Attentional bias modi fi cation in social anxiety : E ff ects on the N 2 pc component

Several meta-analyses to date have confirmed the efficacy of attentional bias modification (ABM) in shifting reaction times away from threatening stimuli, reducing anxiety symptoms, and buffering against stressor vulnerability. The reliability of reaction time differences, however, has been found to show unacceptable psychometric properties. In this study, we tested the impact of an extensive Dot-Probe ABM procedure, consisting of close to 7000 trials, concurrently with behavioral and electrophysiological measures within a large sample of over 100 highly socially anxious participants. Results indicated that the N2pc component demonstrates superior internal consistency and more statistical power in detecting attentional biases and their modification than reaction time (RT) differences. RTs were neither indicative of an attentional bias before ABM nor of a modification over time. In contrast, the N2pc indexed both an initial attentional preference for threatening stimuli and an alteration of this relationship after training. Outcomes were not specific for attentional training away from threat but also occurred in the no-contingency control procedure, casting doubt on the theoretic underpinnings of ABM. Electrophysiological measures are an important complement to the ABM literature and should be further utilized to assess attentional biases with excellent reliability. With a lifetime prevalence of almost 30%, anxiety disorders are the most common class of psychopathology in the United States (Kessler et al., 2005). In Europe, 100 million people (i.e., 14% of the population) are affected by anxiety disorders each year (Wittchen et al., 2011). Extensive research on clinical and subclinical samples has established a connection between anxiety and biases in the processing of fear-relevant material (Bar-Haim, Lamy, Pergamin, Bakermans-Kranenburg, & van IJzendoorn, 2007; Koster, Crombez, Verschuere, & Houwer, 2004). Investigations of a causal link between anxiety symptomatology and biased perception already started over 15 years ago (Mathews & MacLeod, 2002). Since then, attentional bias modification (ABM) has been proposed as an efficient enhancing tool for anxiety treatment strategies (Bar-Haim, 2010) and also as a means of prevention due to its potential reduction of anxiety vulnerability (See, MacLeod, & Bridle, 2009). Several meta-analyses to date have confirmed the efficacy of ABM in shifting attentional biases, reducing anxiety symptoms, and buffering against stressor vulnerability (Jones & Sharpe, 2017). However, effects are only small to moderate and symptom reduction seems to be better achieved by modification of interpretative instead of attentional biases. Optimally, ABM is performed on young adults, who are trained in the lab and assessed by a clinician (Jones & Sharpe, 2017; Price et al., 2016). While ABM protocols usually aim to train attention away from threat, recent work has suggested that in a threatening context, e.g. combat deployment of soldiers, ABM toward threat can protect against stress symptoms due to more adaptive threat-monitoring (Shechner & Bar-Haim, 2016). The most prevalent protocol to assess and modify attentional biases is based on the Dot Probe Paradigm (MacLeod, Mathews, & Tata, 1986). Depending on the employed variant, subjects indicate the location or type of a dot stimulus as quickly and accurately as possible. Prior to target presentation, however, two distracting stimuli are shown – one being emotionally relevant and the other comprising a control condition. The attentional bias is then quantified as the difference between the mean response times toward dots co-located with a) the emotional distractors and b) the control category. The psychometric properties of reaction time differences (henceforth “RT bias”) have rarely been investigated. Those researchers who have quantified reliability scores of RT bias, however, found unacceptably low values (Dear, Sharpe, Nicholas, & Refshauge, 2011; https://doi.org/10.1016/j.brat.2019.05.001 Received 24 January 2018; Received in revised form 18 January 2019; Accepted 10 May 2019 ∗ Corresponding author. Department of Psychology I, Julius-Maximilians-University, Marcusstr. 9-11, 97070, Würzburg, Germany. E-mail address: mario.reutter@uni-wuerzburg.de (M. Reutter). Behaviour Research and Therapy 120 (2019) 103404 Available online 11 May 2019 0005-7967/ © 2019 Elsevier Ltd. All rights reserved. T Price, Greven, Siegle, Koster, & Raedt, 2015; Puls & Rothermund, 2017; Reutter, Hewig, Wieser, & Osinsky, 2017; Rodebaugh et al., 2016; Schmukle, 2005; Staugaard, 2009; Van Bockstaele et al., 2011; Waechter, Nelson, Wright, Hyatt, & Oakman, 2014; Waechter & Stolz, 2015), rendering RT bias unsuitable for research on individual differences and thus for differential indication. Possibly due to this unreliability, symptom changes hardly correlate with alterations in RT bias (Jones & Sharpe, 2017). According to the very core idea that modification of attentional biases induce these symptom changes, however, such an association should be present. If the problem does not lie within the validity of the theoretic construct, other operationalizations of attentional bias might be better suited to reveal the connection between biased processing and anxiety. For example, eye-movements have shown tremendously better reliability than reaction time differences in a dot probe task (Waechter et al., 2014) but also showed little association with anxiety symptoms. Neural measures usually dominate reaction time differences with respect to their reliability as well (Kappenman, Farrens, Luck, & Proudfit, 2014; Kappenman, MacNamara, & Proudfit, 2015; Reutter et al., 2017; White et al., 2016). While they are not correlated with scores of general trait anxiety (Kappenman et al., 2014), they do show an association with measures of specific anxiety (Reutter et al., 2017). Among assessments of brain activity, the N2pc component in the EEG is a promising signal for applications within a Dot Probe Paradigm due to its potential to reveal deployment of spatial attention (Eimer, 1996; Luck & Hillyard, 1994). The N2pc also occurs automatically and is therefore well suited to index attentional affordance of task-irrelevant stimuli (Eimer & Kiss, 2007; Fenker et al., 2010). More specifically, it is supposed to reflect selective visual processing but not attentional shifts (Kiss, van Velzen, & Eimer, 2008). Using facial stimuli, the N2pc is more pronounced when attending to angry compared to happy (FeldmannWüstefeld, Schmidt-Daffy, & Schubö, 2011) or neutral (Weymar, Löw, Ohman, & Hamm, 2011) expressions, especially if subjects are highly anxious (Fox, Derakshan, & Shoker, 2008; Wieser, Hambach, & Weymar, 2018). Recently, the N2pc has been successfully utilized as an index of attentional bias within a Dot Probe Paradigm, demonstrating higher statistical power and greater reliability than reaction time differences (Kappenman et al., 2014, 2015; Reutter et al., 2017). It has also been employed to assess the impact of a one-session attentional bias modification training (Osinsky, Wilisz, Kim, Karl, & Hewig, 2014). In the current study, we aimed to investigate the efficacy of an extensive attentional bias modification procedure concurrently via behavioral and electrophysiological measures (i.e., reaction time differences and the N2pc, respectively) in a highly socially anxious but undiagnosed sample. We hypothesized that subjects in the training condition show greater reductions of attentional bias than control participants and that these changes are more pronounced in the N2pc than in reaction times. The cross-sectional data prior to training including a correlational analysis of attentional bias measures and questionnaire data have been reported elsewhere (Reutter et al., 2017).