What kind of mood influences what kind of memory: The role of arousal and information structure

Mood-congruent memory was investigated as a function of the structure of the information to be remembered (categorical vs. isolated) and the participant’s arousal (stimulating drug vs. placebo). Free recall of photographs showing either pleasant or unpleasant scenes was assessed for subjects under positive or neutral mood states, induced by the imagination of emotional experiences under relaxation. Although the arousal manipulation did not affect the recall performance, the findings highlight the importance of the information structure: a mood-congruency effect was obtained for the isolated pictures; however, the effect did not appear for categorical material, suggesting that structural constraints on the recall process can override the influence of mood on memory. Interestingly, the subject’s evaluations of the pictures also shifted toward their mood states. A general recall advantage of positive mood was observed.