Notes⌗

Kolarik, Andrew J., J. Moore, Brian C., Zahorik, Pavel, Cirstea, Silvia, and Shahina Pardhan. “Auditory distance perception in humans: a review of cues, development, neuronal bases, and effects of sensory loss.” Attention, Perception & Psychophysics 78, (2015): 373-395. Accessed August 29, 2023. https://doi.org/10.3758/s13414-015-1015-1.

Introduction⌗

There are four aspects of auditory distance perception:

1. cue processing,
2. development,
3. consequences of visual and auditory loss, and
4. neurological bases

The primary cues are:

1. sound level,
2. reverberation, and
3. frequency

The importance of the sound to the listener can also affect the perceived distance.

• Distance categories:
  • Peripersonal space - sounds that are within reaching and grasping distance (approximately 1 m from the listener)
  • Extrapersonal space - farther sounds
  • “some cues are only useful within peripersonal space”

Perceiving distance using sound⌗

On average, perceived distance to sound sources in peripersonal space tends to be overestimated, while distance to sounds in extrapersonal space is generally underestimated for normally sighted and hearing humans

Level⌗

• relative distance cue that is available in most environments
• effective over a wide range of distances.
• Perceived source distance generally increases with decreasing level of the sound at the ears of the listener (receiver)

Level is a relative distance cue, as distance judgments made solely on the basis of level may be confounded by variation in the level at the source (Zahorik et al., 2005).

Direct-to-reverberant energy ratio (DRR)⌗

he presence of reverberation for distance judgments is beneficial, as DRR is an important cue for judging sound-source distance (Bronkhorst & Houtgast, 1999; Kopčo & Shinn-Cunningham, 2011; Mershon, et al., 1989; Mershon & King, 1975; von Békésy, 1938; Zahorik, 2002a, 2002b).

The DRR decreases as source distance from the listener increases, and this is associated with increasing perceived distance. Direct sound energy travels in a straight line from the source to the listener, and, for an omni-directional source, its level falls by 6 dB for each doubling of the source distance. Reverberant sound energy is reflected from surfaces, such as walls or objects, before reaching the listener and can be approximated by a diffuse sound field with constant energy regardless of source location if the room is not too small; the level of the reverberant sound varies only slightly with distance (Zahorik, 2002a).

Spectral Cues⌗

Spectral shape can be used to perceive the distance to sound sources more than 15 m from the listener (Blauert, 1997) and also to sounds in peripersonal space (Brungart, 1999; Kopčo & Shinn-Cunningham, 2011). For far away sources, as sound travels through air higher frequencies become more attenuated than lower frequencies, altering the spectral shape. Sounds with decreased high-frequency content relative to low-frequency content are perceived to be farther away (Butler, Levy, & Neff, 1980; Coleman, 1968; Little, Mershon, & Cox, 1992; von Békésy, 1938).

Spectral content also is important in perceiving distance to nearby sounds, due to the way that diffraction of sound around the head varies with frequency and distance.

Note that spectral cues do not provide distance information for sounds located in the range 1-15 m from the listener, for which the sound has not traveled far enough to have lost a detectable amount of energy at higher frequencies and the low-frequency cues provided by diffraction around the head are too small to be detected.

Table⌗

Table 1

Stimulus familiarity⌗

Experience with sound sources previously heard across a range of distances can increase the accuracy of perceived distance judgments, because listeners can compare spectral content and sound level at the ears with an internal estimate of the probable spectra and output power of the sound source. For example, a siren from a fire engine with a low level at the receiver’s ears is normally perceived to be far away, because sirens generally have a high output power (Philbeck & Mershon, 2002). Stimulus familiarity is particularly useful for stimuli that are consistent in overall level and spectral content, such as gunshots (Zahorik, et al., 2005).