SMARTPHONES AND TABLETS CAN MAKE YOU DEAF

By concentrating with extreme focus on a visual object, the surrounding sounds may be switched off, as a recent study proves so well. For a brief moment, it is almost as if you are deaf to what is going on around you.

The UCL study had its results published in the Journal of Neuroscience. The sense of sight and sense of sound both had a a common neural source. 13 volunteers had their brain scans taken. The brain scans showed that when they were absorbed in visual stimuli, their auricular sense was considerably reduced. 

When the visual tasks were relatively easy to perform, the surrounding sounds were still heard. But when they required immense powers of concentration, then the background noise just seemed to melt into thin air for the subjects.

This was seen to be the case even though the background noises were not inaudible. They were shrill and noisy yet went unheard due to the extreme concentration. This was a lab study which took care to separate cause and effect. Thus it cannot be waved aside so easily. 

"This was an experimental lab study which is one of the ways that we can establish cause and effect. We found that when volunteers were performing the demanding visual task, they were unable to hear sounds that they would normally hear," explains study co-author Dr Maria Chait (UCL Ear Institute).

"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."

The brain scans actually showed a very weird phenomenon. And this was that though the volunteers did obviously hear the noises, they hardly paid any attention to them. So much so that they actually seemed not to have heard the background noises at all. This was very strange indeed.

Termed inattentional deafness, this phenomenon occurs when people fail to hear anything when they are busy elsewhere. And it has to be seen to be believed. But as they say the proof of the pudding lies in the eating. Nevertheless, this is the first time that scientific proof of this strange occurrence has been provided using magnetoencephalography.

"Inattentional deafness is a common experience in everyday life, and now we know why," says co-author Professor Nilli Lavie (UCL Institute of Cognitive Neuroscience) "For example, 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.

The process lies in the brain’s activities as they occur in real time. The auditory responses responsible for inattentional deafness date back to an early stage in the evolution of the brain’s neural mechanisms. The experience of being almost literally deaf is very real and almost freaky in its level of surrealism. Yet this experience is a common one in everyday life.

"This has more serious implications in situations such as the operating theatre, where a surgeon concentrating on their work might not hear the equipment beeping. It also applies to drivers concentrating on complex satnav directions as well as cyclists and motorists who are focusing intently on something such as an advert or even simply an interesting-looking passer-by," said Lavie.  

"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."

When we don’t receive a response from someone busy in looking at something, we know this as inattentional deafness. And the level of multitasking that a person can engage in is limited.Beyond a certain point the level of attention to other tasks besides the primary one tends to suffer. However, the dangers exist such as in a surgery room where the surgeon might not hear the sound of the equipment while he is concentrating on sewing up the sutures.