Which cues are primarily used to localize a sound with energy centered at 700 Hz in a normally hearing person?

Which cues are primarily used to localize a sound with energy centered at 700 Hz in a normally hearing person?

• A. Interaural time and intensity differences
• B. Interaural time differences only
• C. Spectral cues and interaural intensity differences
• D. Interaural intensity differences only

Answer: (B)

At 700 Hz, timing differences between the ears are the main clue the brain uses to judge where a sound comes from. This frequency is low enough that the auditory system can phase-lock to the waveform, so the brain can detect small differences in when the wave arrives at each ear. The time difference, or interaural time difference, reliably maps to sound azimuth in the horizontal plane, making it the primary cue for localization at this frequency. Interaural level differences become more influential at higher frequencies where the head creates a noticeable shadow and causes louder sound on one side. At 700 Hz, these level differences are relatively small, so they aren’t the dominant cue. Spectral cues from the outer ear help with vertical localization and distinguishing front from back, but they’re not the main factor for a sound centered at this frequency in the horizontal plane. Thus, interaural time differences are the best cue for localizing a 700 Hz sound in a normally hearing person.

At 700 Hz, timing differences between the ears are the main clue the brain uses to judge where a sound comes from. This frequency is low enough that the auditory system can phase-lock to the waveform, so the brain can detect small differences in when the wave arrives at each ear. The time difference, or interaural time difference, reliably maps to sound azimuth in the horizontal plane, making it the primary cue for localization at this frequency.

Interaural level differences become more influential at higher frequencies where the head creates a noticeable shadow and causes louder sound on one side. At 700 Hz, these level differences are relatively small, so they aren’t the dominant cue. Spectral cues from the outer ear help with vertical localization and distinguishing front from back, but they’re not the main factor for a sound centered at this frequency in the horizontal plane.

Thus, interaural time differences are the best cue for localizing a 700 Hz sound in a normally hearing person.