Presentation on theme: "Sound source segregation Development of the ability to separate concurrent sounds into auditory objects."— Presentation transcript:
Sound source segregation Development of the ability to separate concurrent sounds into auditory objects
The problem… TIME FREQUENCY Wow! Psychophysics is interesting!
Cues that adults use to segregate components into sources Spectral separation Spectral profile Harmonicity Spatial separation Temporal separation Temporal onsets and offsets Temporal modulations
Measuring sound source segregation Auditory streaming “Thresholds” of sounds, segregated and not segregated Informational masking (indirect evidence)
A single sound source is perceived
Two sound sources are perceived
Auditory streaming in infants How many streams that time?
Auditory streaming in infants
Configuration 3/1 Configuration 2/2
Electrophysiological measures of streaming in newborns
Auditory streaming in children
Another way to look at auditory streaming in children
Electrophysiological measures of streaming in children
Conclusion Infants and children form “auditory streams.”
Thresholds of sound, segregated and not segregated Spatial cues Synchronized visual information
Masking level difference The MLD is the improvement in audibility that results from dichotic listening N= noise, S = signal Monotic = one ear (m) Diotic = 2 ears, same sound in both (0) Dichotic = 2 ears, different sound in each (π) Modified from Gelfand (1998)
Visual information improves speech in speech recognition in infants
Testing whether children can segregate speech from speech Ready Baron go to Blue 3 now Ready Ringo go to Red 5 now
Visual information doesn’t improve speech in speech recognition in children
Conclusions Infants and children are more sensitive to sounds that can be segregated from competing sounds, although infants show less benefit of segregation cues. Under simple conditions, even 3-year-olds can use segregation cues as well as adults. Under complex conditions, even 10-year-olds do not use segregation cues as well as adults.
Informational masking? Interval 2 Level Frequency Trial Interval 1
Using temporal cues to reduce informational masking
Summary and conclusions Infants and children can segregate sound sources, using the same acoustic cues that adults use. In simple situations, children, but not infants, can segregate sound sources as well as adults. In complex situations, sound source segregation may not be mature until well into the school years.