Musicians routinely infuse their performances with a wide variety of expressive variations, changes in timbre, pitch, dynamics, and timing that are not notated, or at least not precisely specified, in a musical score. These often subtle deviations distinguish human from computer-generated performances and contribute to music's perceived emotionality (Bhatara, Tirovolas, Duan, Levy, & Levitin, 2011). However, the psychological function of expressive variations, and specifically, the manner in which they influence listeners' affective responses to and preferences for music, is still very much a matter of debate (Palmer & Hutchins, 2006).One particular brand of expressive variation that has captured the attention of numerous theorists is the final ritardando, the ubiquitous practice by musicians of decreasing tempo at the close of a musical section or performance. Researchers have noted that the extent of slowing in a given ritardando is associated with the depth within which the boundary that it approaches is embedded in the hierarchical structure of the music (Huron, 2006; Juslin, Friberg, & Bresin, 2002). That is, ritardandi are typically most pronounced at the close of an entire piece or performance, somewhat less pronounced at the close of a major section, and least pronounced at the close of a minor section or phrase boundary. Notably, this phenomenon ostensibly parallels the psycholinguistic tendency for speakers to vary syllable and pause length depending on the structural significance of syntactic boundaries (Palmer & Hutchins, 2006). This had led to speculation that ritardandi are themselves essentially musical syntactic markers (Carlson, Friberg, Fryden, Granstrom, & Sundberg, 1989; Juslin et al., 2002), which reflect the mental representations people form of the hierarchical structure of a musical work, and may be implemented without full voluntary control (Palmer, 1989). According to this view, ritardandi do not necessarily have any direct influence on musical feeling, although in theory, they may heighten the emotional impact of a given musical structure much as the emotional impact of a verbal statement may be intensified to the extent that its processing is facilitated by a clear grammatical structure.A distinct, yet not mutually exclusive, view is based on the notion that ritardandi contribute to the music's emulation of biological motion. Music routinely features many of the auditory cues used to perceive the actions, location, and physical size of realworld objects (London, 2012). To illustrate, the rate of footsteps of an animate entity may be used to estimate how quickly it is moving. The rhythmic pattern of these footsteps may help distinguish between different species (e.g., human vs. nonhuman) or between different forms of motion (e.g., limping vs. skipping). Likewise, variations in the loudness of the footsteps may offer cues to the distance and trajectory of the animate entity vis-a-vis the perceiver's location. The ecological significance of such cues, which form the basis of tempo, rhythmic structure, and dynamics in music, may contribute to listeners experiencing music as a kind of virtual motion in a virtual, acousmatic space . (London, 2012, p. 7).Consistent with this notion, recent studies have offered empirical evidence that music and movement possess similarities in their dynamic structure that enable individuals to readily map variations between the two domains. For instance, Phillips-Silver and Trainor (2005) conducted an experiment in which they exposed mothers and their 7-month-old infants to a metrically ambiguous piece of music. Afterward, mothers were instructed to bounce their children according to either a duple or a triple meter. Finally, infants were exposed to two modified versions of the same music without accompanying movement. These versions were accented so as to either match or mismatch the rhythm to which the infants had originally been bounced by their mothers. …