MUSIC ELICITS PROFOUND EMOTIONS; HOWEVER, THE time-course of these emotional responses during listening sessions is unclear. We investigated the length of time required for participants to initiate emotional responses ("integration time") to 138 musical samples from a variety of genres by monitoring their real-time continuous ratings of emotional content and arousal level of the musical excerpts (made using a joystick). On average, participants required 8.31 s ( SEM = 0.10) of music before initiating emotional judgments. Additionally, we found that: 1) integration time depended on familiarity of songs; 2) soul/funk, jazz, and classical genres were more quickly assessed than other genres; and 3) musicians did not differ significantly in their responses from those with minimal instrumental musical experience. Results were partially explained by the tempo of musical stimuli and suggest that decisions regarding musical structure, as well as prior knowledge and musical preference, are involved in the emotional response to music.