Dave Munger has a good post up about a study on the effect of tempo and mode (major or minor) on the perception of emotion. I offer some criticism, however. Emotion was limited to happy and sad, which is far simpler than the most-used models of emotion in psychology. This will skew the results when multidimensional responses are forced into a two-choice response.
This study reminds me of a paper given at the Leipzig conference last spring. Emmanuel Bigand and his team decided to investigate how quickly people identify the emotion of a musical work. They made 27 musical excerpts one second in duration, and asked participants to group the works by their emotional similarity. There was a high degree of agreement between subjects and within subjects, even with this very short time period. In fact, the results even agreed with a similar experiment using 25-second excerpts, suggesting that 1 second is enough to convey emotional content. Emboldened by these results, Bigand's team had participants evaluate how emotionally moving a variety of excerpts were on a 10 point subjective scale. These excerpts started as only 250 milliseconds. Next, the participants judged the same excerpts, but they were extended to 500 ms, and then 1, 2, 5, and 20 seconds. Incredibly, some judgements were consistent from the 250 ms duration through the 20 second duration, meaning that the listeners made the judgments of emotional affect in very short time periods.
As a tangent, Emmanuel Bigand has an interesting Shockwave animation of Chopin's Prelude in E major. While it is a serious explication of the cognitive significances of Fred Lerdahl's Tonal Pitch Space, it's also plain old fun to watch. Zoom out to get the big picture, or zoom in to watch the movement among the "moons".
E. Bigand, "The Time course of emotional responses to music," paper presented at The Neurosciences and Music - II conference in Leipzig, Germany on May 7, 2005.