This study aims to investigate the effects of two specific emotions, disgust and fear, which theoretically have similar valence, arousal, and motivational tendencies, on working memory (WM) via the parameters of memory sensitivity and response bias in the Signal Detection Theory (Macmillan & Creelman, 2005). The secondary aim is to assess the effectiveness of the cover story (CS) method, which is commonly employed in experimental laboratory studies of emotion, in an online study. A between-subjects design was employed, with a 2 (CS-present; CS-absent) x 3 (fear, disgust, neutral) factorial structure. 205 participants were randomly assigned to conditions where a CS was either provided or not. The participants were initially induced with fear, disgust, or neutral emotions via emotional film clips. Subsequently, a verbal 2-back task was administered to assess WM performance. In the final stage of the study, participants were asked to complete a form assessing whether they had noticed the true purpose of the CS. The results indicated that fear led to a decrease in memory sensitivity relative to both disgust and the neutral condition. Although the CS did not result in a difference at the self-reported level in comprehension of the study’s true purpose, it indicated a difference in some potentially indirect variables. The results showed that disgust and fear could have specific effects on WM in addition to the dimensions of valence, arousal, and motivational direction. The measurement of the CS also suggested the possibility of measurement with different parameters in addition to self-reporting.
