Auditory Perception - Science topic

By embedding a tone in noise, you can reduce (unnecessary) effects of external and internal noise. There is always external noise in your measurement environment, and it is difficult to completely remove it. There is always internal noise, coming from inside a listener. You can control them by adding noise of sufficient intensity. In theory, the slope of psychometric function become shallower when the nose is added, since the slope reflects the noise variance.

You can not exclude the patients with anxiety and speech delay, since these are autistic feautures according to the DSM-V. It's hard to select patients with pure autism, because it always comorbid with other disorder such as ID, Epilepsy, regression, without neglecting the "syndromic autism". So you may just exclude the ADHD patients since it's a disorder that could influence your results and statistics.

You are especially kind and gentle, Thank you...I'll look for some dear Isabel

As a Belgium-based researcher, I can recommend asking a colleague from a university in the Dutch-speaking area (Flanders and the Netherlands) for permission to post your call for participants on one of their general message boards. KU Leuven, the University of Antwerp, and any 'Hogeschool' could be of help. Students know the importance of surveys, and while the turnout response may be fairly low, it would certainly increase your engagement and help your study. Facebook pages of certain Flemish and Dutch cities might also allow messages for research purposes. Of course, you would have to keep in mind to preserve the representational balance in your (control) group. This apply to both the age/ level of education a large number of students would represent, as to the cultural and linguistic differences between members of the Flemish and Dutch participants respectively (not to mention the significant differences between speakers from different Flemish provinces).

If I may ask, how many people would you need to comfortably conduct your study?

Isabel,

I know of many studies on when phoneme detectors develop but never thought about your question.

Are we even sure that people perform speaker normalization in the same sense that speech recognition systems do (or at least used to before deep learning)?

Since we do know that one of the early layers of human speech recognition processing produces a sequence of best phoneme guesses, and higher layers can force backtracking to try the next best guesses, it is possible to check psychophysically if there is such a normalization at lower layers by checking the processing speed, and if there is a change in processing speed after normalization takes place.

It is also an interesting question how the speaker recognition and speech recognition processes are related. Do we first recognize the speaker and then apply that speaker's phoneme recognizers? I remember reading a paper a few years ago about recognizing accents before recognizing speech (but can't find the reference).

Another clue is Hearing different accents at home impacts language processing in infants from U Buffalo (www.sciencedaily.com/releases/2017/12/171205104127.htm ) which found that infants exposed to multiple accents before 12 months develop different recognition strategies. See also the JASA reference there and

Linguistic processing of accented speech across the lifespan (www.frontiersin.org/articles/10.3389/fpsyg.2012.00479/full).

Finally Language Discrimination by English-Learning 5-Month-Olds: Effects of Rhythm and Familiarity (labfon.letras.ulisboa.pt/personal/sfrota/aeli/Nazzi_Jusczyk_Johnson_2000.pdf) may be of use.

Would love to hear what you learn!

Y(J)S

Thanks very much, Prof. Peter Narins! Much appreciated.

Tinnitus volume may fluctuate with certain eye movement -intermittently-, jaw & neck movement including teeth grinding and yawning.

If :played back "means sounding all at once in the same place, your question devolves mathematically into asking how many numbers can sum to, say, 3.  Mathematicians are inclined to invoke such ideas as infinity in such cases, though the answer is clearly larger than we can name.

If you at what point does adding yet another sound to a large mix become irrelevant, the answer is also clearly large, but far from infinite.  Having sung in large choruses, I opine that after about a hundred or two voice, the addition (or subtraction) one more (or less) hardly matters in any musical sense.  (The gospel choir at UCSD once numbered over 500, but their major problem was finding a space in which they could rehearse).

The interesting part of your question lies in between 0 and infinity.  Modern psycholofy and cognitive science both suggest that  7 plus or minus 2 is about the limit of our "attention".  But they also suggest we don't multitask, but scan, i.e., shift our focused attention rapidly among competing messages.  Any instrument-rated pilot can tell you that simultaneously scanning (meaning observing and understanding) 7 or so instruments (as well as looking out the window) stretches human capabilities.  Not impossible, but difficult, especially if your life depends on it.

So even though I can't truly answer your question, my best guess would be the well-established psychological number associated with short-term memory: seven plus or minus two.  Seems our brain - evolved over million of years - have figured that before that number, we stand a chance to figure things out.  After that number, run!

As promised, here is the article that I'll present Friday 16.9. at the ICMC in Utrecht that presents an effect of test duration on ratings in perceptual listening tests found in two different datasets.

It would help to know more about your equipment, e.g., whether your microphone system has a probe tube on it. In essence you want to put the microphone at the position of the eardrum, which can be done with a probe tube and an anesthetized animal. Otherwise measure with the microphone at the position where the animal's eardrum(s) will be during the procedure. You also need to be sure that you are using a free-field calibrated microphone. If you change the setup you need to re-check the calibration. Make sure the space around the animal is free of hard, sound-reflecting surfaces or cover such things with soft cloth.

The hair cells in the inner ear transduce pressure waves into a neuro-chemical response that activates primary auditory nerve fibers. These fibers carry information from the inner ear and terminate in the brainstem auditory nuclei. There is a feedback loop from these nuclei back to the hair cells called the efferent system. 

Mario,

In the firing for shorter time periods, the rate varies stochastically, even if an auditory fibre is phase locked to a high degree (perfect phase locking is not observed, but vector strengths can be very high, meaning that the vast majority of intervals are locked to the phase of the stimulus). So it really is a question of what you mean by constant. The most exact spacing in time is only achieved during phase locking to high-level sounds at low frequencies – that is frequencies below the maximum firing rate of the fibre. Above that frequency, some of the cycles of the stimulus will be “missed”, i.e. the fibre will not be able to fire again that quickly. However, the spacing of the next firing will still be closely related to the phase (one, two, three cycles, etc). There is no minimum firing rate of auditory neurons in the cochlea – all of them have spontaneous activity that can be from below 1 spike/s up to about 100/s. During phase locking, such spontaneous firings become “locked” to the sound stimulus. The maximum firing rate of primary auditory neurons is somewhat higher than 300/second, pretty much irrespective of the best-response sound frequency. This maximum rate is not restricted to the auditory system but is true for all neurons of endothermic vertebrates. The longer the sound pulse, the more the rate will fall over time, often reaching a lower plateau rate after about 50 -100 ms (this is called adaptation). As I wrote before, it is likely that at low frequencies, the brain uses the spacing of the firings to derive the frequency of the sound (originally called the “volley theory”). Above frequencies where the spacing between firings no longer contains this information, i.e., above perhaps 1-2 kHz in humans (this is a guess), the information concerning the frequency of the sound is only conveyed by the place of origin of the fibres in the cochlea (tonotopic organization). What a firing neuron sounds like (the one in this video has a very variable rate and is not, I think, an auditory neuron) can be heard at:

I am not aware of a web site that offers a real sound recording of cochlear neurons firing, but some firing patterns are shown, for example in:

Geoff Manley

Are there any fMRI studies on KKS?

Dear Marcia,

Excellent question. I sense from your description and Epstein's that what you're after are words that have been specifically invented as abstract labels for auditory phenomena, (typified by such words as "dog, chair, cloud" that label visual phenomena) as opposed to ones that are obviously imitative of them (miaow, crunch, howl) or ones originally relating to physical acts of  producing them (bang, slam, yell, shout, cry etc).or to commands to attend to them (listen, hear). Indeed, I've always been struck by how few such words come to mind, at least in respect of describing the everyday world. One that does fit the above criterion is, of course, the word "sound" itself.

Regarding domain-specialized words, jargons, etc,, In Western music, basic invented abstract vocabularies exist for referring to pitches (eg sol-fa,) and adoptive abstract vocabularies using alphabetic and numeric labels, for referring to specific types of interval or chord (eg.dominant seventh, alternavely C7), which, for untrained persons, are as unevocative of auditory phenomena as are novel visually-referencing words and likewise have to be learned by deliberate association in order to imagine and identify the phenomena they refer to. More general in scope, chords are referred to as "dissonant", "consonant", or "euphonious",  conveying their affective status; these might be classified as bona fide inventions, being derivations of "sound" or its Greek counterpart. Timbre-denoting words typically make reference to instruments most strongly associated with producing a given timbral quality, but otherwise are metaphoric borrowings (grainy, smooth, harsh) mostly from the tactile language domain. To my knowledge, no words, invented or borrowed, exist for specifying the texture of  vertical spaced chords, for which a very large, dedicated vocabulary would obviously be required. Temporal descriptors, (e.g.quaver, minim, breve, longus as well as rhythm) are all borrowed terms not originally referring to sounds.

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For a cheap setup, for 2 by 2 cases, behringer ecm8000 measurement microphones, and any usb interface, in particular I have used an alesis io2 express 2 channel USB interface. You will need to adapt some stand to mount the microphones.

Use a notebook for recording, unplugged from the wall to avoid power noise. Get a good characterization of the room acoustic characteristics. You can measure impulse responses using TSP method or MLS method and then schroeder backintegration to estimate power decay curves. I have made some software for this, you can find it here: http://ldipersia.wikidot.com/software#revtime

If you have a sound proof room you can get better recordings. You can add drapery and carpets to reduce reverberation time, and you can use plywood panels to increase the reverberation time, so you can produce different environments to perform the experiments.

Interesting discussions: I have studied how hearing loss might contribute to subjective sound scopes, especially how HI persons describe their artificial hearing experiences. A challenge might be division to extrovert and introvert personalities also among HI persons. In Baderborn is arranged a seminar of audionarratology (use as search term). These studies might add some information of how people "hear" .

Change pitch perception by will? Yes! Try this: turn on a sinewave generator, then bite your teeth quite hard together. The loudness changes, and (likely due to that), the perceived pitch. You can also shake your head to create a nice pitch-vibrato (Doppler effect).

"The literature of both mystics and Near Death Experiences, is full of what are referred to as veridical hallucinations"

It seems likely that the basic cause of hallucinations is similar whether in mystics, NDE, normals or schizophrenics, so where is the evidence for veridical ones in the psychiatric literature? After all, every day psychiatrists see persons claiming veridical experiences.

Your guess is right: the preference for germanium can be regarded as this urban legend. Many audiophiles have a strong (almost religious) belief that germanium is better than silicium, tubes are better than semiconductors, etc. As has been said already, the BE voltage of germanium transistors is about 0.2 to 0.3 Volts whereas that of silicium is about 0.6 to 0.7 Volts. But that has not much to do with the cross over distortion of a power stage with transistors. What is crucial to this cross over distortion is the equality of the two halves of the power stage. Ironically, with silicium transistors it is much easier to reach a high level of equality compared with germanium. In addition, (as said already) silicium can stand a much higher temperature range so that cooling requires less precautions.

In modern power output stages dual complementary power mosfets are used which have almost exactly the same (complementary) properties and a smooth I/V characteristic. So in practice the problem of cross over doesn't exist anymore. Additionally, these mosfets can be made for high voltages and currents so that output stages for very high power and extremely low distortion (say, 0.01% for the full power range!) can be made quite easily.

For pre-amps the noise properties are important. Here germanium is greatly inferior to silicium. So no need for germanium in the audio field at all.

For tubes versus semi conductors the story is even more dramatic for a number of reasons. About the aspect of distortion: in case of semi conductors, when the power stage is driven too high, the signal clips abruptly, causing high odd-harmonics-distortion. Vacuum tubes produce a gradual increasing distortion, starting already far below maximum amplitude with high values. Easy to prefer semi conductors then I suppose.

The sound source produces, in this example, 1000 periods per second, no more, no less, independent of the medium. The medium can only have influence on the propagation speed and as a consequence the wavelength, which is only a part of the distance between source and ear, depends on the medium as well. At the receiver side the eardrum vibrates according to the water (or air) pressure vibrations. The time of one period remains constant 1 ms. If you would hear, for example, a higher tone, where would all these extra periods come from? Not from the source, not from some 'memory' in the medium and not from alterations of the distance between source and eardrum (as would be the case of the Doppler effect). The only things that are dependent of the medium are the delay (which is a constant and which doesn't alter the frequency) and the spatial perception (which is a reverberation effect and also doesn't influence the frequency). So from the eardrum vibrations to the auditory nerves at the basilar membrane everything remains the same (even the temperature remains constant, so even the wavelength within the auditory system will not be dependent of the medium outside the ear). The time of one period remains exactly 1 ms in all circumstances because nothing produces extra periods within a certain time interval and nothing 'eats' periods. The tone will be exactly 1000Hz, in air and in water. You can test it with an (underwater) speaker and microphone if you like.

Thanks you very much for your help

Interesting question, I've also wondered about this convention. Not sure there are any benefits either way as long as it's stated. We have done AV sync experiments on spatially moving stimuli and denoted +ve values as auditory leading.

In A-T / V-T experiments we reference against the tactile stimulus.

Ear disease may pre-dispose but it's not a prerequisite. Most healthy adults experience these sorts of phenomenon to some degree as youngsters...

Go out in the bush, (sorry- I'm an Aussie- go out in the woods or the forest or the jungle or the fields or the mountains or the desert or the scrub or them thar boondocks), BUT whatever natural environment you go out into, do it by yourself...

Sit.

Wait.

If you are all alone. after a while, you will hear murmuring voices in the constant white noise of emptyness, wind, flowing water, leaves rustling, waves, rain etc.

This is normal.

Your nervous systemn is a machine, built by boot-strapping adaptive mechanisms, perfectly evolved to detect signals amongst noise.

Our nervous systemns are over-responsive to potential signals, rather than under-responsive, largely because for the vast majority of our evolution, it has been adaptive to treat every rustle in the bushes as a potential ambush predator (think tigers. leopards. jaguars, lions) and counterproductive to ignore such noises, (even if 99% were false alarms).

When someone's "threat detectors" are over active, (as in psychosis or extreme situations) then even the background noise of an airconditioner quietly humming in the ceiling is actually a hub-bub of ranting voices.

As Anthony and Silvia have already stated, it's how people respond to these symptoms, not whether they experience them, that's important.

Silvia, I can't find the article you mentioned. Can you post a link?

Paul.

Dear Nicolas,

here are some suggestions for papers you could read: Stansfeld et al., Aircraft and road traffic noise and children's cognition and health: a cross-national study. The Lancet; 365:1942-49 (2005).

Clark et al. Exposure-effect relations between aircraft and road traffic noise exposure at school and reading-comprehension: the RANCH-project. AJE, 163(1): 27-37 (2006).

Van Kempen et al., Neurobehavioral effects of transportation noise in primary school-children: a cross-sectional study. Environmental Health 9(1): 5 (2010).

Researchers such as Staffan Hygge, Bridget Shield and Peter Lercher are also working in this field and wrote some interesting papers.

Hope this helps!