The hypothesis that stimuli agreeing in affective valence with one’s mood are learned and retrieved better than stimuli of different valence.
The enhanced encoding and/or retrieval of material the affective valence of which is congruent with ongoing mood.
Matt, G. E., Vázquez, C., & Campbell, W. K. (1992). Mood-congruent recall of affectively toned stimuli: A meta-analytic review. Clinical Psychology Review, 12(2), 227-255. doi: 10.1016/0272-7358(92)90116-P.
Blaney, P.H. (1986). Affect and memory: A review. Psychological Bulletin, 99(2), 229-246. doi: 10.1037/0033-2909.99.2.229