Content uploaded by John Neuhoff
Author content
All content in this area was uploaded by John Neuhoff on Nov 23, 2016
Content may be subject to copyright.
O R I G I N A L A R T I C L E Open Access
Looming sounds are perceived as faster
than receding sounds
John G. Neuhoff
Abstract
Each year thousands of people are killed by looming motor vehicles. Throughout our evolutionary history looming
objects have posed a threat to survival and perceptual systems have evolved unique solutions to confront these
environmental challenges. Vision provides an accurate representation of time-to-contact with a looming object and
usually allows us to interact successfully with the object if required. However, audition functions as a warning
system and yields an anticipatory representation of arrival time, indicating that the object has arrived when it is still
some distance away. The bias provides a temporal margin of safety that allows more time to initiate defensive
actions. In two studies this bias was shown to influence the perception of the speed of looming and receding
sound sources. Listeners heard looming and receding sound sources and judged how fast they were moving.
Listeners perceived the speed of looming sounds as faster than that of equivalent receding sounds. Listeners also
showed better discrimination of the speed of looming sounds than receding sounds. Finally, close sounds were
perceived as faster than distant sounds. The results suggest a prioritization of the perception of the speed of
looming and receding sounds that mirrors the level of threat posed by moving objects in the environment.
Keywords: Auditory looming, Auditory motion perception, Adaptation
Significance
Moving motor vehicles injure and kill hundreds of thou-
sands of pedestrians each year. This situation has the po-
tential to get dramatically worse as both the production
of quieter electric and hybrid vehicles and the number
of pedestrians distracted by hand-held electronic devices
increase. However, a better understanding of the percep-
tual and cognitive aspects of looming sounds could lead
to a reduction in these fatalities. These two experiments
show that auditory perception of the speed of sounding
objects in motion is related to their direction of travel
and their distance from the listener. Sound sources that
pose the greatest risk, those that are close and those that
approach, are perceived to move faster than those that
are distant or moving away. This perceptual bias sug-
gests an evolutionary influence on our perception of
looming auditory motion.
Background
In the five-year period from 2009 to 2013, over
20,000 pedestrians were killed in the United States by
moving motor vehicles (National Highway Traffic Safety
Administration, 2015). Throughout our evolutionary
history, looming objects have been a similar source of po-
tential danger and perceptual systems have evolved in ad-
vantageous (though not perfect) ways to deal with such
threats. The visual system provides a relatively accurate
and precise estimate of arrival time that allows us to inter-
act with looming objects effectively (McBeath, Shaffer, &
Kaiser, 1995; Regan & Vincent, 1995). However, our field
of vision is limited and of little value under poor viewing
conditions (e.g. night-time) or when approaching objects
are occluded. Audition is particularly useful under these
conditions and typically functions as a warning system
that gives an added measure of safety in dealing with
looming objects (Guski, 1992; Rosenblum, Carello, &
Pastore, 1987; Rosenblum, Wuestefeld, & Saldana, 1993).
Looming sounds initiate a series of protective physio-
logical, cognitive, emotional, and behavioral responses
that do not occur in response to sounding objects
that move in any other direction. Compared to
equivalent receding sounds, looming sounds preferen-
tially activate the amygdala and a distributed neural
network that supports attention, auditory space and
motion perception, and motor planning—all responses
indicative of an adaptive trait that has evolved to keep
Correspondence: jneuhoff@wooster.edu
Department of Psychology, The College of Wooster, Wooster, OH 44691, USA
C
ognitive Researc
h
: Princip
l
es
and Im
p
lications
© 2016 The Author(s). Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0
International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and
reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to
the Creative Commons license, and indicate if changes were made.
Neuhoff Cognitive Research: Principles and Implications (2016) 1:15
DOI 10.1186/s41235-016-0017-4
organisms safe (Bach et al., 2008; Bach, Furl, Barnes, &
Dolan, 2015; Bach, Neuhoff, Perrig, & Seifritz, 2009; Sei-
fritz et al., 2002).
When listeners are asked to predict the arrival time of
a looming sound, they exhibit a systematic anticipatory
error and perceive that the source has arrived when it is
still some distance away
1
(Neuhoff, Hamilton, Gittleson,
& Mejia, 2014; Neuhoff, Long, & Worthington, 2012;
Neuhoff, Planisek, & Seifritz, 2009; Riskind, Kleiman,
Seifritz, & Neuhoff, 2014; Rosenblum et al., 1987, 1993;
Schiff & Oldak, 1990). This bias can provide a selective
advantage by creating a temporal “margin of safety”that
affords slightly more time than expected to initiate de-
fensive behaviors in response to the looming object
(Freiberg, Tually, & Crassini, 2001; Glatz, Bulthoff, &
Chuang, 2014; Neuhoff, 1998, 1999, 2001). Studies on
sex differences have shown that women tend to exhibit a
larger looming bias than men (Grassi, 2010; Schiff &
Oldak, 1990) and these findings are likely due to sex dif-
ferences in the ability to deal with approaching threat
(e.g. physical strength) rather than any differences in
auditory spatial localization. For example, Neuhoff et al.
(2009) showed that women perceive looming sounds as
closer than men do. However, there was no difference
between men and women in the perception of sounds
that traveled away from the listener. Moreover, the mag-
nitude of the looming bias is negatively correlated with
physical strength and cardiac fitness (Neuhoff et al.,
2012), consistent with the interpretation that the ability
to deal effectively with a looming threat contributes to
the magnitude of the bias. Individuals least prepared
physically to deal with the oncoming threat have the lar-
gest perceptual margin of safety. Additional converging
evidence for the adaptive looming bias hypothesis comes
from comparative work on rhesus monkeys who show
a pattern of response to looming versus receding
sounds that mirrors that found in humans (Ghazanfar,
Neuhoff, & Logothetis, 2002; Maier, Chandrasekaran,
& Ghazanfar, 2008; Maier & Ghazanfar, 2007; Maier,
Neuhoff, Logothetis, & Ghazanfar, 2004).
The auditory looming bias is part of a family of cogni-
tive and perceptual biases that fall under the umbrella of
“Error Management Theory”(Haselton et al., 2009;
Haselton & Buss, 2000; Haselton & Nettle, 2006). Error
Management Theory proposes that cognitive biases will
evolve when judgments are made under conditions of
uncertainty, when the decisions have historically had an
impact on evolutionary fitness, and when there is an
asymmetric cost of making false-positive and false-
negative errors. There is a degree of uncertainty in any
perceptual judgment and errors in judging auditory ar-
rival time can clearly impact evolutionary fitness. The
false-positive of responding too early is far less costly
than the false-negative of responding too late.
From a psychophysical perspective, previous work has
debated whether auditory motion is perceived directly or
simply inferred from changes in distance by using “snap-
shots”at successive locations, with the bulk of the evi-
dence suggesting that the auditory system can do both
depending on the conditions (Carlile & Leung, 2016;
Grantham, 1997). Egocentric auditory distance perception
has already been shown to be a contributing factor in the
auditory looming bias. For example, when listeners are
asked to make stationary distance judgments of looming
and receding sounds that have come to stop at the same
egocentric distance from the listener, looming sounds are
perceived as closer than receding sounds (Neuhoff, 2001;
Neuhoff et al., 2009). However, there may also be a bias in
speed perception. Differential estimates of speed for loom-
ing versus receding sounds could provide additional sup-
port for Error Management Theory and be consistent
with an evolutionary perspective on the role of adaptive
processes in auditory perception.
From a neurophysiological perspective, auditory recep-
tive fields have been shown to be dynamic in nature and
shift toward the motion of the sound, with the magnitude
of these receptive field shifts increasing as the speed of the
sound source increases (Witten, Bergan, & Knudsen,
2006). Although this work examined sounds that moved
in azimuth (around the head), there may be similar mech-
anisms at work in processing looming sounds. Studies
with humans and other animals have identified neural cor-
relates of looming sounds and have implicated both cor-
tical and subcortical regions that respond preferentially to
looming sounds (Bach et al., 2008, 2009; Cappe, Thelen,
Romei, Thut, & Murray, 2012; Ghazanfar et al., 2002;
Maier & Ghazanfar, 2007; Seifritz et al., 2002). Similar
work with auditory motion in azimuth has shown that a
sounding object that enters an auditory receptive field
produces more robust responding than one leaving it
(Ingham, Hart, & McAlpine, 2001; Wilson & O’Neill,
1998). Thus the differential effects of increasing stimulus
speed could be enhanced for looming sounds over reced-
ing much like looming and receding sounds of the same
speed produce differential neural responses.
If the looming bias is an adaptive trait that has evolved
as a protection mechanism against approaching danger,
then we might expect listeners to perceive the speed of
looming sounds as faster than that of equivalent reced-
ing sounds. We might also expect listeners to show bet-
ter discrimination for the speed of looming sounds than
for the speed of receding sounds because approaching
sounds are more salient. Finally, we might expect lis-
teners to perceive close sounds as faster than distant
sounds because of their greater potential for danger. In
two experiments we tested these hypotheses by present-
ing listeners with looming and receding sound sources
and asking them to judge how fast they were moving.
Neuhoff Cognitive Research: Principles and Implications (2016) 1:15 Page 2 of 9
Experiment 1
Method
Participants
The sample for Experiment 1 consisted of 80 partici-
pants (26 women) with an average age of 33.5 years
(SD 9.9). Sample size was determined by examining
prior auditory looming studies that used terminal dis-
tance as the dependent variable (rather than the
speed estimates used here). These studies have typic-
ally used sample sizes of around 40 (e.g. Neuhoff
et al., 2009). However, this sample size was doubled
because of greater potential variability in the current
experiment due to the online nature of the data col-
lection (participants listened to the stimuli and
responded on their own equipment). Data were col-
lected until the target sample of 80 was reached. All
participants reported normal hearing. All were re-
cruited via Amazon Mechanical Turk (MTurk) and
were paid $0.30 to complete the experiment online. A
wide variety of research shows that samples from
MTurk have reliability that is as good as or better
than that obtained from traditional undergraduate
samples (Buhrmester, Kwang, & Gosling, 2011;
Holden, Dennie, & Hicks, 2013; Paolacci, Chandler, &
Ipeirotis, 2010). Moreover, traditional attention and
psychophysical tasks have been well replicated on
MTurk including experiments on the Stroop effect,
flanker task, Simon effect, Attentional Blink, task
switching, inhibition of return, and masked priming
(Crump,McDonnell,&Gureckis,2013).Threepartic-
ipants were eliminated from the analysis of Experi-
ment 1 because they misunderstood the task and gave
estimates of the “speed of sound”that were all more
than 600 mph. The study was approved by the Insti-
tutional Review Board of The College of Wooster and
all participants provided informed consent.
Stimuli
Stimuli consisted of a moving three-dimensional (3D)
virtual sound source presented over headphones that
traveled on a path parallel to the interaural axis of
the listener. The virtual listening point was situated 2
m from the straight-line trajectory of the source (see
Fig. 1). “Distant”stimuli approached and receded
along a path between 60 m and 15 m from the me-
dian plane of the listener. “Close”stimuli approached
and receded along a path between 2 m and 47 m
from the median plane of the listener. Stimuli trav-
eled at 15 mps (33.5 mph), 20 mps (44.7 mph), and
25 mps (55.9 mph). The sound source was a square
wave with a fundamental frequency of 400 Hz and a
sampling rate of 44.1 kHz. The virtual source height
was 0.5 m. The simulation produced realistic 3D
auditory motion that included Doppler shift, atmos-
pheric filtering, gain attenuation due to atmospheric
spreading, ground reflection attenuation, and head-
related transfer function (HRTF) from the MIT
KEMAR dataset (Gardner & Martin, 1995; see
Neuhoff et al., 2009 for simulation details). We used
a bypass trajectory to maximize interaural cues to
the source’s approach. Stimuli are available at
http://www.jneuhoff.com/links.html.
Design and procedure
After providing informed consent, participants were
asked by a recorded voice to adjust their volume to a
comfortable listening level. As verification that they
could hear the stimuli, they were asked to enter a code
word into a blank text box, then to indicate the model
headphones that they were using. They then chose the
unit of speed that they were most familiar with (mph or
km/h) to make speed estimates. All estimates in were
later transformed to mps for analysis. Participants were
instructed to listen to the audio clip and then estimate
to the best of their ability how fast the sound source was
traveling. Each participant heard two sounds in each
condition (2 Distance × 2 Direction × 3 Speed) for a total
of 24 trials. One sound in each condition approached/re-
ceded from the left. The other approached/receded from
the right. The two responses in each condition were av-
eraged to yield a single speed estimate for each condi-
tion. After hearing each sound, participants typed their
Close motion path 2-47 m Distant motion path 15-60 m
2 m 15 m 47 m 60 m
2 m
Virtual
listening
point
Fig. 1 Stimulus configuration for Experiments 1 and 2. A virtual sound source approached or receded along a path parallel to the listener’s
interaural axis at three different speeds. The listener was situated 2 m from the straight-line path of the source facing perpendicular to the path.
In the “Close”condition, the sound source traveled between 2 m and 47 m from the median plane of the listener. In the “Distant”condition, the
source traveled between 15 m and 60 m from the median plane of the listener
Neuhoff Cognitive Research: Principles and Implications (2016) 1:15 Page 3 of 9
speed estimate into a blank text box and clicked an
arrow on the screen to advance to the next sound. Previ-
ous work has used a similar labeling method for asses-
sing perceived speed (Recarte, Conchillo, & Nunes,
2000; Recarte & Nunes, 1996; Triggs & Berenyi, 1982).
Results and discussion
Participants generally underestimated actual speed (except
in the slowest condition). However, this is a typical finding
when participants are asked to verbally estimate speed
(Recarte & Nunes, 1996; Triggs & Berenyi, 1982). Thus, our
analysis is concerned only with relative differences between
conditions, as accuracy in verbally applying metric values to
perceptual stimuli typically shows much poorer performance
than a motor response (Andre & Rogers, 2006), particularly
with looming sounds (Neuhoff, 2001). A 2 (Direction) × 2
(Distance) × 3 (Speed) Repeated-Measures Analysis of Vari-
ance (ANOVA) revealed a main effect for Direction indicat-
ing that looming sounds (M = 39.1, SE = 2.3) were perceived
as moving significantly faster than receding sounds
(M = 32.2, SE = 2.3), F (1,76) = 17.8, p<0.001, η
p
2
= 0.19.
There was also a much larger main effect for Distance indi-
cating that close sounds (M = 40.6, SE = 2.3) were perceived
as moving faster than distant sounds (M = 30.8, SE = 2.1), F
(1,76) = 76.6, p< 0.001, η
p
2
= 0.50, and a smaller main effect
for Speed (see Table 1), F (1.83,76) = 5.9, p= 0.005, η
p
2
=0.07
(Greenhouse-Geisser correction used to correct for spher-
icity violation). However, this effect was moderated by a sig-
nificant interaction between Direction and Speed, F (2,152)
=4.6, p= 0.01, η
p
2
= 0.06. Scores were collapsed across Dis-
tance to examine this interaction and separate ANOVAs
were performed on the Looming and Receding trials with
Speed as the only independent variable. The analysis
revealed a main effect of Speed for looming sounds F (2,68)
=3.1, p= 0.05, η
p
2
= 0.08, indicating that listeners could dis-
criminate among the different speeds of looming sounds
(See Fig. 2a). Post-hoc Tukey tests revealed significant differ-
ences in perceived speed between the 25 mps and 15 mps
conditions and between the 20 mps and 15 mps conditions,
p< 0.05. Importantly, there was no significant difference
among the perceived speeds of receding sounds, F (2,68) =
0.81, p= 0.49, η
p
2
= 0.02. Finally, there was a significant
interaction of Distance and Direction, F (1,76) = 13.3,
p< 0.001, η
p
2
= 0.15. Follow-up analyses showed a significant
difference in perceived speed between close looming sounds
(M = 45.9, SD = 24.1) and close receding sounds (M = 35.2,
SD = 21.6), t(76) = 4.7, p< 0.001. There was also a significant
difference between distant looming sounds (M = 32.4,
SD = 18.6) and distant receding sounds (M = 29.3,
SD = 22.3), t(76) = 2.0, p= 0.04. However, the effect
size for the difference between close looming and receding
sounds (d = 0.47) was over three times the effect size for
the difference between distant looming and receding
sounds (d = 0.15), indicating a perceptual priority for
speed discrimination among sounds that are close. The
three-way interaction of Direction × Distance × Speed was
not significant F (2,152) = 1.28, p=0.30,η
p
2
=0.03.
Looming sounds and close sounds were both perceived
to move faster than equivalent receding and distant
sounds. These results indicate a perceptual priority for
sounds most critical to the listener. In a natural environ-
ment sounds that are close and sounds that are ap-
proaching have the potential to pose the greatest danger.
The interaction between Speed and Direction supports
this position by showing that listeners have greater sen-
sitivity to the speed of auditory motion when a sound
source is approaching than when it is receding. The sig-
nificant interaction between Distance and Direction is
also consistent with the proposal.
Experiment 2
Experiment 1 showed that looming sounds and close
sounds are perceived to move faster than equivalent
receding and distant sounds and that listeners show
preferential perceptual processing for sounds that
have the most potential for danger. However, it is
possible that the within-subjects nature of the ex-
perimental design tipped participants off to the hy-
pothesis and created demand characteristics for our
evolutionary hypotheses about direction and dis-
tance. In Experiment 2, we used the same stimuli
and procedure but made Distance and Direction
between-subjects factors. Thus, each participant pro-
vided speed estimates for only three sounds (at 15
mps, 20 mps, 25 mps) in one of the four conditions
(close-looming, close-receding, distant looming, or
distant-receding). This design eliminated any poten-
tial demand characteristics on our primary variables
of interest.
Method
Participants
The sample for Experiment 2 consisted of 200 partici-
pants (77 women) with an average age of 32.1 years (SD
10.1). Sample size was determined by examining prior
auditory looming studies that used between-subjects
Table 1 Mean estimates of perceived speed by condition in
Experiments 1 and 2
Experiment 1 Experiment 2
M (SE) M (SE)
15 mps 15.1 (2.4) 13.5(0.94)
20 mps 16.1 (1.0) 14.4(0.98)
25 mps 16.7 (0.9) 14.9(0.98)
Notes: The small significant main effects for speed in each experiment were
moderated by significant interactions. Participants made speed estimates in
either mph or km/h. All estimates were transformed to mps for analysis. 15
mps = 33.6 mph, 20 mps = 44.7 mph, 25 mps = 55.9 mph.
Neuhoff Cognitive Research: Principles and Implications (2016) 1:15 Page 4 of 9
variables. These studies have typically used sample sizes
of around 30 per condition (Neuhoff et al., 2014, 2009).
However, this sample size was increased because of
greater expected variability in the current experiment
due to the online nature of the data collection. Data
were collected until the target sample of 50 per each of
the four conditions was reached. All participants re-
ported normal hearing. All were recruited via MTurk
and were paid $0.30 to complete the experiment online.
Eleven participants were replaced because they misun-
derstood the task and gave estimates of the “speed of
sound”that were over 600 mph. The study was approved
by the Institutional Review Board of The College of
Wooster and all participants provided informed consent.
Stimuli
The stimuli were the same as those used in Experiment 1.
Design and procedure
The procedure was the same as that used in Experiment
1. However, in the between-subjects design of Experi-
ment 2, each participant heard three sounds (one at each
velocity) in only one of the four (2 Distance × 2 Direc-
tion) conditions for a total of three trials. Half the partic-
ipants heard the sounds approach/recede from the left.
The other half heard sounds approach/recede from the
right.
Results and discussion
A 2 × 2 × 3 Mixed-Design ANOVA was conducted on
the speed estimates with the between-subjects factors
“Direction”(looming/receding) and “Distance”(2 m, 15
m) and the within-subjects factor “Speed”(15 mps, 20
mps, 25 mps). Looming sounds (M = 36.3, SE = 2.9) were
again perceived as significantly faster than receding
sounds (M = 27.6, SE = 2.9), F(1, 196) = 4.4, p< 0.037, η
p
2
= 0.02. Close sounds (M = 36.9, SE = 2.9) were again
perceived as faster than distant sounds (M = 27.0, SE =
2.9), F(1, 196) = 5.7, p= 0.018, η
p
2
= 0.03. There was also a
significant effect for Speed (see Table 1), F(1.9, 392) =
3.2, p= 0.045, η
p
2
= 0.02 (Greenhouse-Geisser correction
used to correct for sphericity violation). The main effect
for Speed was once again moderated by a significant
Speed × Direction interaction, F(2, 392) = 9.1, p< 0.001,
η
p
2
= 0.05. Separate follow-up ANOVAs for Looming and
Receding conditions with Speed as the within-subjects
variable indicated a main effect for Speed of looming
sounds, F(2, 198) = 18.2, p< 0.001, η
p
2
= 0.16, indicating
that listeners could discriminate among the different
speeds of looming sounds (See Fig. 2b). Post-hoc Tukey
tests showed significant differences between all three
speed conditions for looming sounds, p< 0.05. However,
there was no significant difference in the speed estimates
of receding sounds F(2, 198) = 0.07, p= 0.93, η
p
2
< 0.001
The interactions between Distance × Direction F(2, 198)
= 0.05, p= 0.82, η
p
2
< 0.01, Speed × Distance F(2, 392) =
0.07, p= 0.82, η
p
2
< 0.01, and the three-way interaction of
Direction × Distance × Speed F(2, 198) = 0.05, p= 0.82,
η
p
2
< 0.01 were not significant.
The results of Experiment 2 replicate the main find-
ings of Experiment 1. Listeners treat looming sounds
and close sounds with perceptual priority. They perceive
them as moving faster than receding and distant sounds
of equal speed. Listeners also have greater speed dis-
crimination for looming sounds than for receding
sounds even when they only hear sounds that travel in
one direction.
General discussion
The current results show that the auditory system priori-
tizes the perceptual processing of looming sounds in a
way that mirrors their potential for danger based on
their proximity to the listener and their direction of
travel. Close looming sounds pose the greatest potential
0
5
10
15
20
25
Approach Recede
Direction of Travel
25 mps 20 mps 15 mps
0
5
10
15
20
25
Approach Recede
Estiamted speed (mps)
Estiamted speed (mps)
Direction of Travel
25 mps 20 mps 15 mps b
*
**
*
a
*
*
Fig. 2 Mean speed estimates for each speed and direction condition collapsed across the two distances. The interaction of stimulus speed and direction
of travel was significant in (a) Experiment 1, within-subjects design (n = 77) and (b) between-subjects design (n = 200). In both studies listeners show
significant speed discrimination for looming sounds but no difference in the perceived speed of receding sounds. Error bars represent 95 % confidence
intervals. * p< 0.01, ** p<0.05
Neuhoff Cognitive Research: Principles and Implications (2016) 1:15 Page 5 of 9
threat and are perceived as moving faster than equiva-
lent receding sounds. Listeners also show greater speed
discrimination for looming sounds than they do for re-
ceding sounds. These findings are consistent with the in-
terpretation that the perception of auditory motion has
been shaped in part by the environmental challenges
posed by our ancestors and that the auditory looming
bias adaptation is specific to the conditions that pose the
greatest potential for danger.
The results also show a bias in speed perception of
looming sounds that occurs in the absence of distance-
related tasks. Although listeners may sometimes use
changes in distance to estimate speed, there is also good
evidence for the direct detection of auditory speed
(Carlile & Best, 2002; Freeman et al., 2014; Locke,
Leung, & Carlile, 2016; Warren, Zielinski, Green,
Rauschecker, & Griffiths, 2002). It is notable that speed
estimates in all but the slowest stimulus condition were
generally less than the actual speed of the stimuli. Re-
cent psychophysical work has also shown an underesti-
mation of auditory speed in a circular pattern around
the head (Senna, Parise, & Ernst, 2015). However, the
current finding is likely the result of a well-documented
difficulty in applying metric labels accurately to speed
stimuli rather than a true perceptual underestimation of
the speed of approach (Recarte et al., 2000; Recarte &
Nunes, 1996; Triggs & Berenyi, 1982). For example, pre-
vious research using the same stimuli required partici-
pants to execute a button push when a looming sound
source arrived and participants significantly underesti-
mated arrival time indicating a perceived speed that was
faster than actual (Neuhoff et al., 2014, 2012; Riskind
et al., 2014). Because “labeling”the speed of looming
sounds is typically not a priority in a natural environ-
ment, the primary concern here was to examine relative
differences between conditions rather than absolute esti-
mates of speed. Moreover, participants show better ac-
curacy with a motor response than a verbal response in
judging looming stimuli (Neuhoff, 2001).
The auditory looming bias is technically a systematic
error in our perception of looming sounds. However,
Error Management Theory proposes that a wide range
of social, cognitive, and perceptual biases have evolved
because they increase the likelihood of survival and
reproduction (Haselton et al., 2009; Haselton & Buss,
2000; Haselton & Nettle, 2006). Perceptual “errors”can
provide a selective advantage if they offer survival bene-
fits that exceed those obtained from veridical perception.
The differential benefit of the looming bias is demon-
strated if we contrast a listener with veridical perception
to a listener with a bias to hear looming sounds as closer
than they are. On average, the listener with veridical per-
ception perfectly predicts the arrival time of the source
and the listener with the looming bias responds
consistently early. However, each listener has also a de-
gree of variability associated with their arrival time judg-
ments, each sometimes responding slightly earlier or
slightly later than their respective means. Early judg-
ments that provide more time than expected to prepare
for the arrival of the source are not problematic for ei-
ther listener. However, a listener with veridical percep-
tion who responds just a half second late is responding
after the source has already arrived, whereas late re-
sponse by the listener with the looming bias may still
leave enough time to respond safely.
It is likely that the looming bias is an automatic
process not under conscious control. Several studies
have shown increased autonomic nervous system re-
sponses to looming sounds consistent with a protective
mechanism (Bach et al., 2009; Fletcher et al., 2015;
Tajadura-Jimenez, Valjamae, Asutay, & Vastfjall, 2010). If
the decision to engage the motor system in the face of a
looming sound source was entirely under conscious con-
trol, then anyone engaged with a high cognitive load at
the time would be disadvantaged in that there would be
fewer cognitive resources to devote to the approaching
danger. However, a recent study that manipulated cogni-
tive load while participants judged the arrival of a loom-
ing sound found just the opposite. McGuire, Gillath, and
Vitevitch (2016) asked listeners to judge when a looming
sound would reach them while under high cognitive load
(memorizing a seven-digit number) or low cognitive load
(memorizing a two-digit number). They found that the
looming bias was significantly larger under high cogni-
tive load. The finding that listeners respond sooner ra-
ther than later under high cognitive load suggests that
the bias to hear sounds as closer than actual is an auto-
matic process that requires little effortful cognitive pro-
cessing. However, conscious attention can in some cases
influence time-to-arrival estimates as some studies have
shown that repeated trials with feedback can reduce (but
not eliminate) the auditory looming bias (Rosenblum,
Gordon, & Wuestefeld, 2000).
The bias to hear looming sounds as closer and faster
than equivalent receding sounds is not well predicted by
any traditional psychophysical laws. Some of the bias as
tested in loudness change experiments may be due to an
“endpoint bias”(Canevet, Teghtsoonian, & Teghtsoonian,
2003; Teghtsoonian, Teghtsoonian, & Canevet, 2005),
where the end loudness of a rising intensity sound that
changes from 60 to 75 dB has a greater influence on loud-
ness change estimates than the end loudness of a falling
intensity sound that changes from 75 to 60 dB. The argu-
ment is that with equal endpoints in loudness the bias
might disappear. However, when listeners are asked
to make terminal distance estimates of real looming
and receding sounds in a real or virtual environ-
ments, looming sounds are perceived as significantly
Neuhoff Cognitive Research: Principles and Implications (2016) 1:15 Page 6 of 9
closer despite the same distance (or endpoint) from
the listener (Neuhoff, 2001; Neuhoff et al., 2009).
Thus, with real looming sounds, the endpoint bias
disappears. More importantly, any “psychophysical
explanation”for the effect would not imply that the
looming bias is not an evolutionary adaptation. Psy-
chophysics does not preclude evolution and if there
were a good psychophysical description of the effect,
it is highly likely that the causal direction would go
from the evolved adaptation to the psychophysical result
(Cauchoix & Chaine, 2016; Croston, Branch, Kozlovsky,
Dukas, & Pravosudov, 2015; Warren, 1981).
Conclusions
The current results show that moving sounds are per-
ceived as traveling fastest when they are in a position to
pose the greatest threat. They provide evidence for an
evolved perceptual auditory looming bias. Further sup-
port for the auditory looming bias as an adaptation
comes from several converging lines of research. Neuro-
imaging studies have identified specific neural mecha-
nisms that preferentially process looming sounds over
auditory motion in other directions (Bach et al., 2008,
2009, 2015; Seifritz et al., 2002). Sex differences and a
correlation between physical fitness and the looming
bias suggest that the bias is related to the ability to de-
fend oneself in the face of a looming threat (Grassi,
2010; Neuhoff et al., 2009, 2012, 2014; Schiff & Oldak,
1990). Behavioral experiments show that listeners con-
sistently err on the side of safety when perceiving audi-
tory arrival time (Gordon & Rosenblum, 2005; Neuhoff,
2001; Rosenblum et al., 1987, 1993, 2000). Developmen-
tal work shows that the bias is present at a very early
age (Freiberg et al., 2001; Morrongiello, Hewitt, &
Gotowiec, 1991) and comparative research shows that
the bias occurs in a species closely related to humans
(Ghazanfar et al., 2002; Ghazanfar & Maier, 2009; Maier
et al., 2004; Maier & Ghazanfar, 2007). Together these
results provide strong support for an evolved bias in the
perception of looming sounds.
Though our everyday environment has been dramatic-
ally and rapidly changed by industry and technology.
Many of the evolved cognitive and perceptual adapta-
tions that we inherited from our ancestors remain. A
greater understanding of these evolutionary adaptations
can facilitate solving some of our modern day problems.
Endnotes
1
There is some evidence that suggests that visual time-
to-arrival is also underestimated, though not nearly as
much as in audition (e.g. Schiff & Oldak 1990). However,
this work employs a methodology that occludes that last
portion of approach of the looming object. Thus, the
task is really a prediction of the arrival time of an unseen
object based on a previously seen trajectory. Under
unoccluded conditions, humans show very high accuracy
in judging visual arrival time and a systematic anticipa-
tory bias in judging auditory arrival time. When a loom-
ing object (auditory or visual) suddenly disappears on
approach, there is simply no stimulus to perceive. Thus,
the task changes from one of “perception”to one of pre-
dictive “decision making.”It is likely that when one can
no longer hear nor see a previously looming object,
there is a common tendency to make conservative judg-
ments in both modalities. However, this process is not
“perception”per se. Nonetheless, there are some visual
studies that find asymmetries in favor of looming visual
motion. For example, observers have longer motion af-
tereffects for looming versus receding visual stimuli and
perceive ambiguous egocentric motion more often as
looming than receding (“Lewis and McBeath, 2004”;
Scott, Lavender, McWhirt, & Powell, 1966). On the
other hand, some work has shown a bias toward reced-
ing visual motion (Edwards & Ibbotson, 2007; Mueller &
Timney, 2014). As such, it is still an open question as to
whether the perception of looming objects represents
“amodal perception”across the auditory and visual mo-
dalities (Gordon & Rosenblum 2005; Rosenblum 2008)
Acknowledgments
Thanks to Christian Golden, Mark Hager, Jalen Lee, and Bryan Smith for
discussion and help with pilot data for this project.
Competing interests
The author declares that he has no competing interests.
Received: 8 June 2016 Accepted: 23 September 2016
References
Andre, J., & Rogers, S. (2006). Using verbal and blind-walking distance estimates
to investigate the two visual systems hypothesis. Perception & Psychophysics,
68(3), 353–361.
Bach, D. R., Furl, N., Barnes, G., & Dolan, R. J. (2015). Sustained magnetic responses
in temporal cortex reflect instantaneous significance of approaching and
receding sounds. PLoS One, 10(7), e0134060.
Bach, D. R., Neuhoff, J. G., Perrig, W., & Seifritz, E. (2009). Looming sounds as
warning signals: The function of motion cues. International Journal of
Psychophysiology, 74(1), 28–33. doi:10.1016/j.ijpsycho.2009.06.004
Bach, D. R., Schachinger, H., Neuhoff, J. G., Esposito, F., Di Salle, F., Lehmann, C., . . .
Seifritz, E. (2008). Rising sound intensity: An intrinsic warning cue activating the
amygdala. Cerebral Cortex, 18(1), 145–150. doi:10.1093/cercor/bhm040
Buhrmester, M., Kwang, T., & Gosling, S. D. (2011). Amazon’s mechanical Turk: A
new source of inexpensive, yet high-quality, data? Perspectives on
Psychological Science, 6(1), 3–5. doi:10.1177/1745691610393980
Canevet, G., Teghtsoonian, R., & Teghtsoonian, M. (2003). A comparison of
loudness change in signals that continuously rise or fall in amplitude. Acta
Acustica United with Acustica, 89(2), 339–345.
Cappe, C., Thelen, A., Romei, V., Thut, G., & Murray, M. M. (2012). Looming signals
reveal synergistic principles of multisensory integration. Journal of
Neuroscience, 32(4), 1171–1182. doi:10.1523/jneurosci.5517-11.2012
Carlile, S., & Best, V. (2002). Discrimination of sound source velocity in human
listeners. Journal of the Acoustical Society of America, 111(2), 1026–1035. doi:
10.1121/1.1436067
Carlile, S., & Leung, J. (2016). The perception of auditory motion. Trends in
Hearing, 20, 2331216516644254. doi:10.1177/2331216516614254
Cauchoix, M., & Chaine, A. S. (2016). How can we study the evolution of animal
minds? Frontiers in Psychology, 7, 18. doi:10.3389/fpsyg.2016.00358
Neuhoff Cognitive Research: Principles and Implications (2016) 1:15 Page 7 of 9
Croston, R., Branch, C. L., Kozlovsky, D. Y., Dukas, R., & Pravosudov, V. V. (2015).
Heritability and the evolution of cognitive traits. Behavioral Ecology, 26(6),
1447–1459. doi:10.1093/beheco/arv088
Crump, M. J. C., McDonnell, J. V., & Gureckis, T. M. (2013). Evaluating Amazon’s
mechanical Turk as a tool for experimental behavioral research. PLoS One,
8(3), e57410. doi:10.1371/journal.pone.0057410
Edwards, M., & Ibbotson, M. R. (2007). Relative sensitivities to large-field optic-flow
patterns varying in direction and speed. Perception, 36(1), 113–124. doi:10.
1068/p5626
Fletcher, P. D., Nicholas, J. M., Shakespeare, T. J., Downey, L. E., Golden, H. L.,
Agustus, J. L., . . . Warren, J. D. (2015). Dementias show differential
physiological responses to salient sounds. Frontiers in Behavioral Neuroscience,
9, 73. doi:10.3389/fnbeh.2015.00073
Freeman, T. C. A., Leung, J., Wufong, E., Orchard-Mills, E., Carlile, S., & Alais, D.
(2014). Discrimination contours for moving sounds reveal duration and
distance cues dominate auditory speed perception. PLoS One, 9(7), e102864.
doi:10.1371/journal.pone.0102864
Freiberg, K., Tually, K., & Crassini, B. (2001). Use of an auditory looming task to test
infants’sensitivity to sound pressure level as an auditory distance cue. British
Journal of Developmental Psychology, 19,1–10. doi:10.1348/026151001165903
Gardner, W. G., & Martin, K. D. (1995). HRTF measurements of a KEMAR. Journal of
the Acoustical Society of America, 97(6), 3907–3908. doi:10.1121/1.412407
Ghazanfar, A. A., & Maier, J. X. (2009). Rhesus monkeys (Macaca mulatta) hear
rising frequency sounds as looming. Behavioral Neuroscience, 123(4), 822–827.
doi:10.1037/a0016391
Ghazanfar, A. A., Neuhoff, J. G., & Logothetis, N. K. (2002). Auditory looming
perception in rhesus monkeys. Proceedings of the National Academy of
Sciences of the United States of America, 99(24), 15755–15757. doi:10.1073/
pnas.242469699
Glatz, C., Bulthoff, H. H., & Chuang, L. L. (2014). Looming auditory warnings
initiate earlier event-related potentials in a manual steering task. Cognitive
Processing, 15(1), S38–S38.
Gordon, M. S., & Rosenblum, L. D. (2005). Effects of intrastimulus modality change
on audiovisual time-to-arrival judgments. Perception & Psychophysics, 67(4),
580–594. doi:10.3758/bf03193516
Grantham, D. W. (1997). Auditory motion perception: Snapshots revisited. In R. H.
Gilkey & T. R. Anderson (Eds.), Binaural and spatial hearing in real and virtual
environments. Hillsdale, NJ: Lawrence Erlbaum Associates, Inc.
Grassi, M. (2010). Sex difference in subjective duration of looming and receding
sounds. Perception, 39(10), 1424–1426. doi:10.1068/p6810
Guski, R. (1992). Acoustic tau: An easy analogue to visual tau? Ecological
Psychology, 4, 189–197.
Haselton, M. G., Bryant, G. A., Wilke, A., Frederick, D. A., Galperin, A., Frankenhuis,
W. E., & Moore, T. (2009). Adaptive rationality: an evolutionary perspective on
cognitive bias. Social Cognition, 27(5), 733–763.
Haselton, M. G., & Buss, D. M. (2000). Error management theory: A new
perspective on biases in cross-sex mind reading. Journal of Personality and
Social Psychology, 78(1), 81–91. doi:10.1037/0022-3514.78.1.81
Haselton, M. G., & Nettle, D. (2006). The paranoid optimist: An integrative
evolutionary model of cognitive biases. Personality and Social Psychology
Review, 10(1), 47–66. doi:10.1207/s15327957pspr1001_3
Holden, C. J., Dennie, T., & Hicks, A. D. (2013). Assessing the reliability of the M5-
120 on Amazon’s mechanical Turk. Computers in Human Behavior, 29(4),
1749–1754. doi:10.1016/j.chb.2013.02.020
Ingham, N. J., Hart, H. C., & McAlpine, D. (2001). Spatial receptive fields of inferior
colliculus neurons to auditory apparent motion in free field. Journal of
Neurophysiology, 85(1), 23–33.
Lewis, C. F., & McBeath, M. K. (2004). Bias to experience approaching motion in a
three-dimensional virtual environment. Perception, 33(3), 259–276. doi:10.
1068/p5190
Locke, S. M., Leung, J., & Carlile, S. (2016). Sensitivity to auditory velocity contrast.
Scientific Reports, 6, 5. doi:10.1038/srep27725
Maier, J. X., Chandrasekaran, C., & Ghazanfar, A. A. (2008). Integration of bimodal
looming signals through neuronal coherence in the temporal lobe. Current
Biology, 18(13), 963–968. doi:10.1016/j.cub.2008.05.043
Maier, J. X., & Ghazanfar, A. A. (2007). Looming biases in monkey auditory cortex.
Journal of Neuroscience, 27(15), 4093–4100. doi:10.1523/jneurosci.0330-07.2007
Maier, J. X., Neuhoff, J. G., Logothetis, N. K., & Ghazanfar, A. A. (2004). Multisensory
integration of looming signals by Rhesus monkeys. Neuron, 43(2), 177–181.
doi:10.1016/j.neuron.2004.06.027
McBeath, M. K., Shaffer, D. M., & Kaiser, M. K. (1995). How baseball outfielders
determine where to run to catch fly balls. Science, 268(5210), 569–573. doi:10.
1126/science.7725104
McGuire, A. B., Gillath, O., & Vitevitch, M. (2016). Effects of mental resource
availability on looming task performance. Attention, Perception, &
Psychophysics, 78, 107–113.
Morrongiello, B. A., Hewitt, K. L., & Gotowiec, A. (1991). Infants discrimination of
relative distance in the auditory modality - approaching versus receding
sound sources. Infant Behavior & Development, 14(2), 187–208. doi:10.1016/
0163-6383(91)90005-d
Mueller, A. S., & Timney, B. (2014). Effects of radial direction and eccentricity on
acceleration perception. Perception, 43(8), 805–810. doi:10.1068/p7776
National Highway Traffic Safety Administration. (2015). Traffic Safety Facts 2013
Data - Pedestrians. Retrieved from Washington, DC: http://www-nrd.nhtsa.dot.
gov/Pubs/812124.pdf
Neuhoff, J. G. (1998). Perceptual bias for rising tones. Nature, 395(6698), 123–124.
doi:10.1038/25862
Neuhoff, J. (1999). Perception of changes in loudness - Reply. Nature, 398(6729),
673–674. doi:10.1038/19446
Neuhoff, J. G. (2001). An adaptive bias in the perception of looming auditory
motion. Ecological Psychology, 13,87–110.
Neuhoff, J. G., Hamilton, G. R., Gittleson, A. L., & Mejia, A. (2014). Babies in traffic:
Infant vocalizations and listener sex modulate auditory motion perception.
Journal of Experimental Psychology-Human Perception and Performance, 40(2),
775–783. doi:10.1037/a0035071
Neuhoff, J. G., Long, K. L., & Worthington, R. C. (2012). Strength and physical
fitness predict the perception of looming sounds. Evolution and Human
Behavior, 33(4), 318–322. doi:10.1016/j.evolhumbehav.2011.11.001
Neuhoff, J. G., Planisek, R., & Seifritz, E. (2009). Adaptive sex differences in auditory
motion perception: Looming sounds are special. Journal of Experimental
Psychology-Human Perception and Performance, 35(1), 225–234. doi:10.1037/
a0013159
Paolacci, G., Chandler, J., & Ipeirotis, P. G. (2010). Running experiments on
Amazon Mechanical Turk. Judgment and Decision Making, 5(5), 411–419.
Recarte, M. A., Conchillo, A., & Nunes, L. M. (2000). Perception of Speed and
Increments in Cars. Berne, Switzerland: Paper presented at the International
Conference on Traffic and Transport Psychology.
Recarte, M. A., & Nunes, L. M. (1996). Perception of speed in automobile:
Estimation and production. Journal of Experimental Psychology-Applied, 2(4),
291–304.
Regan, D., & Vincent, A. (1995). Visual processing of looming and time to contact
throughout the visual-field. Vision Research, 35(13), 1845–1857. doi:10.1016/
0042-6989(94)00274-p
Riskind, J. H., Kleiman, E. M., Seifritz, E., & Neuhoff, J. G. (2014). Influence of anxiety,
depression and looming cognitive style on auditory looming perception.
Journal of Anxiety Disorders, 28(1), 45–50. doi:10.1016/j.janxdis.2013.11.005
Rosenblum, L. D. (2008). Speech perception as a multimodal phenomenon.
Current Directions in Psychological Science, 17(6), 405–409. doi:10.1111/j.1467-
8721.2008.00615.x
Rosenblum, L. D., Carello, C., & Pastore, R. E. (1987). Relative effectiveness of 3
stimulus variables for locating a moving sound source. Perception, 16(2), 175–
186. doi:10.1068/p160175
Rosenblum, L. D., Gordon, M. S., & Wuestefeld, A. P. (2000). Effects of performance
feedback and feedback withdrawal on auditory looming perception.
Ecological Psychology, 12(4), 273–291. doi:10.1207/s15326969eco1204_02
Rosenblum, L. D., Wuestefeld, A. P., & Saldana, H. M. (1993). Auditory looming
perception - influences on anticipatory judgments. Perception, 22(12), 1467–
1482. doi:10.1068/p221467
Schiff, W., & Oldak, R. (1990). Accuracy of judging time to arrival - effects of
modality, trajectory, and gender. Journal of Experimental Psychology-Human
Perception and Performance, 16, 2. doi:10.1037/0096-1523.16.2.303
Scott, T. R., Lavender, A. D., McWhirt, R. A., & Powell, D. A. (1966). Directional
asymmetry of motion aftereffect. Journal of Experimental Psychology, 71(6),
806. doi:10.1037/h0023194
Seifritz, E., Neuhoff, J. G., Bilecen, D., Scheffler, K., Mustovic, H., Schachinger, H., . . .
Di Salle, F. (2002). Neural processing of auditory looming in the human brain.
Current Biology, 12, 24. doi:10.1016/s0960-9822(02)01356-8
Senna, I., Parise, C. V., & Ernst, M. O. (2015). Hearing in slow-motion: Humans
underestimate the speed of moving sounds. Scientific Reports, 5, 14054. doi:
10.1038/srep14054
Neuhoff Cognitive Research: Principles and Implications (2016) 1:15 Page 8 of 9
Tajadura-Jimenez, A., Valjamae, A., Asutay, E., & Vastfjall, D. (2010). Embodied
auditory perception: The emotional impact of approaching and receding
sound sources. Emotion, 10(2), 216–229. doi:10.1037/a0018422
Teghtsoonian, R., Teghtsoonian, M., & Canevet, G. (2005). Sweep-induced
acceleration in loudness change and the "bias for rising intensities".
Perception & Psychophysics, 67(4), 699–712. doi:10.3758/bf03193526
Triggs, T. J., & Berenyi, J. S. (1982). Estimation of automobile speed under day and
night conditions. Human Factors, 24(1), 111–114.
Warren, R. M. (1981). Measurement of sensory intensity. Behavioral and Brain
Sciences, 4(2), 175–189.
Warren, J. D., Zielinski, B. A., Green, G. G. R., Rauschecker, J. P., & Griffiths, T. D.
(2002). Perception of sound-source motion by the human brain. Neuron,
34(1), 139–148. doi:10.1016/s0896-6273(02)00637-2
Wilson, W. W., & O’Neill, W. E. (1998). Auditory motion induces directionally
dependent receptive field shifts in inferior colliculus neurons. Journal of
Neurophysiology, 79(4), 2040–2062.
Witten, I. B., Bergan, J. F., & Knudsen, E. I. (2006). Dynamic shifts in the owl’s
auditory space map predict moving sound location. Nature Neuroscience,
9(11), 1439–1445. doi:10.1038/nn1781
Submit your manuscript to a
journal and benefi t from:
7 Convenient online submission
7 Rigorous peer review
7 Immediate publication on acceptance
7 Open access: articles freely available online
7 High visibility within the fi eld
7 Retaining the copyright to your article
Submit your next manuscript at 7 springeropen.com
Neuhoff Cognitive Research: Principles and Implications (2016) 1:15 Page 9 of 9
