DEPENDING on whose it is, breath on your neck may or may not feel good. Either way, now it seems that it can help you understand what someone is saying. The discovery could lead to hearing aids that emit puffs of air.

    We know that what we see affects what we hear. For example, if we hear "ba" while watching a person saying "ga" we think we've heard "da". Bryan Gick and colleagues at the University of British Columbia in Vancouver, Canada, wondered whether tactile sensations affect hearing too.

    In speech, the "aspirated" syllables "pa" and "ta" are accompanied by a puff of exhaled air, whereas "ba" and "da" are not. Such puffs aren't always detected when someone is speaking, but Gick's team reasoned that the brain might learn to use puffs to modify its perception of certain sounds.

    They had 66 volunteers listen to a male voice saying all four syllables against background noise that made it hard to distinguish them. At the same time as some of the syllables, they delivered a puff of air to the hand or neck.

    Although many volunteers could not consciously feel the puffs, they were still more successful at correctly identifying "pa" and "ta" when these sounds were accompanied by air puffs. In contrast, air puffs made it less likely that they would correctly identify "ba" and "da" and more likely that they would mistake these for sounds for "pa" and "ta" （Nature, DOI: 10.1038/nature08572）.

    Gick says that we likely use puffs of air to make sense of speech. "It gets integrated into a single event in your mind," he says. He envisions hearing aids or headsets fitted with devices that emit puffs of air when they detect an aspirated sound. These might help pilots struggling to make out communications in a noisy plane, he says. But John Foxe at the City University of New York says it is not clear that puffs would work "in real-world conditions".

    不同的人呼在脖子上的氣的感覺是不同的。無論如何，如今看來它還能幫助你聽懂某人說的是什么。這項發現或許或許能創造出一種能釋放氣息的助聽器。

    視覺能影響聽覺，這大家都知道。例如，若我們聽到有人說"吧",但看見那人說的是"嘎",我們就會覺得我們聽到了"嗒".加拿大溫哥華大英哥倫比亞大學的布萊恩吉克以及同事便猜測，觸覺是否也會影響聽覺。

    講話時， "pa"和"ta"這兩個音節在發聲吐字時人在呼氣，而 "ba"和"da"時則沒有。有時人在講話時并不時常注意到這樣的喘氣，吉爾的研究組這樣解釋道：大腦可能發出命令讓人喘氣，從而調節某些聲音的認知。

    他們安排66位志愿者辨認一位男聲發出的四音節的單詞，不僅如此，他們加入背景音樂使其更有難度。同時，在到某些音節時，他們還加入一些喘息到受試者的手部或頸部。

    盡管其中許多志愿者都沒有有意識的感覺到這些喘息，他們在加入這些喘息之后辨認出"pa"和"ta" 的幾率更大。相對的，加入喘息之后，他們沒有很正確的辨認出"ba"和"da",而錯誤的認為它們是"pa"和"ta".

    吉克說，我們時常憑喘息聲來聽清講話。"它會在你腦中融合成一體，"他說道，當人們發現有發聲的音節時，他們會想像有助聽器或是腦中裝有可以喘息的器械。像這樣的，這會幫助飛行員勉強的在一架轟隆的飛機上進行對話，他這樣闡述說。但是，紐約大學的約翰福克斯說道，這樣的喘息不一定能用在現實情況中。