Smartphones, tablets, all other visually demanding gadgets can make you deaf

A new study in the United Kingdom revealed that concentrating and placing undivided attention into a visual task can make a person temporarily deaf to sounds coming from their environment.

Researchers at the University College London have found that the brain’s senses of vision and hearing share a limited processing capacity, so the brain is often forced to choose between them.

As the visual tasks in the study grew more demanding, the scientists found that the participants’ early response to sound was delayed a great deal.

This is not the first time that this phenomenon of “inattentional deafness”, where we fail to notice sounds when concentrating on other things, has been observed by scientists. They measured the brain activity in real-time using MEG (magnetoencephalography).

Professor Nilli Lavie, from the University College of London, the co-author of the study says that deafness due to inattention is a common occurrence in daily life, and we now know the cause. Motorists intently focused on an advert or an interesting passerby or drivers focused on complex directions are among other examples.

When we concentrate on a visual task, we become deaf to sounds we would normally be able to hear, a study shows.

The researchers recruited 14 people into the study and tasked them into trying to focus on a number of visual tasks while music played in the background.

Lavie said sounds such as horns and sirens are loud enough to be detected, but sounds such as vehicle engines and bicycle bells are more silent and are most unlikely to be heard.

“When the task was easier we could see a brain signal indicating they could hear the tone”, Lavie says. Don’t worry, you have not been ignored – he probably just didn’t hear you talking.

“Shouting might help”, she said.

While there is very little anyone can do to boost attention to visual tasks and sound at the same level of intensity, people in certain careers need to exercise extra caution while working so that the attention put into visual needs does not deaden them totally to audio cues. The researchers believe the participants were not just ignoring the sounds; they actually did not hear them. By giving participants two puzzles to complete – one complicated, one easy – they could tell focusing on a hard task minimised brain responses. “If our brain doesn’t respond because our attention is fully taken by another task, then we experience deafness”.

Now, by using brain imaging, researchers have uncovered the extent of this “inattentional deafness”, or how intensive visuals rob us of the ability to hear.