Simple reaction time for broadband sounds compared to pure tones

Area of Science:

• Auditory Perception
• Psychoacoustics
• Acoustics

Background:

• Reaction time (RT) studies typically use pure tones, yet real-world sounds are broadband.
• Spectral summation effects on RT are less understood compared to intensity and frequency.
• Standardized loudness measurements require understanding responses to complex sounds.

Purpose of the Study:

• To compare reaction times (RTs) for broadband noise against 1-kHz pure tones.
• To investigate spectral loudness summation using different noise bandwidths and center frequencies.
• To examine binaural summation for broadband sounds.

Main Methods:

• Three experiments were conducted comparing RTs for various spectral and binaural configurations.
• Pink noise (full-range and bandpass-filtered) and white noise were used.
• Measurements were taken across different sound pressure levels.

Main Results:

• Experiments 1 & 2 showed good agreement with spectral loudness summation models for moderate to high sound pressure levels.
• At lower levels, RTs revealed a level-bandwidth interaction not seen in loudness scaling.
• Experiment 3 found a binaural gain of 9 dB for white noise, exceeding previous pure-tone findings.

Conclusions:

• Spectral loudness summation models partially explain RTs for broadband noise, particularly at higher levels.
• Discrepancies at lower levels highlight the need to consider bandwidth effects in RT and loudness perception.
• Binaural summation for broadband noise appears greater than for pure tones, suggesting differences in auditory processing.