mteb/BrightProPsychologyRetrieval huggingface dataset:
Through the examination of data, the development of ear asymmetry was apparent
throughout the stages of embryonic development. The ears appeared slit-like at
stage 29 of embryonic development and took on the  ellipsoid
 shape at stage 32, which is also when outer ear
development began. Dorso-occipital movement of the outer ear began
symmetrically at stage 34, but asymmetry rapidly increased from this dorso-
occipital movement by stage 37. Surface area between stages 32 and 35 was
0.4-0.5 mm2, with  eccentricity 
"Eccentricity \(mathematics\)") between the right and left ear differing by
less than 0.1 mm. Between stages 36 and 37, the surface area was 0.6-1.9 mm2.
[9]  Eccentricity was no longer measured after stage 37 since the ear-opening
shapes were no longer ellipsoid. The rostral margin of the ear opening started
to flatten at stage 38, with the higher ear on the head having more dorso-
ventral flattening. The angle of flattening margins at stage 38 differed by
18.5 degrees, but by only 16 degrees at stage 39. Ear asymmetry did not
increase between stages 40 and 41, as ear asymmetry reached maximum at stage
39. The margin differed by 21 degrees at stage 40 and by 33 degrees at stage
41.
External links  

*  Calculation of phase angle (phase difference) from time delay (time of arrival ITD) and frequency 

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Conservation science in action.
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The  axons  of the  auditory nerve
 originate from the hair cells of the
cochlea in the inner ear. Different sound frequencies are encoded by different
fibers of the auditory nerve, arranged along the length of the auditory nerve,
but codes for the timing and level of the sound are not segregated within the
auditory nerve. Instead, the ITD is encoded by  phase locking
 , i.e. firing at or near a particular
phase angle of the sinusoidal stimulus sound wave, and the IID is encoded by
spike rate. Both parameters are carried by each fiber of the auditory nerve.
[15]
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##  Topics
An American pelican
swallowing a carp. © Wayne Watson, USFWS /  Flickr
2. **Lenore Elliott** says:
References  

1. ** ^  ** Jan Schnupp, Israel Nelken and Andrew King (2011).  _Auditory Neuroscience_  . MIT Press.  ISBN  "ISBN \(identifier\)")  978-0-262-11318-2   . Archived from  the original  on 2011-01-29  . Retrieved  2011-04-14  .

* Franken TP, Roberts MT, Wei L, NL NLG, Joris PX. In vivo coincidence detection in mammalian sound localization generates phase delays. Nature neuroscience. 2015;18(3):444-452. doi:10.1038/nn.3948.
July 23, 2021
*  Three New Field Guides for Bird & Weather Nerds
4. **Toi Tomas** says:
Researchers have studied the embryonic development of ear asymmetry in the
American barn owl ( _Tyto furcata pratincola_ ) in the frame of 42 different
stages of embryonic development. The experiment began by taking 19 embryos
from the Institute of Biology to  RWTH Aachen University
 . The embryos were
either raised by the hen or were incubated in a Compact S84. The embryos
utilized in the study were between stage 29 and stage 41 of embryonic
development, with those between stages 36-39 being examined a bit more
frequently than others.  [8]  Micro  CT-scans 
were used to measure the asymmetry of the ear during development, with some
scans being taken using the Skyscan 1172. Aluminum filters were used to
optimize image quality and phosphotungstic acid (PTA) was used to enhance soft
tissue extract in the embryos. Markers were set on the embryonic heads to
track differential growth. NRecon was used to reconstruct raw data, three-
dimensional objects were calculated in Reconstruct, photographs were produced
in Blender, and all final figures were constructed with Matlab and CorelDraw
X6. The center of the ear opening, squamosum,  stapes  , eye lens, nose, and  premaxilla 
were all tracked in the study. The cervical vertebra (C1) and the  pituitary
gland  were used to define the
anatomical coordinate system. Measurements of the ear-opening, surface area of
the ear, and eccentricity were derived using various equations.
7. **Graeme** says:
##  How ears asymmetry develops
Cara Cannon Byington
The Nature Conservancy Website
Distance of the sound source  

[ _ citation needed   _ ]

The human auditory system has only limited possibilities to determine the
distance of a sound source. In the close-up-range there are some indications
for distance determination, such as extreme level differences (e.g. when
whispering into one ear) or specific  pinna  "Pinna
\(anatomy\)") (the visible part of the ear) resonances in the close-up range.

The auditory system uses these clues to estimate the distance to a sound
source:

* Direct/ Reflection ratio: In enclosed rooms, two types of sound are arriving at a listener: The direct sound arrives at the listener's ears without being reflected at a wall. Reflected sound has been reflected at least one time at a wall before arriving at the listener. The ratio between direct sound and reflected sound can give an indication about the distance of the sound source.
* Loudness: Distant sound sources have a lower loudness than close ones. This aspect can be evaluated especially for well-known sound sources.
* Sound spectrum: High frequencies are more quickly damped by the air than low frequencies. Therefore, a distant sound source sounds more muffled than a close one, because the high frequencies are attenuated. For sound with a known spectrum (e.g. speech) the distance can be estimated roughly with the help of the perceived sound.
* ITDG: The Initial Time Delay Gap describes the time difference between arrival of the direct wave and first strong reflection at the listener. Nearby sources create a relatively large ITDG, with the first reflections having a longer path to take, possibly many times longer. When the source is far away, the direct and the reflected sound waves have similar path lengths.
* Movement: Similar to the visual system there is also the phenomenon of motion  parallax  in acoustical perception. For a moving listener nearby sound sources are passing faster than distant sound sources.
* Level Difference: Very close sound sources cause a different level between the ears.
The pelicans in London’s popular St. James Park are fed fish by
groundskeepers. But they are known to supplement this diet by gulping down
city pigeons – sometimes to the horror of tourists. There have been plenty of
other documented instances of pelicans eating ducks and gulls. A large bird
struggling around a pelican’s throat patch is not a pleasant sight. But it’s
become  a staple of YouTube videos
 .
##  Significance of asymmetrical ears for localization of elevation
6. **Rhetta Jack** says:
The world’s eight pelican species are famous for their beaks and large throat
pouches. They use these beaks to scoop up fish. American white pelicans focus
mainly on small fish, but  according to the Cornell Lab of Ornithology
 ,
they are quite opportunistic. They will switch to the most abundant prey, like
spawning cutthroat trout in the Rocky Mountain West or salamanders and
crayfish in the Midwest.
Parallel
processing pathways in the brain for time and level for sound localization in
the owl
Different methods for measuring ITDs  

* For an abrupt stimulus such as a click, onset ITDs are measured. An onset ITD is the time difference between the onset of the signal reaching two ears.
* A transient ITD can be measured when using a random noise stimulus and is calculated as the time difference between a set peak of the noise stimulus reaching the ears.
* If the stimulus used is not abrupt but periodic then ongoing ITDs are measured. This is where the waveforms reaching both ears can be shifted in time until they perfectly match up and the size of this shift is recorded as the ITD. This shift is known as the interaural phase difference (IPD) and can be used for measuring the ITDs of periodic inputs such as pure tones and amplitude modulated stimuli. An amplitude modulated stimulus IPD can be assessed by looking at either the waveform  envelope  or the waveform  fine structure  .
Owls tend to have asymmetric ears, with the openings being placed just behind
the eyes. The shape of the ear opening, known as the  aperture
 , depends on the species. In some species, the
opening has a valve, called an  operculum 
"Operculum \(animal\)") , covering it. The left ear opening is typically
positioned a bit higher than the right ear opening to aid with sound
localization and the detection of prey, even in the dark. During flight, the
left ear receives sounds from below them and the right ear receives sounds
from above them. The feathers on the edge of barn owl’s face creates a disc
that works to trap and focus sound, similar to the outer ears of humans. The
sound waves travel through the owl’s ear canal until they reach the eardrum,
through the ossicles, and into the inner ear so that the owl is able to
perceive exactly where their prey is located. As owls depend on their ability
to track prey using their super sense of hearing in order to survive, it is
important to understand the structures of the ear of barn owls that work to
transmit these sounds.
Justine E. Hausheer
Multichannel stereo virtual reproduction  

Since the multichannel stereo systems require many reproduction channels, some
researchers adopted the HRTF simulation technologies to reduce the number of
reproduction channels.  [25]  They use only two speakers to simulate multiple
speakers in a multichannel system. This process is called as virtual
reproduction. Essentially, such approach uses both interaural difference
principle and pinna filtering effect theory. Unfortunately, this kind of
approach cannot perfectly substitute the traditional multichannel stereo
system, such as  5.1  /  7.1 surround sound
 system. That is because when
the listening zone is relatively larger, simulation reproduction through HRTFs
may cause invert acoustic images at symmetric positions.
Further reading  

* Feddersen, W. E., Sandel, T. T., Teas, D. C.,  Jeffress, L. A.  (1957) Localization of high frequency tones. _Journal of the Acoustical Society of America_ . 29: 988–991.
* Fitzpatrick, D. C., Batra, R., Kuwada, S. (1997). Neurons Sensitive to InterauralTemporal Disparities in the Medial Part of the Ventral Nucleus of the Lateral Lemniscus. _The Journal of Neurophysiology._ 78: 511–515.
* Gelfand, S. A. (2004) _Hearing: An Introduction to Psychological and Physiological Acoustics_ . 4th Edition New York: Marcel Dekker.
* Kuwada, S., Fitzpatrick, D. C., Batra, R., Ostapoff, E. M. ( 2005). Sensitivity to Interaural Time Difference in the Dorsal Nucleus of the Lateral Lemniscus of the Unanesthetized Rabbit: Comparison with other structures. _Journal of Neurophysiology_ . 95: 1309–1322.
* Moore, B. (1996) Perceptual Consequences of Cochlear Hearing Loss and their Implications for the Design of Hearing Aids. _Ear and Hearing_ . 17(2):133-161
* Moore, B. C. (2004) _An Introduction to the Psychology of Hearing_ . 5th Edition London: Elsevier Academic Press.
* Woodworth, R. S. (1938) _Experimental Psychology_ . New York: Holt, Rinehart, Winston.
* Yost, W. A. (2000) _Fundamentals of Hearing: An Introduction_ . 4th Edition San Diego: Academic Press.
1. **Carmela McCain Simmons** says:
Lisa Ballard
August 26, 2021
Waves
"Sound") between two ears contributes to  auditory processing
 in such a way as to enable
sound localization and direction was considerably advanced after the invention
of the  stethophone  by  Somerville Scott
Alison ") in 1859, who coined the
term 'binaural'. Alison based the stethophone on the  stethoscope
 , which had been invented by  René
Théophile Hyacinthe Laennec 
(1781–1826); the stethophone had two separate "pickups", allowing the user to
hear and compare sounds derived from two discrete locations.  [35]
*  Mammals, Wildlife Trade + the Next Global Pandemic
In the median plane (front, above, back, below)  ") ]

For many mammals there are also pronounced structures in the pinna near the
entry of the ear canal. As a consequence, direction-dependent resonances can
appear, which could be used as an additional localization cue, similar to the
localization in the median plane in the human auditory system. There are
additional localization cues which are also used by animals.
#  6 Surprising Tales of Predatory Birds
Interaural time difference

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* ###  Vampire Finches
The kelp gulls pull off strips of flesh and blubber
 from southern right whales off the Valdes
Peninsula in Argentina. They target the whales when they come up for air. This
behavior was first documented in 1972, when it was a rare occurrence. That
changed rapidly. By 2008, 77 percent of the whales in the area had suffered
wounds from feeding gulls.
##  Anatomy of the ear
June 24, 2021
* ###  Activities
When you first notice a great blue heron along a pond, it’s the very picture
of stillness. Suddenly, it strikes, likely bringing up a minnow or frog. The
heron will also strike much larger prey, often impaling it instead of
immediately swallowing.  As Cornell notes
 , herons
“use their dagger-like bills to impale larger fish, often shaking them to
break or relax the sharp spines before gulping them down.
Cool Green Science
Show comments (7)
Localization with coupled ears (flies)  ") ]

The tiny parasitic fly _ Ormia ochracea  _ has become a  model organism  in sound localization experiments because of its unique  ear
 . The animal is too small for the time difference of sound
arriving at the two ears to be calculated in the usual way, yet it can
determine the direction of sound sources with exquisite precision. The 
tympanic membranes  of opposite
ears are directly connected mechanically, allowing resolution of sub-
microsecond time differences  [27]  [28]  and requiring a new  neural coding
 strategy.  [29]  Ho  [30]  showed that
the coupled-eardrum system in frogs can produce increased interaural vibration
disparities when only small  arrival time  and sound level differences were available to the animal's head.
Efforts to build directional microphones based on the coupled-eardrum
structure are underway.
Pinna filtering effect  

 HRTF

Duplex theory shows that ITD and IID play significant roles in sound
localization, but they can only deal with lateral localization problems. For
example, if two acoustic sources are placed symmetrically at the front and
back of the right side of the human head, they will generate equal ITDs and
IIDs, in what is called the cone model effect. However, human ears can still
distinguish between these sources. Besides that, in natural sense of hearing,
one ear alone, without any ITD or IID, can distinguish between them with high
accuracy. Due to the disadvantages of duplex theory, researchers proposed the
pinna filtering effect theory.  [14]  [15]  The shape of human pinna is
concave with complex folds and asymmetrical both horizontally and vertically.
Reflected and direct waves generate a frequency spectrum on the eardrum,
relating to the acoustic sources. Then auditory nerves localize the sources
using this frequency spectrum.  [16]

 HRIR

These spectrum clues generated by the pinna filtering effect can be presented
as a  head-related transfer function  (HRTF). The corresponding time domain
expressions are called the Head-Related Impulse Response (HRIR). The HRTF is
also described as the transfer function from the free field to a specific
point in the ear canal. We usually recognize HRTFs as LTI systems:  [8]

H  L  =  H  L  (  r  ,  θ  ,  φ  ,  ω  ,  α  )  =  P  L  (  r  ,  θ  ,  φ  ,
ω  ,  α  )  /  P  0  (  r  ,  ω  )  {\displaystyle H_{L}=H_{L}(r,\theta
,\varphi ,\omega ,\alpha )=P_{L}(r,\theta ,\varphi ,\omega ,\alpha
)/P_{0}(r,\omega )}

H  R  =  H  R  (  r  ,  θ  ,  φ  ,  ω  ,  α  )  =  P  R  (  r  ,  θ  ,  φ  ,
ω  ,  α  )  /  P  0  (  r  ,  ω  )  ,  {\displaystyle H_{R}=H_{R}(r,\theta
,\varphi ,\omega ,\alpha )=P_{R}(r,\theta ,\varphi ,\omega ,\alpha
)/P_{0}(r,\omega ),}

where L and R represent the left ear and right ear respectively,  P  L
{\displaystyle P_{L}}  
and  P  R  {\displaystyle P_{R}}  
represent the amplitude of the sound pressure at the entrances to the left and
right ear canals, and  P  0  {\displaystyle P_{0}}  
is the amplitude of sound pressure at the center of the head coordinate when
listener does not exist. In general, an HRTF's  H  L  {\displaystyle H_{L}}

and  H  R  {\displaystyle H_{R}}  
are functions of source angular position  θ  {\displaystyle \theta }

, elevation angle  φ  {\displaystyle \varphi }  
, the distance between the source and the center of the head  r
{\displaystyle r}  
, the angular velocity  ω  {\displaystyle \omega }  
and the equivalent dimension of the head  α  {\displaystyle \alpha }

.

At present, the main institutes that work on measuring HRTF database include
CIPIC  [17]  International Lab, MIT Media Lab, the Graduate School in
Psychoacoustics at the University of Oldenburg, the Neurophysiology Lab at the
University of Wisconsin–Madison and Ames Lab of NASA. Databases of HRIRs from
humans with normal and impaired hearing and from animals are publicly
available.
Head tilting  

For sound localization in the median plane (elevation of the sound) also two
detectors can be used, which are positioned at different heights. In animals,
however, rough elevation information is gained simply by tilting the head,
provided that the sound lasts long enough to complete the movement. This
explains the innate behavior of  [ _ vague   _ ]  cocking the head to one side when trying to
localize a sound precisely. To get instantaneous localization in more than two
dimensions from time-difference or amplitude-difference cues requires more
than two detectors.
##  7 comments
*  Neuroethology 
*  Hearing 
*  Sound 
*  Owls
###  Legal Information
Published on  June 21, 2021
See also  

*  Acoustic location 
*  Animal echolocation 
*  Binaural fusion 
*  Coincidence detection in neurobiology 
*  Human echolocation 
*  Perceptual-based 3D sound localization 
*  Psychoacoustics 
*  Spatial hearing loss
3D para-virtualization stereo system  

The representatives of this kind of system are SRS Audio Sandbox, Spatializer
Audio Lab and  Qsound  Qxpander.  [25]  They use HRTF
to simulate the received acoustic signals at the ears from different
directions with common binary-channel stereo reproduction. Therefore, they can
simulate reflected sound waves and improve subjective sense of space and
envelopment. Since they are para-virtualization stereo systems, the major goal
of them is to simulate stereo sound information. Traditional stereo systems
use sensors that are quite different from human ears. Although those sensors
can receive the acoustic information from different directions, they do not
have the same frequency response of human auditory system. Therefore, when
binary-channel mode is applied, human auditory systems still cannot feel the
3D sound effect field. However, the 3D para-virtualization stereo system
overcome such disadvantages. It uses HRTF principles to glean acoustic
information from the original sound field then produce a lively 3D sound field
through common earphones or speakers.
Animals  

Since most animals have two ears, many of the effects of the human auditory
system can also be found in other animals. Therefore, interaural time
differences (interaural phase differences) and interaural level differences
play a role for the hearing of many animals. But the influences on
localization of these effects are dependent on head sizes, ear distances, the
ear positions and the orientation of the ears. Smaller animals like insects
use different techniques as the separation of the ears are too small.  [26]
For the process of animals emitting sound to improve localization, a
biological form of  active sonar  , see 
animal echolocation  .
An American crow. © Fyn
Kynd /  Flickr
In the time pathway, the nucleus laminaris (mammalian medial superior olive)
is the first site of binaural convergence. It is here that ITD is detected and
encoded using neuronal  delay lines  and  coincidence detection
 , as in the  Jeffress model
 ; when
phase-locked impulses coming from the left and right ears coincide at a
laminaris neuron, the cell fires most strongly. Thus, the nucleus laminaris
acts as a delay-line coincidence detector, converting distance traveled to
time delay and generating a map of interaural time difference. Neurons from
the nucleus laminaris project to the core of the central nucleus of the
inferior colliculus and to the anterior lateral lemniscal nucleus.
##  Cool Green Science Newsletter
June 29, 2021
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"
As ornithologist Joe Smith writes
 , “In search of protein, they move about the woods like a pack
of velociraptors, thrashing up the leaf litter and eating anything that
moves.”
###  Join the Discussion   Cancel reply
History  

The term 'binaural' literally signifies 'to hear with two ears', and was
introduced in 1859 to signify the practice of listening to the same sound
through both ears, or to two discrete sounds, one through each ear. It was not
until 1916 that  Carl Stumpf  (1848–1936),
a German  philosopher  and  psychologist
 , distinguished between dichotic
listening, which refers to the stimulation of each ear with a different 
stimulus  "Stimulus \(physiology\)") , and
diotic listening, the simultaneous stimulation of both ears with the same
stimulus.  [33]

Later, it would become apparent that binaural hearing, whether dichotic or
diotic, is the means by which sound localization occurs.  [33]  [34]  [ _
page needed   _ ]

Scientific consideration of binaural hearing began before the phenomenon was
so named, with speculations published in 1792 by  William Charles Wells
 (1757–1817) based on
his research into  binocular vision  .  [35]   Giovanni Battista Venturi
 (1746–1822)
conducted and described experiments in which people tried to localize a sound
using both ears, or one ear blocked with a finger. This work was not followed
up on, and was only recovered after others had worked out how human sound
localization works.  [33]  [35]   Lord Rayleigh
 (1842–1919) would do these same experiments and come to the
results, without knowing Venturi had first done them, almost seventy-five
years later.  [35]

 Charles Wheatstone 
(1802–1875) did work on optics and color mixing, and also explored hearing. He
invented a device he called a "microphone" that involved a metal plate over
each ear, each connected to metal rods; he used this device to amplify sound.
He also did experiments holding  tuning forks  to both ears at the same time, or separately, trying to work out how
sense of hearing works, that he published in 1827.  [35]   Ernst Heinrich
Weber  (1795–1878) and 
August Seebeck  (1805–1849) and 
William Charles Wells 
also attempted to compare and contrast what would become known as binaural
hearing with the principles of binocular integration generally.  [35]

Understanding how the differences in [ sound signals ](/wiki/Sound