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气的感觉是不同的。无论如何，如今看来它还能帮助你听懂某人说的是什么。这项发现或许或许能创造出一种能释放气息的助听器。

视觉能影响听觉，这大家都知道。例如，若我们听到有人说"吧",但看见那人说的是"嘎",我们就会觉得我们听到了"嗒".加拿大温哥华大英哥伦比亚大学的布莱恩吉克以及同事便猜测，触觉是否也会影响听觉。

讲话时， "pa"和"ta"这两个音节在发声吐字时人在呼气，而 "ba"和"da"时则没有。有时人在讲话时并不时常注意到这样的喘气，吉尔的研究组这样解释道：大脑可能发出命令让人喘气，从而调节某些声音的认知。

他们安排66位志愿者辨认一位男声发出的四音节的单词，不仅如此，他们加入背景音乐使其更有难度。同时，在到某些音节时，他们还加入一些喘息到受试者的手部或颈部。

尽管其中许多志愿者都没有有意识的感觉到这些喘息，他们在加入这些喘息之后辨认出"pa"和"ta" 的几率更大。相对的，加入喘息之后，他们没有很正确的辨认出"ba"和"da",而错误的认为它们是"pa"和"ta".

吉克说，我们时常凭喘息声来听清讲话。"它会在你脑中融合成一体，"他说道，当人们发现有发声的音节时，他们会想像有助听器或是脑中装有可以喘息的器械。像这样的，这会帮助飞行员勉强的在一架轰隆的飞机上进行对话，他这样阐述说。但是，纽约大学的约翰福克斯说道，这样的喘息不一定能用在现实情况中。