, and neighborhoods that may affect officers’ shooting decisions. Empirical exploration of officers’ shooting decisions and mistakes is still in its infancy, and given the seriousness and importance of this phenomenon—and the potential for this research to inform policy decisions—additional research is needed.     

Better, Stronger, Faster: Self-Serving Judgment, Affect Regulation, and the Optimal Vigilance Hypothesis

ABSTRACT— Self-serving judgments, in which the self is viewed more favorably than other people, are ubiquitous. Their dynamic variation within individuals may be explained in terms of the regulation of affect. Self-serving judgments produce positive emotions, and threat increases self-serving judgments (a compensatory pattern that restores affect to a set point or baseline). Perceived mutability is a key moderator of these judgments; low mutability (i.e., the circumstance is closed to modification) triggers a cognitive response aimed at affect regulation, whereas high mutability (i.e., the circumstance is open to further modification) activates direct behavioral remediation. Threats often require immediate response, whereas positive events do not. Because of this brief temporal window, an active mechanism is needed to restore negative (but not positive) affective shifts back to a set point. Without this active reset, an earlier threat would make the individual less vigilant toward a new threat. Thus, when people are sad, they aim to return their mood to baseline, often via self-serving judgments. We argue that asymmetric homeostasis enables optimal vigilance, which establishes a coherent theoretical account of the role of self-serving judgments in affect regulation.     

Through the eyes of anxiety: Dissecting threat bias via emotional-binocular rivalry

An extensive body of research has demonstrated that anxious individuals abnormally process threat-related content. Yet, the manner in which clinical anxiety affects the selection of threatening signals and their maintenance within consciousness is yet to be explored. The present study used an emotional binocular rivalry (e-BR) procedure, in which pictures of faces depicting either fearful or neutral expressions competed with pictures of a house for conscious perception. We assumed that first- or cumulative-preferred perception of faces with fearful over neutral expression (i.e., initial or sustained threat bias, respectively) stand for preferential selection or maintenance of fear content in awareness, correspondingly. Unmedicated patients with social anxiety disorder (SAD) and panic disorder (PAD) were compared to healthy controls for threat-related perceptual biases in the e-BR. At first perception of face, both SAD and PAD patients showed a greater initial threat bias than healthy controls. In contrast, at cumulative dwell-time of face, patient groups demonstrated a diminished sustained threat bias relative to healthy controls, yet in a different manner. SAD patients showed a sustained threat bias, though it was smaller than in healthy controls. Furthermore, increased levels of reported anxiety among SAD patients were associated with enhanced sustained perception of neutral faces. PAD patients, on the other hand, showed no sustained threat bias and a diminished cumulative perception of fearful faces with increased levels of anxiety traits. These findings indicate that anxiety disorders commonly involve an initially enhanced selection of threat signals into awareness, followed by disorder-specific manifestation of diminished preferred maintenance of threat in awareness. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

Decision-related action orientation predicts police officers' shooting performance under pressure

Background and Objectives: We aimed to test whether police officers’ trait self-control strength decreases negative effects of high pressure (HP) on state anxiety, shooting behavior, and shooting performance. Design and Methods: Forty-two officers performed a shooting test under both high and low-pressure (LP) conditions. Self-control strength was assessed with the decision-related action orientation (AOD) scale of the Action Control Scale (ACS-90). Effects of AOD on perceived anxiety, heart rate, shooting time, and shot accuracy were estimated and controlled for those of other individual difference measures (i.e. age, police working experience, trait anxiety, and threat-related action orientation). Results: After controlling for baseline values in the LP condition as well as the other individual difference measures, AOD significantly predicted shot accuracy in the HP condition. Conclusions: Results suggest that trait self-control strength in the form of AOD helps officers cope with anxiety and maintain perceptual-motor performance under HP.     

Response inhibition and attentional control in anxiety

Traditionally, anxiety has been associated with a selective attentional bias for threat and a decreased capacity in attentional control. In two different experiments, we investigated whether individuals with different levels of self-reported state anxiety (Experiment 1) and induced anxiety (Experiment 2) had impaired response inhibition processes (attentional control deficit) as characterized by a different response style in the presence of negative stimuli under low and high perceptual load conditions. A go/no-go paradigm with emotional distractors (angry, happy, and neutral faces) was used to provide measures of perceptual sensitivity, inhibition, and response style. Our findings showed that perceptual sensitivity, as assessed by the d' parameter of signal detection theory, was reduced in all participants for angry faces under low perceptual load, where enough perceptual resources were available to be attracted by distractors. Importantly, despite similar perceptual sensitivity, the beta parameter indicated that high state anxiety individuals in both experiments were less flexible at adjusting to task demands in the presence of angry face distractors by adopting a stricter criterion. Implications of findings are discussed within current models of attentional control in anxiety.     

The effects of binocular and motion-generated information on the perception of depth and height

The perception of distance and size in the presence of optical gradient information was investigated under four viewing conditions—binocular view with and without head motion, and monocular view with and without head motion. Subjects (60 adults) matched distance intervals (from 15 to 127 cm) and heights of a target triangle (from 5 to 15 cm) by adjusting the length of a metal tape. Both linear and power functions were fitted to each individual’s distance judgments, and the competing perceptual models were compared. For both models, it was found that binocular information was sufficient to specify relative, but not absolute, distance, that monocular information was sufficient to specify an orderly relation between target distance and judgment but not absolute distance, that average error was less in the binocular conditions, and that perceived distance was not affected in either condition by the addition of head motion. The analysis of size judgments revealed that monocular and binocular judgments did not differ, that matches made with and without head motion did not differ, and that, in all conditions, matches exceeded target heights by an average 30% to 40%. Judged size was also analyzed as a function of target distance. In all conditions but monocular view with head motion, the effect of distance was to increase size judgments. The distance judgments support the hypothesis (Purdy, 1958) that the binocular stimulus carries information that the monocular stimulus does not; they fail to support the hypothesis (Gibson, 1966) that observer motion adds information to the static stimulus. The size judgments support neither hypothesis but suggest an independence of perceived size from perceived distance.     

More than just perception–action recalibration: Walking through a virtual environment causes rescaling of perceived space

Egocentric distances in virtual environments are commonly underperceived by up to 50 % of the intended distance. However, a brief period of interaction in which participants walk through the virtual environment while receiving visual feedback can dramatically improve distance judgments. Two experiments were designed to explore whether the increase in postinteraction distance judgments is due to perception–action recalibration or the rescaling of perceived space. Perception–action recalibration as a result of walking interaction should only affect action-specific distance judgments, whereas rescaling of perceived space should affect all distance judgments based on the rescaled percept. Participants made blind-walking distance judgments and verbal size judgments in response to objects in a virtual environment before and after interacting with the environment through either walking (Experiment 1) or reaching (Experiment 2). Size judgments were used to infer perceived distance under the assumption of size–distance invariance, and these served as an implicit measure of perceived distance. Preinteraction walking and size-based distance judgments indicated an underperception of egocentric distance, whereas postinteraction walking and size-based distance judgments both increased as a result of the walking interaction, indicating that walking through the virtual environment with continuous visual feedback caused rescaling of the perceived space. However, interaction with the virtual environment through reaching had no effect on either type of distance judgment, indicating that physical translation through the virtual environment may be necessary for a rescaling of perceived space. Furthermore, the size-based distance and walking distance judgments were highly correlated, even across changes in perceived distance, providing support for the size–distance invariance hypothesis.     

Emotional deceit: False words versus false action

What speaks louder, false words or false action? Raters assessed the anxiety level of 10 actors portraying their actual anxiety level and simulated displays of high anxiety. Raters were required to base judgments on either video cues alone or audio cues alone. Findings indicate that false words speak louder than false action, with audio-based judgments generating greater judgmental error in both straight and dissembled anxiety conditions. Although raters expressed equal confidence in judgments based on either verbal or nonverbal cues, results indicated that verbal cues played a larger role in emotional deceit. Differences between real and simulated anxiety cues were delineated, suggesting ways of detecting emotional deception. Results were discussed in light of current thought regarding channel contribution in deception.     

The police officer's terrorist dilemma: trust resilience following fatal errors

Suicide attacks have raised the stakes for officers deciding whether or not to shoot a suspect (‘Police Officer's Terrorist Dilemma’). Despite high‐profile errors we know little about how trust in the police is affected by their response to the terrorist threat. Building on a conceptualisation of lay observers as intuitive signal detection theorists, a general population sample (N = 1153) were presented with scenarios manipulated in terms of suspect status (Armed/Unarmed), officer decision (Shoot/Not Shoot) and outcome severity (e.g. suspect armed with Bomb/Knife; police shoot suspect/suspect plus child bystander). Supporting predictions, people showed higher trust in officers who made correct decisions, reflecting good discrimination ability and who decided to shoot, reflecting an ‘appropriate’ response bias given the relative costs and benefits. This latter effect was moderated by (a) outcome severity, suggesting it did not simply reflect a preference for a particular type of action, and (b) preferences for a tough stance towards terrorism indexed by Right‐Wing Authoritarianism (RWA). Despite loss of civilian life, failure to prevent minor terror attacks resulted in no loss of trust amongst people low in RWA, whereas among people high in RWA trust was positive when police erroneously shot an unarmed suspect. Relations to alternative definitions of trust and procedural justice research are discussed. Copyright © 2007 John Wiley & Sons, Ltd.     

The Effects of Suspect Race and Situation Hazard on Police Officer Shooting Behavior

Shooting incidents involving patrol officers are examined for the effect of suspect race and degree of hazard in the number of shots fired and hits made on suspects. Additional tests examine frequencies of shooting incidents among Blacks and Whites with respect to city population and various measures of police-citizen contact. Finally, fatalities are examined with respect to involvement in shooting and arrest rates. The results suggest an effect for degree of hazard; however, there was no evidence to suggest police bias against Blacks.