Effects of the build-up and resetting of auditory stream segregation on temporal discrimination.
The tendency to hear a tone sequence as 2 or more streams (segregated) builds up, but a sudden change in properties can reset the percept to 1 stream (integrated). This effect has not hitherto been explored using an objective measure of streaming. Stimuli comprised a 2.0-s fixed-frequency inducer followed by a 0.6-s test sequence of alternating pure tones (3 low [L]-high [H] cycles). Listeners compared intervals for which the test sequence was either isochronous or the H tones were slightly delayed. Resetting of segregation should make identifying the anisochronous interval easier. The HL frequency separation was varied (0-12 semitones), and properties of the inducer and test sequence were set to the same or different values. Inducer properties manipulated were frequency, number of onsets (several short bursts vs. one continuous tone), tone:silence ratio (short vs. extended bursts), level, and lateralization. All differences between the inducer and the L tones reduced temporal discrimination thresholds toward those for the no-inducer case, including properties shown previously not to affect segregation greatly. Overall, it is concluded that abrupt changes in a sequence cause resetting and improve subsequent temporal discrimination.
Roberts
Brian
B
School of Life and Health Sciences, Aston University.
Glasberg
Brian R
BR
Department of Experimental Psychology, University of Cambridge.
Moore
Brian C J
BCJ
Department of Experimental Psychology, University of Cambridge.
D000161:Acoustic Stimulation / Q000379:methods; D001299:Audiometry; D001307:Auditory Perception; D001309:Auditory Threshold; D004056:Differential Threshold; D004192:Discrimination, Psychological; D006801:Humans; D008960:Models, Psychological; D009146:Music; D010470:Perceptual Masking; D010897:Pitch Discrimination; D011571:Psychoacoustics; D013998:Time Perception