In this study, researchers first selected five female and five male subjects who had at least eight years of music training. This aspect was viewed as crucial because researchers surmised that this population would have a "strong emotional response" to music.
Each participant self-selected a piece of music that elicited "chills," or an intensely pleasant emotional response. Since musical preferences are highly individual, this was an important factor in order to elicit the anticipated response. Interestingly, all participants chose classical pieces without any words, reporting that their response was dependent on the music itself rather than any particular association or memory. Each participant's selected music was also used as another participant's control music, eliciting a neutral emotional response.
PET scans were then performed during 60-second intervals based on four different types of stimuli. Participants listened to self-selected music, emotionally neutral music (which was the music that elicited "chills" for another participant), amplitude-matched noise, and silence. Each of these conditions was repeated three times, and the order the stimulus was presented was randomized.
Data was recorded on various physiological responses during these intervals. Participants' heart rate, electromyogram, respiration depth, electrodermal response, and skin temperature were recorded during the PET scans. After each scan, each participant rated his emotional reaction to each stimulus using three different categories: the intensity of "chills" (on a scale of 0 to 10), the emotional intensity (on a scale of 0 to 10), and whether the experience was overall unpleasant or pleasant (-5 to +5 scale).