Mood images from the International Affective Picture System (IAPS; Lang et al., 1999) were chosen based on developmental ratings of valence and arousal provided by Lang and colleagues (1999). Participants then viewed three sample images (one from each mood condition) that were similar to those that they would see during imaging. Three image groups were formed (mean values taken from developmental ratings): neutral images (mean valence = 5.11, mean arousal = 3.28), negative images (mean valence = 2.55, mean arousal = 5.55), and positive images (mean valence = 6.94, mean arousal = 5.78).
