How do moods, motivations, and prior experiences alter perceptions? For instance, is there likely to be a difference in your perceptions when you go to the grocery store when you are hungry and then after you have just eaten? Or reactions to other drivers on the road when you are in a good mood versus when you are in a bad mood? Or did you ever disagree with someone about what happened at an event you both attended? How does this apply to mistakes in eye witness testimony? For example, a 1998 study found that of 40 convictions that were later overturned, in 36 the eyewitnesses had confidently identified the wrong person as the perpetrator. What factors do you think could bias witnesses' perceptions?