BEAT AND METER INDUCTION ARE CONSIDERED impor-

tant structuring mechanisms underlying the perception of rhythm. Meter comprises two or more levels of hier-archically ordered regular beats with different periodic-ities. When listening to music, adult listeners weight events within a measure in a hierarchical manner. We tested if listeners without advanced music training form such hierarchical representations for a rhythmical sound sequence under different attention conditions (Attend, Unattend, and Passive). Participants detected occasional weakly and strongly syncopated rhythmic patterns within the context of a strictly metrical rhyth-mical sound sequence. Detection performance was bet-ter and faster when syncopation occurred in a metrically strong as compared to a metrically weaker position. Compatible electrophysiological differences (earlier and higher-amplitude MMN responses) were obtained when participants did not attend the rhythmical sound sequences. These data indicate that hierarchical repre-sentations for rhythmical sound sequences are formed preattentively in the human auditory system