Earmuffs, exploratory head movements, and horizontal and vertical sound localization

Area of Science:

• Auditory perception
• Psychoacoustics
• Spatial hearing

Background:

• The human auditory system uses various cues for sound localization.
• The pinna plays a crucial role in vertical sound localization.
• Head movements can significantly influence sound localization accuracy.

Purpose of the Study:

• To investigate the effect of earmuffs and head movement on sound localization accuracy in both horizontal and vertical planes.
• To examine how auditory cues are utilized under different conditions.

Main Methods:

• Normal-hearing adults (N=17) localized narrow-band noise bursts from loudspeaker arrays in a semi-anechoic room.
• Conditions included free or restricted head movement, with and without earmuffs.
• Localization accuracy was measured in both horizontal and vertical planes.

Main Results:

• In the horizontal plane, accuracy decreased significantly with earmuffs (95% to 50%) and restricted head movement (95% to 24%).
• In the vertical plane, accuracy was substantially reduced by earmuffs (72% to 19%) even with free head movement.
• Free head movements did not fully compensate for the loss of pinna cues.

Conclusions:

• Listeners struggle to utilize available auditory cues when presented under altered bodily orientations, particularly with earmuffs.
• The findings suggest potential practical hazards related to impaired sound localization in certain real-world scenarios.
• Interaural cues may not be effectively recruited when generated under different head orientations.