Concentrating On A Visual Task Can Leave You Momentarily Deaf!

09.12.2015, Earlier researchers had revealed that background noise is detrimental to tasks involving cognition, concentration and attention. And now, a new study that has been published in the Journal of Neuroscience suggested that focusing on a visual task can render you momentarily 'deaf' to sounds at normal levels.

According to a new University College London (UCL) study that has been funded by the Wellcome Trust, "The senses of hearing and vision share a limited neural resource."

While examining brain scans of 13 volunteers, the researchers revealed that the brain response to sound was significantly reduced found when the volunteers were engaged in a demanding visual task. Besides this, examination of people's ability to detect sounds during the visual demanding task also showed a higher rate of failures to detect sounds, even though the sounds were clearly audible and people did detect them when the visual task was easy.

Trying to discover cause and effect of concentrating on visual task, study co-author Dr Maria Chait (UCL Ear Institute) said, "We found that when volunteers were performing the demanding visual task, they were unable to hear sounds that they would normally hear."

Chait further added, "The brain scans showed that people were not only ignoring or filtering out the sounds, they were not actually hearing them in the first place."

By measuring brain activity in real-time using MEG (magnetoencephalography), this is the first time that researchers have been able to determine that the effects are driven by brain mechanisms at a very early stage of auditory processing. It would be expected to lead to the experience of being 'deaf' to these sounds, they added.

Co-author Nilli Lavie said, "Inattentional deafness is a common experience in everyday life, and now we know why."

Lavie, who is a professor of Psychology and Brain Sciences and Director of the Attention and Cognitive Control laboratory at the UCL's Institute of Cognitive Neuroscience, also gave an example by stating that, "If you try to talk to someone who is focusing on a book, game or television programme and don't receive a response, they aren't necessarily ignoring you, they might simply not hear you! This could also explain why you might not hear your train or bus stop being announced if you're concentrating on your phone, book or newspaper."

She further added, "Pedestrians engaging with their phone, for example texting while walking, are also prone to inattentional deafness. Loud sounds such as sirens and horns will be loud enough to get through, but quieter sounds like bicycle bells or car engines are likely to go unheard."