The act of hearing is a group effort for the human body's organs, involving the ears, the eyes and also, according to the results of a new study, the skin.
In 1976 scientists discovered the importance of the eyes to our sense of hearing by demonstrating that the eyes could fool the ears in a peculiar phenomenon named the McGurk effect. When participants watched a video in which a person was saying "ga" but the audio was playing "ba," people thought they heard a completely different sound—"da." Now, by mixing audio with the tactile sense of airflow, researchers have found that our perception of certain sounds relies, in part, on being able to feel these sounds. The study was published November 26 in Nature.
Normally when we say words with the letters "p," "t" and "k," we produce a puff of air. This puff helps the listener distinguish words with these letters from those with the similar sounding "b," "d" and "g," respectively, even though the puff is so subtle that most of us do not even notice feeling it. "Unless you're a microphone manufacturer or a radio jockey or a phonetician, this isn't something that you're aware of," says Bryan Gick, an associate professor of linguistics at the University of British Columbia in Vancouver, and lead author of the study. Donald Derrick, a graduate student in the University's Department of Linguistics, is the other author on the study.
Gick and Derrick set out to determine if these puffs of air help us to perceive "p" and "t" sounds. The pair had 66 participants listen to sessions of recorded sounds through headphones. In one session, the participants heard a combination of "pa" and "ba," and, in the other, "ta" and "da."
The researchers also sent light bursts of air from thin tubes placed over participants' skin, over either their hand, neck or in their ear. The participants were blindfolded so they did not know where the tube was placed. In some cases, puffs were released with the appropriate sounds, "pa" and "ta," and in other cases, they coincided inappropriately with "ba" and "da." As Gick notes, the puffs were about half as forceful as what we would feel in a normal conversation, and most participants were not even aware of them over the course of the experiment.
The researchers found that if there was no air puff, participants misheard "pa" for "ba" and "ta" for "da" 30 to 40 percent of the time. The accuracy improved 10 to 20 percent when an air puff over the hand or neck accompanied "pa" and "ta." No improvement occurred, however, if an air puff was sent through the tube in the ear, suggesting that the participants were not simply hearing the airflow.
The opposite effect was observed when the participants received an air puff with the inappropriate sounds— "ba" and "da." While subjects correctly identified these sounds in about 80 percent of cases when played without the release of air, the accuracy decreased by about 10 percent if the sounds were accompanied by puffs of air.
"Largely, in English, the difference between 'pa' and 'ba' is this puff of air," Gick says.
The ability of the skin to contribute to hearing could be due to the fact that the largest organ in the body is covered in mechanoreceptors. Gick says that he has even found that air puffs sent to the ankle can help the listener comprehend those "p," "t" and "k" sounds. These receptors in skin cells, which are similar to the ones in the ears, respond to the pressure created by airflow.
In the real world, the cues available to a listener vary. Standing a foot or closer to someone speaking normally should produce tactile puffs, Gick says. However, if the conversation were taking place on a windy street, this sensory input would be destroyed. Although people can hear sounds in the absence of airflow, these sensory cues could make it easier to distinguish between two words, such as "tall" and "doll," especially if there is a lot of ambient noise.
The feel of sounds could be exploited in devices for groups such as the hearing impaired. Gick is in the early stages of exploring how to incorporate into hearing aids airflow-detecting sensors that would produce a synthetic puff to the side of the neck. Because the skin mechanoreceptors among the hearing impaired typically function normally, Gick says, this additional tactile stimulus could help the person wearing the device perceive sounds. A similar concept could aid pilots in their noisy work environments.
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Add CommentHere's one more. The spine.
Reply | Report Abuse | Link to thisWhen I have a jet of water on my spine, the jet is literally heard as it approaches the neck area from below.
This effect was first noticed in a spa with water jets.
If our perceptions are heightened by system redundancies in our bodies such as those suggested in this article, then there are probably many more that we haven't even begun to identify.
Reply | Report Abuse | Link to thisIn reality, everything counts, and nothing exists in isolation. It's not surprising, really, that correlative non-auditory sensations would be included by the brain when identifying pieces of communication. In fact, I would not be surprised if communication via the written word would have been impossible had we not evolved to include non-auditory information in our reception & interpretation of speech.
Reply | Report Abuse | Link to thisWhen your hair stands up on the back of your neck,maybe you are feeling the sound vibrations of something moving behind you,a predator perhapts, although today most people don't have animals stalking them day or night,it is something that in the past may have gave someone a chance to get away.
Reply | Report Abuse | Link to thisSo a person hard of hearing would do well to face the person speaking and be close enough to feel the puffs (as well as see their lips move). If i lose my hearing like my dad and grandad, i'll try to remember this.
Reply | Report Abuse | Link to thisThis should be compared to the argument that the nervous system utilizes mechanical waves to carry signal.
Reply | Report Abuse | Link to thisThis should be compared to the argument that our nervous systems use mechanical energy to carry signal. Perhaps when our body senses mechanical energy resonant with what we are hearing (or what our brain thinks it is hearing - all that matters is that there is activity for it to be resonant with) the sensation we get from our skin is interpreted by the brain as part of the auditory signal.
Reply | Report Abuse | Link to thisWe should also think about those times that we feel sound, for example, laying in bed when a door opens or closes - I know I feel that mechanical energy transfer through my entire body. Also, when I was a child I was oblivious to the vibration of sound against my skin, now I even notice it with tiny sounds and quiet voices. So for me, knowing that we hear with our skin is just a matter of experience - especially considering that the ear is virtually just a refinement of the sense of touch.
Audiophiles (those who give a crap about the quality of recorded music) have claimed for generations that the accurate reproduction of signals beyond the technical range of the eardrum's response capabilities were important to the sensation of realism in musical systems. They argue that we shouldn't be compressing the data in our music but rather using the new technology to expand it if we wish to truly appreciate music in our homes. This study adds scientific evidence to their experience.
Reply | Report Abuse | Link to thisPerhaps this would help to explain the 'aura' pyhcics 'see' surrounding a person and can tell illness,temperament, state of anxiety etc.
Reply | Report Abuse | Link to thisThis phenomenon works in reverse as well. When I first put in my hearing aids in the morning, I viscerally feel and smell a breath of fresh air. I attribute this illusion to the fact that I am hearing the air moving around me.
Reply | Report Abuse | Link to thisOne more "redundant" piece of evidence for the primacy of auditory (ie receptive, signal effects via your ears and now your skin) comprehension of language over articulatory (ie productive, in your mouth) factors.
Reply | Report Abuse | Link to thisExcellent. I answered a finals exam question about this conflict some 40 years ago. Auditory primacy was clear even then. This finding makes the richness and power of our communications arsenal even more impressive.
Thanks Brian G and Donald D!
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Reply | Report Abuse | Link to thisHi everybody!! Now i know i am not the only one with a problem like mine. I've never made any trips back to Africa since past 3 years i left my country.I have a valid A - DIRECT AIRSIDE TRANSIT VISA from United Kingdom to my country issued in New York but no money for plane ticket. I have a plan to go to my country to submit my old passport and get a new passport even to visit my Dad and my family members and come back. I pray to God that there is someone out there that will be able to help me, please contact me (prof4real2005 AT yahoo DOT com)to take my information that you can use to buy me a plane ticket. THANKS. MAY GOD BLESS YOU ALWAYS. prof4real2005@yahoo.com
Reply | Report Abuse | Link to thisAllah hath (now) revealed the fairest of statements, a Scripture consistent, (wherein promises of reward are) paired (with threats of punishment), whereat doth creep the flesh of those who fear their Lord, so that their flesh and their hearts soften to Allah's reminder. Such is Allah's guidance, wherewith He guideth whom He will. And him whom Allah sendeth astray, for him there is no guide. (23) AZumor(39:23) Noble Quran
Reply | Report Abuse | Link to thisAllah hath (now) revealed the fairest of statements, a Scripture consistent, (wherein promises of reward are) paired (with threats of punishment), whereat doth creep the flesh of those who fear their Lord, so that their flesh and their hearts soften to Allah's reminder. Such is Allah's guidance, wherewith He guideth whom He will. And him whom Allah sendeth astray, for him there is no guide. (39:23) Quran
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