Precedence

Question 1

(Litovsky et al., 1999).

Answer 1

The ‘‘precedence effect’’ refers to a group of phenomena that are thought to be involved in resolving competition for perception and localization between a direct sound and a reflection (Litovsky et al., 1999).

Question 2

Haas (1951)

Blauert (1997)

Answer 2

This effect has also been called the “Haas effect” after Haas (1951) and the “law of the first waveform” (Blauert, 1997).

Question 3

Wallach et al. (1949)

Answer 3

The term ‘‘precedence effect’’ was originally coined by Wallach et al. (1949) in their classic study to describe the dominance of the lead stimulus characteristics in the determination of the spatial location of the fused image localization dominance.

Question 4

(Zurek, 1980; Perrott et al., 1989)

Answer 4

The precedence effect is only shown for sounds of discontinuous or transient character and is reflected in the finding that the ability to detect shifts in the location of the lagging sound (the echo) is reduced for a short time following the onset of the leading sound (Zurek, 1980; Perrott et al., 1989).

Question 5

Blauert 1997

Answer 5

If the interval between the arrival of the two sounds is 1ms or less, the precedence effect does not operate; instead an average or compromise location is heard. This is called “summing localization” (Blauert, 1997).

Question 6

Brandewie and Zahorik (2010)

Answer 6

The precedence effect plays an important role in our perception of everyday sounds. It enables us to locate, interpret, and identify sounds in spite of wide variations in the acoustical conditions in which we hear them. Without it, listening and understanding speech in reverberant rooms would be an extremely confusing experience (e.g. Brandewie and Zahorik 2010).

Question 7

(Brown, Stecker, & Tollin, 2014)

Answer 7

Precedence effect-like phenomena have been reported in nearly every organism examined, from amphibians to canines to humans; the premises and interpretations of these many studies have often focused on the utility of precedence effect for echo suppression, that is, avoidance of the perceptual effects of echoes that might otherwise confound sound localization in real environments. This view, in turn, holds that the precedence effect facilitates (depending on the organism) communication, environmental awareness, prey capture, and/or predator avoidance in natural environments (Brown, Stecker, & Tollin, 2014).

Question 8

Zurek (1980)

Answer 8

Zurek (1980) suggested that the precedence effect is useful for the avoidance of inter-aural ambiguities.

Question 9

(Brown et al., 2015)

Answer 9

The biological basis of the precedence effect remains unclear, despite decades of study (Brown et al., 2015).

Question 10

Bianchi, Verhulst, and Dau (2013)

Answer 10

Bianchi, Verhulst, and Dau (2013) investigated the contribution of cochlear peripheral processing and found evidence of lag suppression occuring at the basilar membrane in the time range from 1 to 4 milliseconds evidenced by the suppression of lag click-evoked otoacoustic emissions.

Question 11

(Fitzpatrick et al. 1999; Litovsky et al. 1999)

Answer 11

Beyond the cochlea, extensive reviews of neurophysiological precedence effect literature have considered the temporal extent of precedence effect-like neural responses at multiple levels of the auditory system—from auditory nerve to cortex (Fitzpatrick et al. 1999; Litovsky et al. 1999). These reviews collectively implicate the inferior colliculus as the site at which strong suppression of the lag is first observed on a time course consistent with psychophysical observations.

Question 12

Xia et al. (2010)

Answer 12

Similarly, Xia et al. (2010) concluded that location-dependent suppression of in the inferior colliculus neurons can explain the precedence effect

Question 13

Brown et al. (2015)
(Bianchi et al., 2013)
Brown et al. (2015)

Answer 13

Brown et al. (2015) evaluated the precedence effect in bilateral cochlear implant users. The data suggest that aspects of the precedence effect can be elicited in cochlear implant users, who lack functional cochlea, thus suggesting that neural mechanisms are sufficient to produce the precedence effect. While cochlear-mechanics may still contribute to the precedence effect at low frequencies, data from Brown et al. (2015) suggest that the cochlea is not necessary for the precedence effect, at least over a range of higher frequencies

Question 14

(Cranford, Andres, Piatz, & Reissig, 1993; Cranford & Romereim, 1992)

Answer 14

Binaural temporal processing ability assessed by the precedence effect measured in the sound field declines with age (Cranford, Andres, Piatz, & Reissig, 1993; Cranford & Romereim, 1992).

Question 15

Abel et al. (2000)

Answer 15

Abel et al. (2000) observed a systematic decline in horizontal plane localization with increasing age, starting as early as age 30.

Question 16

(e.g., Cranford et al. 1993; Goverts et al. 2002; Roberts et al. 2002, 2003; Roberts and Lister 2004; Lister and Roberts 2005; Akeroyd and Guy 2011).

Answer 16

Likewise, a number of investigations over the past two decades have assessed the precedence effect in people with hearing loss (e.g., Cranford et al. 1993; Goverts et al. 2002; Roberts et al. 2002, 2003; Roberts and Lister 2004; Lister and Roberts 2005; Akeroyd and Guy 2011).

Question 17

(Roberts et al. 2002; Roberts and Lister 2004, 2004)

Cranford et al. 1993; Goverts et al. 2002; Akeroyd and Guy 2011

Answer 17

While data have been widely variable, hearing-impaired individuals clearly experience both fusion (e.g., Roberts et al. 2002; Roberts and Lister 2004, 2004) and localization dominance (Cranford et al. 1993; Goverts et al. 2002; Akeroyd and Guy 2011).

Question 18

(Cranford et al. 1993; Goverts et al. 2002)

Answer 18

However, the effect of localization dominance does appear to be weaker in hearing-impaired listeners than in normal-hearing individuals (Cranford et al. 1993; Goverts et al. 2002).

Question 19

Akeroyd and Guy (2011)

Answer 19

Research by Akeroyd and Guy (2011) demonstrated a significant correlation between localization dominance abilities and degree hearing loss, such that better hearing listeners demonstrated better localization dominance. One hypothesis for decreased performance of hearing-impaired subjects on binaural and spatial hearing tasks is that the binaural signal processing itself is less accurate in this population.

Question 20

Goverts, Houtgast, and van Beek (2001)

Answer 20

Goverts, Houtgast, and van Beek (2001) investigated the effect of mild symmetrical sensorineural hearing loss on the precedence effect. Using dichotic signals presented by headphone, stimulus onset dominance (the precedence effect for lateralization) was examined for six subjects. Data from subjects with mild sensorineural hearing loss show large amounts of variance and an overall decrease in the precedence effect, which cannot be explained on basis of reduced audibility.

Question 21

(Houtgast and Steeneken, 1973)

Answer 21

Reverberation, like noise, acts like a low-pass filter, in that it smooths the modulations in the stimulus envelope (Houtgast and Steeneken, 1973).

Question 22

(Helfer & Huntley, 1991).

Answer 22

However, reverberation is a more complex example of distortion because it not only causes masking (from reflected energy), but it also smears the temporal structure of the signal (Helfer & Huntley, 1991).

Question 23

(Helfer & Huntley, 1991)

Lutman et al., 1991; Price & Simon, 1984

Answer 23

In a study aimed to examine the influence of aging and hearing loss on consonant perception in reverberation and noise, at least some of the data suggest that hearing loss of varying degrees adversely affects older listener’s ability to identify distorted consonants (Helfer & Huntley, 1991); however, hearing loss was an inadequate explanation for all of the speech perception difficulties of older adults, consistent with other studies, suggesting that age-related deterioration in adverse listening environments may be independent of hearing status (Lutman et al., 1991; Price & Simon, 1984).

Question 24

Picou, Moore, and Ricketts (2017)

Answer 24

In a study aimed to evaluate the effects of hearing aid directional processing on subjective and objective listening effort, Picou, Moore, and Ricketts (2017) concluded that directional microphone technology in hearing aids has the potential to improve listening effort in moderately reverberant environments, but not in environments of low reverberation.

Question 25

Reinhart, Zahorik, and Souza (2017)

Answer 25

Similarly, Reinhart, Zahorik, and Souza (2017) varied the amount of degradation from reverberation to hearing aid input signals for hearing-impaired listeners completing a low-context sentence comprehension task and found that the benefit of digital noise reduction processing in hearing aids may depend on the amount of reverberation in the environment.

Question 26

Litovsky et al. 2006; Grantham et al. 2008

Answer 26

While cochlear implants can sometimes restore hearing through electrical stimulation, performance in “binaural” tasks, including sound localization, remains poor in most bilateral CI users (e.g., Litovsky et al. 2006; Grantham et al. 2008).

Question 27

(Brown, Stecker, & Tollin, 2014)

Answer 27

A certain constraint on performance is that the devices do not preserve temporal information carried by the input signal (e.g., most devices provide no temporal fine structure cues and are not synchronized across the ears), which particularly limits sensitivity to ITD (Brown, Stecker, & Tollin, 2014).

Question 28

(Kerber and Seeber 2013)

Answer 28

Poorer ITD sensitivity within individual subjects is associated with worse localization in reverberation (Kerber and Seeber 2013), suggesting in turn that the precedence effect, which strongly depends on ITD cues, may be abnormal in users of bilateral CIs.

Question 29

(Seeber and Hafter 2008)

Agrawal 2008

Answer 29

Both widely variable fusion echo thresholds (Seeber and Hafter 2008) and relatively weak localization dominance and lag suppression (Agrawal 2008) have been documented for cochlear implant users. In contrast, under direct stimulation, a procedure by which the binaural information provided by bilateral CIs can be precisely controlled via custom research processors, the precedence effect appears to be more intact.

Question 30

van Hoesel (2007) and Agrawal (2008)
(Agrawal 2008; Litovsky et al. 2010)

Answer 30

Data reported by van Hoesel (2007) and Agrawal (2008) suggested qualitatively similar discrimination suppression in bilateral CI and normal-hearing listeners, at least among bilateral CI users with adult-onset deafness (Agrawal 2008; Litovsky et al. 2010).