Auditory discrimination of tone-pulse onsets

Area of Science:

• Psychoacoustics
• Auditory perception
• Signal processing

Background:

• Understanding auditory perception of temporal envelope cues is crucial.
• Previous research on difference limens (DLs) has explored various acoustic parameters.
• The perception of tone onset times, specifically rise times, requires further investigation.

Purpose of the Study:

• To measure difference limens (DLs) for the onset times of a 1000-Hz tone pulse.
• To investigate whether rise times are perceived categorically.
• To compare DLs across different onset envelope shapes.

Main Methods:

• Two experiments utilizing an adaptive two-alternative forced-choice procedure with trained subjects.
• Experiment 1: Measured DLs for linear onset ramps (10-60 msec rise times).
• Experiment 2: Measured DLs for linear, exponential, and raised-cosine envelopes (10-40 msec rise times).

Main Results:

• DLs for linear rise times followed Weber's law up to approximately 50 msec.
• Results did not support the hypothesis of categorical perception for rise times.
• Equivalent intensity DLs for discriminable onsets showed "near miss to Weber's law" behavior, similar to pure tones.

Conclusions:

• Auditory perception of tone onset rise times adheres to Weber's law within a certain range.
• The perception of rise times is not categorical.
• Temporal envelope processing in auditory perception exhibits characteristics similar to intensity processing.