Reading always interferes with hearing Guilt is limited brain capacity

"Deafness due to inattention" widespread
Many people know the problem, you sit in the train and read in the newspaper. Suddenly we realize that we have already driven through our destination station and have missed our exit option. Frequently those concerned after such an incident, as it may have been possible that we have not heard the announcement of the train attendant. As everybody knows, this one always says every station, but why did not we hear it??
Such a thing is not really unusual, British researchers now found in a study. The problem, according to the medical profession, is our human brain. This has limited capacity and is unable to process both senses at the same time. The results of the study published the British scientists in the journal "Journal of Neuroscience".

Reading disturbs listening. Image: Eugenio Marongiu - fotolia

When we use two senses simultaneously, such as seeing and hearing, it is possible that these senses use the same neural resources. If then reading requires many resources, the other affected sense, in this case the hearing, is suppressed and possibly not evaluated.

Magnetic Encephalography: Scans bring new results
The scientists from University College London have now conducted a study on this topic. For this purpose, subjects were asked to solve various tasks on a screen. Subjects should identify specific letters. These had been mixed into another group of letters. The subject had to pick out the right letters. Some of the experiments were fairly easy, but there were also tasks that were heavier and required much more concentration, the researchers said in the study. When the subjects performed their tasks, the physicians played notes to the subjects. Throughout the period of the experiments, Katharine Molloy's research team scanned brain activity by magnetoencephalography.

Visual stimuli can suppress sounds in the neural processing chain
By evaluating the experiments it became clear that the subjects did not simply ignore the noise. The test subjects had not even been able to hear the sounds, explained the researcher Maria Chait. When people focus heavily on visual stimuli, co-occurring sounds are suppressed early in the neural processing chain. This was also clear, because at such moments the responsible brain areas would only have a reduced activity, the researchers added. When brain activity occurred shortly thereafter, it usually indicated a sensory perception. Subjects who concentrated very heavily; had a significantly reduced perception. These results made it clear that the noise never arrived in the consciousness of the subject.

"Deafness due to inattention" particularly dangerous in traffic
So-called "deafness due to inattentiveness" is an experience that every person has already experienced in everyday life. But now it is clear why the phenomenon occurs, Nilli Lavie said the co-author of the study. The results can now finally explain why, for example, we do not hear the announcement to our stop on the bus when we read a book or are too focused on our telephone. This inattention can also have serious consequences. For example, if surgeons miss auditory warnings from monitors during an operation, it will have dire consequences. Similar problems can also occur in people who as drivers focus too much on confusing instructions of the navigation device. In such cases, it often happens that important traffic noise is not noticed and processed at all.

Subjects overlook gorilla in older study
Earlier studies had shown that people in brain overload can not handle some sensory stimuli. If our brain is overwhelmed, it no longer works reliably, the processing of the stimuli of our senses is then severely limited. A well-known example of the so-called "inattentive blindness" is the "gorilla-in-our-center" study. In this study, scientists from Harvard University, in 1999, proved that subjects can even miss a human in the gorilla costume when they are distracted and focus heavily on other things. (As)