Effects of stress and anxiety on the processing of threat stimuli

Two experiments extended the work of MacLeod and Mathews (1988) and examined whether a cognitive bias for threat information is a function of state or trait anxiety. Color-naming and attention deployment tasks were used to assess the effects of a stress manipulation procedure on attentional responses in high and low trait anxious subjects. Subjects under high stress selectively allocated processing resources toward threat stimuli, irrespective of their trait anxiety level. There was no consistent evidence of a cognitive bias associated with trait anxiety, and the effect of the stress manipulation did not appear to be mediated by state anxiety. It was suggested that trait factors do not modify attentional biases associated with acute stress, but may influence such biases when stress is prolonged.     

Attentional bias in high- and low-anxious individuals: evidence for threat-induced effects on engagement and disengagement

Attentional bias to threatening visual stimuli (words or pictures) is commonly present in anxious individuals, but not in non-anxious people. There is evidence to show that attentional bias to threat can be induced in all individuals when threat is imposed by threat not of symbolic nature, but by cues that predict aversive stimulation (loud noise or electric shock). However, it is not known whether attentional bias in such situations is still influenced by individual differences in anxiety. This question was addressed in two experiments using a spatial cuing task in which visual cues predicted the occurrence of an aversive event consisting of a loud human scream. Speeded attentional engagement to threat cues was positively correlated with trait anxiety in Experiment 1. Experiment 2 showed that speeded attentional engagement was present only in participants selected for high anxiety but not in low-anxious participants. In both experiments, slower disengagement from threat cues was found in all participants, irrespective of their trait anxiety levels.     

Attentional bias in high- and low-anxious individuals: Evidence for threat-induced effects on engagement and disengagement

Attentional bias to threatening visual stimuli (words or pictures) is commonly present in anxious individuals, but not in non-anxious people. There is evidence to show that attentional bias to threat can be induced in all individuals when threat is imposed by threat not of symbolic nature, but by cues that predict aversive stimulation (loud noise or electric shock). However, it is not known whether attentional bias in such situations is still influenced by individual differences in anxiety. This question was addressed in two experiments using a spatial cuing task in which visual cues predicted the occurrence of an aversive event consisting of a loud human scream. Speeded attentional engagement to threat cues was positively correlated with trait anxiety in Experiment 1. Experiment 2 showed that speeded attentional engagement was present only in participants selected for high anxiety but not in low-anxious participants. In both experiments, slower disengagement from threat cues was found in all participants, irrespective of their trait anxiety levels.     

Attentional bias to threat: Roles of trait anxiety, stressful events, and awareness

Attentional biases for threat stimuli were assessed in high and low trait anxious subjects (n = 66) using a probe detection task. To examine the effects of trait anxiety and situational stressors, each subject was tested three times: Under no stress, laboratory-induced stress, and examination-induced stress. To evaluate the role of awareness, half the word stimuli were presented very briefly (14 msec) and masked, and the other half were presented for 500 msec without a mask. Results showed that high trait anxious subjects under exam stress showed an attentional bias towards unmasked threat stimuli compared with low trait subjects. This effect was not found under lab-induced stress, suggesting that the attentional bias for unmasked threat in high trait subjects may be a function of a prolonged stressor, rather than a transient increase in state anxiety. The results from the masked exposure condition were not predicted; high trait anxious subjects shifted attention towards the spatial location of threat words despite lack of awareness of their lexical content, but this bias was only apparent in the no-stress condition. The results are discussed in relation to recent cognitive theories of anxiety.     

Eye movements reveal mechanisms underlying attentional biases towards threat

Mechanisms underlying attentional biases towards threat (ABTs), such as attentional avoidance and difficulty of disengagement, are still unclear. To address this issue, we recorded participants' eye movements during a dot detection task in which threatening or neutral stimuli served as peripheral cues. We evaluated response times (RTs) in trials where participants looked at the central fixation cross (not at the cues), as they were required, and number and duration of (unwanted) fixations towards threatening or neutral cues; in all analyses trait anxiety was treated as a covariate. Difficulty in attentional disengagement (longer RTs) was found when peripheral threatening stimuli were presented for 100?ms. Moreover, we observed significantly shorter (unwanted) fixations on threatening than on neutral peripheral stimuli, compatible with an avoidance bias, for longer presentation times. These findings demonstrate that, independent of trait anxiety levels, disengagement bias occurs without eye movements, whereas eye movements are implied in threat avoidance.     

Gender differences in salivary alpha-amylase and attentional bias towards negative facial expressions following acute stress induction

This study investigated gender differences in two key processes involved in anxiety, arousal and attentional bias towards threat. Arousal was assessed using salivary alpha-amylase (sAA), a biomarker of noradrenergic arousal and attention bias using a dot-probe task. Twenty-nine women and 27 men completed the dot-probe task and provided saliva samples before and after a stress induction [cold pressor stress (CPS) test]. Women displayed a significant increase in arousal (sAA) following the stressor compared to men, who displayed a significant reduction in arousal. Reaction time data revealed a significant avoidance of threat in women at baseline, but a significant change to an attention bias towards threat following the stressor. Men did not significantly respond to the stressor in terms of attentional bias. These findings suggest that women are more reactive to a stressor than men, and display an initial avoidance response to threat, but an attentional bias towards threat following stress.     

Selective attention to threat: A test of two cognitive models of anxiety

Two experiments evaluated differential predictions from two cognitive formulations of anxiety. According to one view, attentional biases for threat reflect vulnerability to anxiety; and as threat inputs increase, high trait anxious individuals should become more vigilant, and low trait individuals more avoidant, of threat (Williams, Watts, MacLeod, & Mathews, 1988, 1997). However, according to a “cognitive-motivational” view, trait anxiety influences the appraisal of stimulus threat value, rather than the direction of attentional bias, and both high and low trait anxious individuals should exhibit greater vigilance for high rather than mild threat stimuli (Mogg & Bradley, 1998). To test these predictions, two experiments examined the effect of manipulating stimulus threat value on the direction of attentional bias. The stimuli included high threat and mild threat pictorial scenes presented in a probe detection task. Results from both studies indicated a significant main effect of stimulus threat value on attentional bias, as there was increased vigilance or reduced avoidance of threat, as threat value increased. This effect was found even within low trait anxious individuals, consistent with the “cognitive-motivational” view. Theoretical and clinical implications are discussed.     

Attentive processing of threat and adult attachment: a dot-probe study

We examined selective attention to threat stimuli as a function of individual differences in adult attachment. Participants completed a dot-probe task in which a general threat word, attachment-related threat word, general positive or attachment-related positive word was presented together with a neutral word. Results showed that attachment anxiety and avoidance were associated with an attentional bias away from attachment threat words. This attentional avoidance effect was best predicted by the interaction between attachment anxiety and avoidance and not by their unique main effects. The findings are discussed in terms of attachment theory and its relation to attentional biases observed in psychopathology.     

The interaction effect of attentional bias and attentional control on dispositional anxiety among adolescents

Research has shown that children and adolescents with attentional control deficits tend to have high anxiety and exhibit threat‐related selective attentional bias. This study aimed to investigate how positive and negative attentional biases would interact with attentional control on dispositional anxiety. One hundred and twenty participants aged 18 years of age or younger participated in a visual dot‐probe task to measure their attentional bias and completed psychological questionnaires to measure their trait anxiety, and attentional control. Mean reaction times to the probe in milliseconds were used to measure attentional bias. Overall, our participants showed a bigger tendency towards attending to positive emotional stimuli than to negative emotional stimuli. Adolescents with high dispositional anxiety showed poorer attentional control. Regression analyses showed that attentional control interact with negative attentional bias to affect anxiety. For participants with high attentional control, higher negative attentional bias was associated with lower trait anxiety. Trait anxiety was not related to negative attentional bias for participants with low attentional control. Positive attentional bias showed no significant relationship with dispositional anxiety, either alone or in interaction with attentional control. Theoretical and clinical implications of the findings are also discussed.     

Anxiety and the allocation of attention to threat

Using a probe detection technique we have recently demonstrated that anxious subjects consistently deploy attention towards threat-related stimuli, whereas non-anxious controls tend to move attention away from such material (MacLeod, Mathews, & Tata, 1986).

The current study employed the same paradigm but attempted to distinguish the role of trait and state anxiety by testing high- and low-trait students when state anxiety was relatively low (12 weeks before a major examination) and again when it was relatively high (one week before this examination). High-trait subjects alone tended to shift attention towards generally threatening material on both test occasions. Results for examination-related stimuli were more complex. Increased proximity to the examination was associated with an increase in attentional bias towards such threat stimuli in high-trait subjects, but with increased attentional avoidance of such stimuli in low-trait subjects. It is suggested that the attentional response to currently relevant stress-related stimuli may be associated with neither trait nor state anxiety alone, but with an interactive function involving both these variables. These results are discussed in relation to existing models of emotion and cognition, and alternative interpretations of the findings are considered.     

Prepared for the best: readiness to modify attentional processing and reduction in anxiety vulnerability in response to therapy

Individuals differ in the extent to which their vulnerability to anxiety is reduced by psychological therapy. However, the cognitive basis for such individual differences is still poorly understood. To test a cognitive account of differences in anxiety reduction in response to treatment, the present study examined individuals undergoing group therapy for social anxiety disorder. We assessed whether differences in their readiness to adopt selective attentional processing in response to an experimental contingency predicted positive changes in a range of anxiety measures in response to treatment. Findings were consistent with the position that readiness to alter attentional processing bias may underpin individual differences in the tendency to respond to positive experiential conditions, such as group therapy, by reducing anxiety vulnerability.     

Attention to Positive and Negative Social-Evaluative Words: Investigating the Effects of Social Anxiety,Trait Anxiety and Social Threat

The study investigated how attention to negative (threatening) and positive social-evaluative words is affected by social anxiety, trait anxiety and the expectation of social threat. High and low socially anxious individuals carried out a modified dot-probe task either while expecting to give a speech or under non-threatening conditions. High socially anxious individuals showed no significant attentional bias towards or away from social-evaluative words. This result significantly contrasted with an identical design that showed avoidance of emotional faces in high socially anxious participants drawn from the same population (Mansell et al ., 1999). Participants who expected to give a speech showed less attentional avoidance of negative and positive social-evaluative words. High trait anxiety was associated with selective attention to negative relative to positive social-evaluative words, consistent with earlier findings of attention to threat cues in high trait-anxious individuals. Implications for designing attention tasks and attentional bias across different dimensions of anxiety are discussed.     

Contrasting two accounts of anxiety-linked attentional bias: selective attention to varying levels of stimulus threat intensity

Previous research has established that clinical anxiety patients and nonclinical populations with high levels of anxiety vulnerability characteristically orient attention toward moderately threatening stimuli. In contrast, populations with low levels of anxiety vulnerability typically orient attention away from such stimuli. The differing experimental predictions generated by 2 classes of hypothetical explanation for this anxiety-linked attentional discrepancy were tested, using attentional probe methodology to compare the attentional responses of high and low trait anxious individuals to facial stimuli of differing threat intensities. The results support the view that all individuals orient attention away from mildly threatening stimuli and toward strongly threatening stimuli, with differences in anxiety vulnerability reflecting the intensity of stimulus threat required to elicit the attentional vigilance response.     

Malleability of attentional bias for positive emotional information and anxiety vulnerability

Recent research supports a causal link between attentional bias for negative emotional information and anxiety vulnerability. However, little is known about the role of positive emotional processing in modulating anxiety reactivity to stress. In the current study, we used an attentional training paradigm designed to experimentally manipulate the processing of positive emotional cues. Participants were randomly assigned to complete a computerized probe detection task designed to induce selective processing of positive stimuli or to a sham condition. Following training, participants were exposed to a laboratory stressor (i.e., videotaped speech), and state anxiety and positive affect in response to the stressor were assessed. Results revealed that individual variability in the capacity to develop an attentional bias for positive information following training predicted subsequent emotional responses to the stressor. Moreover, individual differences in social anxiety, but not depression, moderated the effects of the attentional manipulation, such that, higher levels of social anxiety were associated with diminished attentional allocation toward positive cues. The current findings point to the potential value of considering the role of positive emotional processing in anxiety vulnerability.     

Attentional control moderates fearful responding to a 35% CO(2) challenge

Attentional control (AC) is an individual difference variable indexing the ability to voluntarily focus attention and shift attention when desired. AC is thought to impact the experience of fear by facilitating the disengagement of attention from threat and promoting the deployment of attentional resources toward regulatory or coping strategies. Whereas previous research has focused on visual threat cues, in the current study we examined whether this model also applies to interoceptive threat by evaluating the extent to which individual differences in AC moderated the relationship between trait anxiety and self-reported fear in response to a single vital capacity inhalation of a 35% CO(2), 65% balanced O(2) gas mixture. The sample comprised a large nonclinical group of young adults (N=128). Results indicated that AC moderated the relationship between trait anxiety and fearful responding to the challenge. Findings suggest that AC plays a significant and clinically important role in modulating self-reported fear.     

急性应激对威胁刺激注意定向和注意解除的影响:认知神经机制研究

急性应激和注意偏向是焦虑障碍和创伤后应激障碍发生和症状保持的两个重要因素。急性应激导致交感神经系统激活以及儿茶酚胺和糖皮质激素分泌增加,因而影响对威胁刺激的注意偏向。但是急性应激如何影响注意偏向中的注意定向和注意解除尚不清楚。本项目采用点探测任务、威胁线索空间提示任务,结合恐惧条件反射、眼动和事件相关电位技术,研究急性应激对注意定向和注意解除影响的认知神经机制。研究结果可为治疗焦虑和创伤后应激障碍提供支持,为公共卫生管理政策的制定提供建议。     

Plasticity in attention: implications for stress response in children

Attention bias has been suggested as an etiological and maintaining factor in anxiety. However, empirical evidence establishing this causal association is scarce and has been provided only in adults. In this preliminary study, we tested whether an induction of attentional bias can cause changes in vulnerability to stress in children reporting normal anxiety levels. Twenty-six 7-12 year-old children were randomly assigned to two groups. One group was exposed to a training condition designed to induce an attentional bias away from threat. The other group was exposed to a training condition designed to induce an attentional bias toward threat. Children who were trained to attend to threat developed attentional vigilance to threat-related information. The training procedure was ineffective with children who were trained to avoid threat, and their attention remained unbiased. Children from both training groups reported elevated depression scores following stress-induction. However, only the children who were trained to attend to threat subsequently reported elevations in anxiety. The findings suggest that biased attentional responses to threat, among children, can exert a specific influence on the tendency to experience anxiety in the face of stress.     

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.     

Individual differences in the impact of attentional bias training on cardiovascular responses to stress in women

Experimental studies show that training people to attend to negative stimuli makes them more likely to respond with greater anxiety to stress. The present study investigated this effect in students using measures of cardiovascular responses to stress and examined whether individual differences influence the impact of attention training on stress responses. Using a standard dot probe task, 30 participants underwent negative attentional bias training and 34 participants underwent anti-negative training before completing a stressful speech task. Results indicated that, overall, participants exhibited acclimatization to the procedures (indicated by a dip in blood pressure post-training) and normal stress responding (indicated by elevated blood pressure in response to stress; p<.001). However, consideration of participants' scores for neuroticism/emotional-stability revealed important differences in how the intervention impacted on cardiovascular profiles (p=.008). For participants with high neuroticism scores, the negative attentional bias intervention elicited more exaggerated stress responding than the anti-negative intervention. For those with low neuroticism scores (i.e., emotionally stable participants), the anti-negative intervention was associated with elevated post-intervention blood pressure and higher blood pressure reactivity to stress. These findings provide evidence of the impact of attentional bias manipulation on physiological stress reactivity and suggest the effect is highly contingent on individual temperaments.     

Effects of threat cues on attentional shifting, disengagement and response slowing in anxious individuals

According to cognitive models of anxiety, attentional biases for threat may cause or maintain anxiety states. Previous research using spatial cueing tasks has been interpreted in terms of difficulty in disengaging attention from threat in anxious individuals, as indicated by contrasts of response times (RTs) from threat cue versus neutral cue trials. However, on spatial cueing tasks, differences in RT between threat cue and neutral cue trials may stem from a slowing effect of threat on RT, as well as effects on allocation of visuospatial attention. The present study examined the effects of threat cues on both attentional cueing and response slowing. High and low anxious individuals completed a central cue task, which assessed threat-related response slowing, and a spatial cueing task, which assessed attentional biases for angry, happy and neutral faces. Results indicated that interpretation of the anxiety-related bias for threat depended on whether the effect of response slowing was taken into account. The study illustrates an important problem in using the modified spatial cueing task to assess components of threat-related attentional bias. As this experimental method may reflect both threat-related attentional cueing and response slowing effects, it cannot be assumed to provide pure measures of shift or disengagement components of attention bias.