Book Description

Rhythmicity is a key component that allows humans to attend to, predict, and respond to the environment. In particular, temporal processing is fundamental to the perception and production of complex sounds, such as speech and music. Neural entrainment hypothesizes that internal oscillators synchronize with external stimuli, providing a unified mechanism for supramodal temporal processing. Extensive research demonstrates the entrainment effect on human time perception for non-speech musical sounds; fewer studies have shown entrainment effects for duration perception in spoken language. To date, it remains unclear how humans encode temporal properties and generate rhythm according to them, and whether and how entrainment mechanisms represent timing information in the brain. My aim is to address these important open questions. In Chapter 1 of my thesis, I reviewed the existing literature and gaps therein. Chapter 2 compared whether entrainment or interval models more accurately predict human time perception. Entrainment models more accurately predicted duration discrimination, but the effect diminished after 2-4 cycles, while interval models predicted more accurately thereafter. Chapter 3 tested entrainment effects on more ecologically valid contexts--speech sounds, and found that entrainment can transfer from tones to speech sounds, suggesting a domain-general entrainment effect with a constraint by acoustical similarity. Chapter 4 examined neural evidence of entrainment in hierarchically organized drumming rhythm. The study found that both auditory and motor regions represent the rhythms imagined by the subjects. A motor-to-auditory information flow was found in all listening conditions without overt movements, suggesting that the motor system actively maintains hierarchical information and exerts a top-down influence on auditory processing and metrical imagery of rhythms. Chapter 5 further investigated rhythm production using self-paced tapping and synchronization, finding that synchronization relies on auditory-motor interaction in beta-band, only observed in individuals who tap relatively stably in the self-paced tapping task without external cues. In summary, this thesis work contributes to the theoretical understanding of how humans perceive, imagine and produce temporal events, particularly in a rhythmic context, at the behavioral and neural levels. My hope is that this work can improve real-life applications and inform work with clinical populations who have timing-related deficits.