To assess how different styles of face masks affected speech intelligibility in normal hearing listeners, researchers from Washington University in St. Louis put some of the most popular mask designs to the test.
Their research was published in the journal Cognitive Research: Principles and Implications.
The team, from the labs of Kristin Van Engen, PhD, assistant professor of psychological and brain sciences and of linguistics in Arts & Sciences, and Jonathan E. Peelle, PhD, associate professor of otolaryngology at the School of Medicine, found that cotton masks with filter inserts and masks with a transparent plastic panel were linked to/associated with the worst performance when it came to understanding what the wearer was saying.
While they were surprised that listeners did not do better with transparent masks, the authors pointed out that the clear panels hurt the audibility of the speech signal more than other mask materials and that the panels often fog up, making it difficult to see the talker’s mouth.
And “They’re super uncomfortable and wet. They’re pretty gross,” said Violet Brown, a PhD student in Van Engen’s lab and the paper’s first author.
Brown spoke from experience; as the person who recorded the stimuli for the experiment, she spent plenty of time wearing the transparent mask, as well as three others. As part of their experiment, she spoke to participants in four different mask styles: a surgical mask, a cloth mask with a filter, a cloth mask without a filter inserted, and a mask with a clear plastic insert.
She also spoke unmasked.
The researchers weren’t simply interested in showing that face masks affect speech intelligibility. “We already know it’s harder to understand speech when you’re wearing a mask,” that’s pretty self-evident, Van Engen said. “We’re exploring the extent to which different masks affect one’s ability to understand speech in background noise — both in terms of how many words you can recognize and in terms of how difficult the task feels.”