  Jazz music that swings has the fascinating power to elicit a pleasant
sensation of flow in listeners and the desire to synchronize body movements
with the music. Whether microtiming deviations (MTDs), i.e. small timing
deviations below the bar or phrase level, enhance the feeling of swing is
highly debated in the current literature. Studies on other groove related
genres did not find evidence for a positive impact of MTDs. The present study
addresses jazz music and swing in particular, as there is some evidence that
microtiming patterns are genre-specific. We recorded twelve piano jazz
standards played by a professional pianist and manipulated the natural MTDs of
the recordings in systematic ways by quantizing, expanding and inverting them.
MTDs were defined with respect to a grid determined by the average swing ratio.
The original and manipulated versions were presented in an online survey and
evaluated by 160 listeners with various musical skill levels and backgrounds.
Across pieces the quantized versions (without MTDs) were rated slightly higher
and versions with expanded MTDs were rated lower with regard to swing than the
original recordings. Unexpectedly, inversion had no impact on swing ratings
except for two pieces. Our results suggest that naturally fluctuating MTDs are
not an essential factor for the feeling of swing.
