Dominique Lamy

Threat-Related Attentional Bias in Anxious and Nonanxious Individuals: A Meta-Analytic Study

This meta-analysis of 172 studies (N = 2,263 anxious,N = 1,768 nonanxious) examined the boundary conditions of threat-related attentional biases in anxiety. Overall, the results show that the bias is reliably demonstrated with different experimental paradigms and under a variety of experimental conditions, but that it is only an effect size of d = 0.45. Although processes requiring conscious perception of threat contribute to the bias, a significant bias is also observed with stimuli outside awareness. The bias is of comparable magnitude across different types of anxious populations (individuals with different clinical disorders, high-anxious nonclinical individuals, anxious children and adults) and is not observed in nonanxious individuals. Empirical and clinical implications as well as future directions for research are discussed.

Attentional bias in anxiety: A behavioral and ERP study

Accumulating evidence suggests the existence of a processing bias in favor of threat-related stimulation in anxious individuals. Using behavioral and ERP measures, the present study investigated the deployment of attention to face stimuli with different emotion expressions in high-anxious and low-anxious participants. An attention-shifting paradigm was used in which faces with neutral, angry, fearful, sad, or happy expressions were presented singly at fixation. Participants had to fixate on the face cue and then discriminate a target shape that appeared randomly above, below, to the left, or right of the fixated face. The behavioral data show that high-anxious participants were slower to respond to targets regardless of the emotion expressed by the face cue. In contrast, the ERP data indicate that threat-related faces elicited faster latencies and greater amplitudes of early ERP components in high-anxious than in low-anxious individuals. The between-group pattern in ERP waveforms suggests that the slower reaction times in high-anxious participants might reflect increased attentional dwelling on the face cues, rather than a general slowing of response enacting.

Integration Without Awareness Expanding the Limits of Unconscious Processing

Human conscious awareness is commonly seen as the climax of evolution. However, what function—if any—it serves in human behavior is still debated. One of the leading suggestions is that the cardinal function of conscious awareness is to integrate numerous inputs—including the multitude of features and objects in a complex scene—across different levels of analysis into a unified, coherent, and meaningful perceptual experience. Here we demonstrate, however, that integration of objects with their background scenes can be achieved without awareness of either. We used a binocular rivalry technique known as continuous flash suppression to induce perceptual suppression in a group of human observers. Complex scenes that included incongruent objects escaped perceptual suppression faster than normal scenes did. We conclude that visual awareness is not needed for object-background integration or for processing the likelihood of an object to appear within a given semantic context, but may be needed for dealing with novel situations.

Attentional capture in singleton-detection and feature-search modes.

Six experiments were conducted to determine the circumstances under which an irrelevant singleton captures attention. Subjects searched for a target while ignoring a salient distractor that appeared at different stimulus onset asynchronies (SOAs) prior to each search display. Spatial congruency and interference effects were measured. The strategies available to find the target were controlled (only singleton-detection mode, only feature-search mode, or both search strategies available). An irrelevant abrupt onset captured attention in search for a color target, across SOAs, whatever strategies were available. In contrast, in search for a shape target, an irrelevant color singleton captured attention in the singleton-detection condition but delayed response at its location in the feature-search condition, across SOAs. When both strategies were available, capture was short lived (50- to 100-msec SOAs). The theoretical implications of these findings in relation to current views on attentional capture are discussed. ((c) 2003 APA, all rights reserved)

Effects of Task Relevance and Stimulus-Driven Salience in Feature-Search Mode.

Attentional allocation in feature-search mode (W. F. Bacon & H. E. Egeth, 1994) is thought to be solely determined by top-down factors, with no role for stimulus-driven salience. The authors reassessed this conclusion using variants of the spatial cuing and rapid serial visual presentation paradigms developed by C. L. Folk and colleagues (C. L. Folk, R. W. Remington, & J. C. Johnston, 1992; C. L. Folk, A. B. Leber, & H. E. Egeth, 2002). They found that (a) a nonsingleton distractor that possesses the target feature produces attentional capture, (b) such capture is modulated by bottom-up salience, and (c) resistance to capture by irrelevant singletons is mediated by inhibitory processes. These results extend the role of top-down factors in search for a nonsingleton target while arguing against the notion that effects of bottom-up salience and top-down factors on attentional priority are strictly encapsulated within distinct search modes.

Object-based selection: The role of attentional shifts

The objective of this paper was to investigate under what conditions object-based effects are observed. Recently, Watson and Kramer (1999) used a divided-attention task and showed that unless top-down factors induce a bias toward selection at a higher level, object-based effects are obtained when same-object targets belong to the same uniformly connected (single-UC) region, but not when they belong to different single-UC regions grouped into a higher order object (grouped-UC regions).We refine this claim by proposing that a critical factor in determining whether or not object-based effects with grouped-UC regions are observed is the need to shift attention. The results of four experiments support this hypothesis. Stimuli and displays were similar to those used by Egly, Driver, and Rafal (1994). Subjects had to make size judgments. Using different paradigms, we obtained object-based effects when the task required shifts of attention (spatial cuing, same vs. different judgment with asynchronous target onsets), but not when attention remained either broadly distributed (same vs. different judgment with simultaneous targets) or tightly focused (response competition paradigm).

Enhanced neural reactivity and selective attention to threat in anxiety

Attentional bias towards threat is implicated in the etiology and maintenance of anxiety disorders. We examined the neural correlates of threat bias in anxious and nonanxious participants to shed light on the neural chronometry of this cognitive bias. In this study, event-related potentials (ERPs) were recorded while anxious (n=23) and nonanxious (n=23) young adults performed a probe-discrimination task measuring attentional bias towards threat (angry) and positive (happy) face stimuli. Results showed an attention bias towards threat among anxious participants, but not among nonanxious participants. No bias to positive faces was found. ERP data revealed enhanced C1 amplitude (∼80 ms following threat onset) in anxious relative to nonanxious participants when cue displays contained threat faces. Additionally, P2 amplitude to the faces display was higher in the anxious relative to the nonanxious group regardless of emotion condition (angry/happy/neutral). None of the ERP analyses associated with target processing were significant. In conclusion, our data suggest that a core feature of threat processing in anxiety lies in functional perturbations of a brain circuitry that reacts rapidly and vigorously to threat. It is this over-activation that may set the stage for the attention bias towards threat observed in anxious individuals.

Neural correlates of subjective awareness and unconscious processing: An erp study

The aim of the present study was to dissociate the ERP (Event Related Potentials) correlates of subjective awareness from those of unconscious perception. In a backward masking paradigm, participants first produced a forced-choice response to the location of a liminal target presented for an individually calibrated duration, and then reported on their subjective awareness of the targets presence. We recorded (Event-Related Potentials) ERPs and compared the ERP waves when observers reported being aware vs. unaware of the target but localized it correctly, thereby isolating the neural correlates of subjective awareness while controlling for differences in objective performance. In addition, we compared the ERPs when participants were subjectively unaware of the targets presence and localized it correctly versus incorrectly, thereby isolating the neural correlates of unconscious perception. All conditions involved stimuli that were physically identical and were presented for the same duration. Both behavioral measures were associated with modulation of the amplitude of the P3 component of the ERP. Importantly, this modulation was widely spread across all scalp locations for subjective awareness, but was restricted to the parietal electrodes for unconscious perception. These results indicate that liminal stimuli that do not affect performance undergo considerable processing and that subjective awareness is associated with a late wave of activation with widely distributed topography.

When time slows down: The influence of threat on time perception in anxiety

Here, we explored the effect of exposure to threat versus neutral stimuli on time perception in anxious (n=29) and non-anxious (n=29) individuals using predictions from the attentional gate model (AGM) of time perception. Results indicate that relative to non-anxious individuals, anxious individuals subjectively experience time as moving more slowly when exposed to short (2-second) presentations of threat stimuli, and that group differences disappear with longer exposure durations (4 and 8 seconds). Coupled with classic reports of enhanced attentional bias toward threat and diminished attentional control under stress in anxious individuals this finding provides novel insights into low-level cognitive processes that could shape and maintain the subjective experience of anxiety. Findings are discussed in relation to predictions from the AGM and cognitive accounts of anxiety.

Priming of Pop-out provides reliable measures of target activation and distractor inhibition in selective attention☆

Recent research has demonstrated a striking role for intertrial priming in visual search. When searching for a discrepant target, repetition of the target feature speeds search, an effect known as Priming of Pop-out (PoP). In two experiments involving color singletons, we identified two independent components of PoP, target activation and distractor inhibition. Each component was reflected by two measures, a repetition benefit and a switching cost, that were highly correlated. Large individual differences on each component were observed and persisted when test and retest were separated by one week. The results suggest that PoP may be a reliable tool for assessing individual differences on target activation and distractor inhibition in selective attention.