Saying words such as punt, tackle and kick produces a puff of air that helps the listener distinguish words with similar letter sounds, even though the puffs are so subtle that they go unnoticed. Bryan Gick and Donald Derrick of the University of British Columbia set out to determine if these puffs enhance auditory perception. They had 66 participants listen to recorded sounds while receiving light, imperceptible bursts of air from thin tubes placed either over their hand or neck or in their ear.

In some cases, puffs came with the appropriate sounds (“pa” and “ta”), at other times not (“ba” and “da”). Without any puffs, participants misheard “pa” for “ba” and “ta” for “da” 30 to 40 percent of the time. The accuracy improved 10 to 20 percent when heard with an accompanying air puff over the hand or neck. No improvement took place, however, when an air puff went into the ear, suggesting that the participants were not simply hearing the airflow.

The opposite effect occurred when the volunteers received a puff with the inappropriate sounds “ba” and “da”: the accuracy decreased by about 10 percent if the sounds came with puffs. The researchers described their work, which might lead to improved hearing aids, in the November 26 Nature (Scientific American is part of Nature Publishing Group).