Positive for verbal, negative for visual? Processing of affective stimuli in verbal and visual working memory (dataset and script)

There is an assumption about emotions and WM that verbal WM functions better under positive emotional influence while visuospatial WM functions better under negative emotional influence. We tested whether positive stimuli were processed faster than negative in the verbal 2-back while negative stimuli were processed faster in the visual 2-back. 137 undergraduates participated in a study with 2-back task with positively and negatively valenced stimuli in visual and verbal modality. Many confounds not typically controlled for in emotion/WM studies were controlled. There was a clear valence effect in the verbal WM task for RT in target trials (positive words processed faster than negative), and no valence effect in the visual WM task. The valence effect in verbal WM was produced by negative words processed more slowly. The analysis of individual RT distributions via ex-Gaussian models has shown that positive stimuli are processed faster than negative ones (automatic processing), but this effect is masked by longer right tails of RT distribution. Accuracy analysis based on signal detection theory revealed that negative verbal stimuli are processed more cautiously compared to visual ones. These findings align well with the dual competition theory of emotional stimuli processing.