The data demonstrated numerous examples where the subjects modulated their natural respiration cycles in order to reflect phrasing and character in the music. This modulation may or may not have been conscious and purposeful, and may also have been influenced by the motions of their arms, but nonetheless seems significant and highly correlated with the expressive qualities in the music. For example, P1’s breathing correlated more closely with the phrasing in the music than that of any other subject. In one musical section, P1’s respiration cycles matched the metrical cycles of the music; when the meter changed, so did his breathing patterns. Secondly, his respiration signal often increased in anticipation of a downbeat and sharply decreased right afterward. This might have been the result of the compression of the ribcage in the execution of the beat, but could also be an intentionally expressive phenomenon. For example, it is considered a standard practice among conductors to breathe in at upbeats and breathe out at downbeats, regulating their flow of air relative to the speed and volume of the music.
Similarly, P3’s breathing showed a very tight correlation with his beat gestures – during loud, active, regular passages (such as during Sousa’s Washington Post March, that began his program), the respiration signal seemed to correspond directly with the beats. It is not clear, however, what the causes and responses are, and whether this is a case of arm motion completely dictating the movement of the ribcage, or conscious breathing with the beats. It could be that a major part of the respiration signal is caused by motion artifact from the movement of the arms, but often this can be refuted from the data.