Sound source segregation
Development of the ability to separate concurrent sounds into
auditory objects
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)
Electrophysiological measures of streaming in children
Electrophysiological measures of streaming in children
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)
Preferential looking procedure
baseball, baseball, baseball
(“Twenty subjects were tested…”)
baseball, baseball, baseballpopcorn, popcorn, popcorn
Testing whether children can segregate speech from speech
Ready Baron go to Blue 3 nowReady Ringo go to Red 5 now
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.
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.