Theories and measurement of visual attentional processing in anxiety

Abstract

Most theoretical models of anxiety disorders implicate maladaptive visuo-spatial attentional processing of threat-relevant information in the onset and maintenance of symptoms. We discuss the central mechanistic hypotheses in clinical science regarding problematic attentional processing of threat in anxiety, reconcile what appear to be contradictory predictions, and integrate those hypotheses to describe comprehensively the overt and covert mechanisms of attentional processing within discrete perceptual episodes. In so doing, we examine critically the prevailing theoretical assumptions and measurement models underlying the current investigations of attention and anxiety, and we advocate for increased precision in the translation of models from vision science to the examination of the mechanisms of attentional processing in anxiety. Finally, we discuss the implications of this approach for future translational research that examines the role of attention in anxiety and its treatment.

Notes

¹Fox and colleagues (e.g., Fox, Russo, Bowles, & Dutton, 2001) generally refer to the hypothesis they advance as the “delayed disengagement” hypothesis. We use “Attention Maintenance” to reflect delayed disengagement as well as the associated mechanism of interest; the mechanism preventing attentional disengagement is the continued maintenance of attention to the threatening stimulus.

²Covert attention can also be used to mark objects and keep track of them (Pylyshyn, 2000).

³It is covert attention to which visual scientists typically (but not always) refer when they use the term “visual attention”.

⁴Given the close relationship between covert attention and eye movements, longer attentional dwell times on threat objects should produce longer fixation durations on those objects.

⁵In the discussed studies (e.g., Calvo & Avero, 2005; Pflugshaupt et al., 2005), inhibition of overt return of gaze to threat (e.g., spider) occurs. Inhibition of covert return of attention to a cued location is also relevant to the current discussion; such inhibition, or IOR, refers to the tendency of the visual system to inhibit return of covert attention to locations (e.g., Posner & Cohen, 1984) or objects (e.g., Tipper, Driver, & Weaver, 1991) that recently have been attended. IOR is evolutionarily adaptive; within a short timeframe, inhibiting attention to a location or object tagged as non-threatening allows more efficient processing of other locations or objects. Interruption of IOR has been shown to occur in response to threat-relevant stimuli in anxious individuals (e.g., Fox, Russo, & Dutton, 2002).

⁶Although researchers have not mapped emotional Stroop task interference onto the VA or AM hypotheses, the Stroop interference effect has been interpreted variously as the maintenance of attention to word meaning or vigilance for threat-relevant word meaning (e.g., Williams, Mathews, & MacLeod, 1996). We agree with recent arguments that the task adequately measures neither, and is primarily of interest only as evidence of more general differential processing of threat in anxiety (Algom, Chajut, & Lev, 2004). Clear interpretation of Stroop results with respect to the subcomponents of attentional processing is limited. The target and distractor stimuli are superimposed in this task, as target colour and distractor word are properties of the same stimulus. From the AM perspective, therefore, it is not possible to determine whether the interference effect reflects facilitated orienting to threat words or difficulty disengaging from them (Fox et al., 2001). In addition, target tasks and threat-relevant stimuli generally are not superimposed spatially in the real world; therefore, this characteristic of the Stroop task limits its generality and its degree of relevance to the research questions of interest (i.e., where attention is allocated in the world), including the examination of vigilance and avoidance as posited by the VA hypothesis.