Post on 19-Dec-2015
transcript
Temporal processingRepresentation of the temporal
characteristics of sound
Temporal variation in sound carries important information
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Different measures of temporal processing mature at different rates Gap detection Duration discrimination Forward and backward masking Temporal modulation transfer function
Gap detection
Time (ms)
Lev
el (
dB
)
Time (ms)
Lev
el (
dB
)
Interval 1 Interval 2
Which one had a gap?
Gap detection for infants
Time (ms)
Lev
el (
dB
)
Adult gap detection depends on frequency
Gap detection by infants: Werner et al. (1992)
Frequency (Hz)
Leve
l (dB
)
Time (ms)
Lev
el (
dB
)
Time (ms)
Lev
el (
dB
)
Gap detection by infants: Werner et al. (1992)
Gap detection by children: Irwin et al. (1985)
Gap detection by children: Wightman et al. (1988)
Detecting gaps between Gaussian shaped tone bursts
Gap detection between Gaussian shaped tone bursts
Summary of gap detection
Duration discrimination
Susceptibility to adaptation
Adaptation
Recovery
Susceptibility to adaptation
Forward masking as a measure of susceptibility to adaptation
Adaptation
Recovery
TimeAm
plitu
de
Forward masking: Infants
Forward masking: Children
Backward masking
TimeAm
plitu
de
Backward masking: Infants
0.5
0.6
0.7
0.8
0.9
1
15 25 35 45 55 65 75 85 95
p(C
)
Level (dB SPL)
Infants
Adults
Infant unmaskedthreshold
adult unmaskedthreshold
Backward masking: Children
Amplitude modulation: frequency and depth
-1.5
-1
-0.5
0
0.5
1
1.5
0 0.05 0.1 0.15Time (s)
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
0 0.05 0.1 0.15
-1.5
-1
-0.5
0
0.5
1
1.5
0 0.05 0.1 0.15
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
0 0.05 0.1 0.15
10 Hz10 Hz
20 Hz
100%, 0 dB 25%, -12 dB
Temporal modulation transfer function
TMTF: Infants
0
-5
-10
-15
-20
-25
1 10 100 512
Mod
ulat
ion
dept
h, 2
0 lo
g m
(dB
)
Modulation frequency (Hz)
adults
3-month-olds6-month-olds
TMTF: Children
Summary of results on different measures Gap detection: mature at 6 years Duration discrimination: mature at 10 years Forward masking: mature at 6 months Backward masking: mature at 11 years TMTF: mature at 4 years (3 months?)
SummaryThere doesn’t seem to be one age at
which all sorts of temporal processing are mature
Possible additional contributors to immature temporal processing Intensity resolution Memory Confusion Decision strategy