Whether we're deciding to return to a restaurant or to purchase a DVD, many consumers rely on memory when they're making decisions.

A new study in the Journal of Consumer Research examines the role of mood on those memory-based decisions.

"Further imagine that you went into the restaurant either in a good or bad mood, perhaps because it was a rainy or sunny day. A week later, would you be more likely to praise the restaurant or return to it if your earlier experience happened on a sunny day?"

The researchers found that "incidental mood" is generally not incorporated into memory-based judgments made after the mood has passed. In other words, your memory of the restaurant's food won't be affected by the mood you were in when you ate it. However, this changes if the mood effects are "locked in"—for example, if you respond to a question about how much you are enjoying the meal.

In one study, the researchers examined the effect of participants' moods on their evaluations of a painting. A negative mood was induced in some participants by having them read a story and answer questions about inhumane treatment of pregnant horses. Then half of the participants were asked to provide "real-time evaluations" of the painting while others just went home.

Five days later, all participants were contacted via email and asked to rate how much they would enjoy having a poster of the painting in their homes. Participants in a negative mood rated the painting lower in real time, and participants who did not make a real-time evaluation showed no effect of mood at the later time.

Source: University of Chicago Press Journals