Low working memory load facilitates attention bias modification training

Implementations of attention bias modification training (ABMT) attempt to retrain attention away from rather than towards threat, thereby disrupting the anxiety-related attentional bias (AB). Yet, results of ABMT studies have been mixed due to limitations in knowledge of mechanisms underlying ABMT efficacy. Dual-process models of anxiety posit that ABMT works primarily through strengthening of the top-down cognitive control of attention to threat. If this is the case, introducing a working memory load (WML) during ABMT should reduce training efficacy. However, prior studies employing this method show mixed results (Booth, Mackintosh, Mobini, Oztop, & Nunn, 2014; Clarke et al., 2017) and fail to directly compare low and high WML with no WML or to account for individual differences in anxiety and working memory capacity (WMC). The present study (N = 306) assessed trait anxiety and WMC in neurotypical adults who were then randomly assigned to ABMT that trained attention toward or away from threat, with either no, low, or high WML, for a total of six training groups. Attentional bias was assessed before and after training. Results showed ABMT successfully trained attention under low WML, but not under high or no WML, suggesting that ABMT is facilitated by engaging but not overtaxing WML.