Phase resetting and rhythmic performance

Both music and speech are transmitted primarily by sound, and both can be characterized as rhythmic. When people hear a regular series of sounds, they are able to “follow” it much better than they can a similar series of flashing lights, whether this involves synchronizing overt movements with the series, or merely counting. A possible explanation for this morality difference is that sounds, but not lights, have a strong automatic phase resetting influence on an internal timing process, or clock, that underlies rhythmic perception and production. Experimental evidence supporting this hypothesis will be presented. Phase-dependent phase resetting, as found in circadian systems, neural pattern generators, and electronic phase-locked loops, ensures entrainment of an endogenous rhythmic process to an exogenous one, and resetting of a central timer by feedback from movements it controls reduces their variability. The operation of such automatic resetting processes in human rhythmic performance suggests explanations for a great many facts about time perception, temporal numerosity judgments, auditory feedback, and other phenomena. The possible relevance of some of these to speech and music will be discussed.