Effects of anxiety on children's working memory

Processing efficiency theory accounts for the effect of state anxiety on working memory (WM) performance. It postulates that adverse effects of anxiety are more pronounced on processing efficiency (e.g., effort) than on performance effectiveness (e.g., accuracy). Most studies evaluating this theory use normal adult samples and do not consider possible effects of learning disabilities (LD) and attention-deficit/hyperactivity disorder (ADHD). No studies exist that directly evaluate this theory in clinically anxious children. Study 1 Objective. To test predictions of processing efficiency theory on clinically anxious children---taking into account comorbid LD and ADHD---across the multiple components of the WM system. It was hypothesized that compared to typically developing children, anxious children would have comparable accuracy (performance effectiveness), but obtain slower response times and report more effort (processing efficiency) on WM measures assessing the phonological loop and central executive. Study 1 Method. Anxious and typically developing children (7-12 years) were recruited; those who screened positively for LD or ADHD were excluded. The anxiety group (n=18) and normal control group (n=23) were administered a test battery which assessed the multiple components of WM. Study 1 Results. The anxiety group did not differ significantly from the control group on accuracy, response times, or reported effort on all WM measures. Study 2 Objective. A post-hoc study was added given the challenges to interpretation of the null findings in Study 1. An ADHD group was added as a clinical comparison to show that WM accuracy was not impaired in the anxiety and control groups in Study I, and that our tests are sensitive to WM impairments. Study 2 Method. The ADHD group (n=10) received the same WM assessment as in Study 1. ADHD accuracy, response times, and subjective effort were compared to Study I anxiety and control group WM data. Study 2 Results. The ADHD group obtained lower accuracy on Word Recall and Spatial Working Memory than the control group. The anxiety, ADHD, and control groups did not differ significantly on response times or reported effort. Conclusion. Processing efficiency theory does not predict WM outcomes of 'purely' trait-anxious children when state anxiety is not activated. Future research may replicate this study using a stressful condition to induce state anxiety. Educational and clinical implications for the absence of WM impairments in purely anxious children are discussed.