Metric strength directs a patterned allocation of attention across time

Ahren Fitzroy – Neuroscience and Behavior Program, University of Massachusetts, Amherst

Talk presented at the annual New England Sequencing and Timing meeting, Amherst, MA

Selectively attending to portions of an incoming sensory stream based on certain distinguishing aspects can help us make sense of what would otherwise be overwhelming amounts of information.  Previous research on selective attention has largely focused on the use of spatial selection, but recent evidence demonstrates that people also use time of stimulus presentation as an attentional selection criterion.  Event-related brain potential (ERP) research has shown that temporally selective attention affects early perceptual processing as indexed by the amplitude of the first negative peak 100 ms after sound onset (N1) in a manner similar to that observed for spatially selective attention.  Further, physically identical stimuli elicit larger amplitude N1s when presented at times of metric strength in both stimulus-inherent and listener-imposed metric hierarchies, suggesting that metric structure guides the allocation of attention across time.  These findings are consistent with the predictions of Dynamic Attending Theory (DAT).  Multiple oscillator variants of DAT predict that hierarchically organized exogenous rhythms will induce a hierarchical distribution of attention across time; the present studies employ subject-initiated hierarchical rhythmic structures to test this hypothesis.  Larger amplitude N1s were elicited by tones on the first beat of subjective measures, suggesting a global attentional preference for downbeats.  Differences in N1 amplitude among non-downbeats indicate that attention is not equally distributed among weaker beats, and suggest attention may be allocated in a hierarchical manner during quaternary meter perception.  These results indicate that metric structure guides the allocation of attention across time in a patterned manner as predicted by DAT.

Auditory stimuli presented during talk:

Short melody example

Isochronous beep stream example