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Selective Auditory Attention
Attention is concerned with the concentration towards something, which has the potential to be able to narrow down the range of stimuli presented. However in auditory attention, the ears and auditory cortex are associated with it. Over the years, there has been increased research in the selectiveness of auditory attention, namely selective hearing.

Selective Hearing is a type of attention, selective attention to be specific. It involves the auditory system of the nervous system. Audition is one of the five essential senses humans need for carrying out the many daily activities. Without it, humans would not be able to enjoy the sounds and music of this world. Selective hearing is not a physiological disorder but rather it is the amazing capability of humans to block out sounds and noise. It is the notion of ignoring certain things in the surrounding environment.

Selective hearing does not involve the sounds that are not heard. However, it is characterized the action in which people focus their attention on a specific source of a sound or spoken words. The sounds and noise in the surrounding environment is heard by the auditory system but certain parts of the auditory information are processed in the brain only. Most often, auditory attention is directed at things people would like to hear. The increased instances of selective hearing can be seen in family homes. A common example would be a mother asking her child to do something before he or she can enjoy a reward. Mother may say: “James, you can have an ice-cream after you clear your room.” And James replies: “Thanks mom! I needed that ice-cream.”

Through observations, one would realize that it is the reward that is heard almost all the time. The mind does not process the auditory information about the chore. It is basically the filtration of positive pleasant information. If the child was not physically impaired in hearing, he would have heard the whole sentence being said. It has puzzled parents, as well as psychologists, at the way the child’s mind can selectively hear the things that they want to hear and leave out unpleasant tasks.

Function of the Auditory System
The auditory system consists of the outer ear, middle ear, inner ear and the auditory nerve and cortex, classified under the central auditory pathway. According to Bess and Humes (2008), the function of each respective area is as follows:

Outer Ear: The pinna and external auditory meatus are the main composition of the outer ear. Its function is to protect the middle and inner ear. The pinna of the outer ear helps to amplify and localize sound sources.

Middle Ear: The three smallest bones of the body, also known as the ossicles, are found in the middle ear. They are the malleus, incus, and stapes. This area of the auditory system compensates for the loss of sound energy when going from air to a fluid medium. It has the ability to amplify or boost sound depending on frequency.

Inner Ear: There are two important components in the inner ear, namely the cochlea and the vestibular system. The inner ear is implicated in the process of filtering and transducing auditory information. Mechanical energy is converted into electrical energy by the movement of hair cells in the cochlea.

Central Auditory Pathway: It is the pathway in which auditory information passes through the ear into the brain. It travels along the auditory nerve which leads to the auditory cortex. Once in the auditory cortex, the information is then processed.

History
Researchers have been studying the reasons and possibilities of this missing link in the procedure of the selectiveness of auditory information in the brain. In 1953, a cognitive scientist from England, Colin Cherry, was the first person to discover a phenomenon called the cocktail party problem. He suggested that the auditory system can filter sounds being heard. Cherry also mentioned that the physical characteristics of an auditory message were perceived but the message was not semantically processed. Another psychologist by the name of Albert Bregman came up with the Auditory scene analysis model. The model has three main characteristics, segmentation, integration, and segregation. Segmentation involves the division of auditory messages into segments of importance. The process of combining parts of an auditory message to form a whole is associated with Integration. Segregation is the separation of important auditory messages and the unwanted information in the brain. It is important to note that Bregman also makes a link back to the idea of perception. He states that it is essential for one to make a useful representation of the world from sensory inputs around us. Without perception, an individual will not recognize or have the knowledge of what is going on around them.

Recent Research
Recently, researchers have attempted to explain mechanisms implicated in selective auditory attention. In 2012, an assistant professor in residence of the Neurological Surgery and Physiology in the University of California San Francisco examined the selective cortical representation of attended speaker in multi-talker speech perception. Edward Chang and his colleague, Nima Mesgarani undertook a study that recruited 3 patients affected by severe epilepsy, who were undergoing treatment surgery. All patients were recorded to have normal hearing. The procedure of this study required the surgeons to place a thin sheet of electrodes under the skull on the outer surface of the cortex. The activity of electrodes was recorded in the auditory cortex. The patients were given two speech samples to listen to and they were told to distinguish the words spoken by the speakers. The speech samples were simultaneously played and different speech phrases were spoken by different speakers. Chang and Mesgarani found an increase in neural responses in the auditory cortex when the patients heard words from the target speaker. Chang went on to explain that the method of this experiment was well-conducted as it was able to observe the neural patterns that tells when the patient’s auditory attention shifted to the other speaker. This clearly shows the selectiveness of auditory attention in humans.

Prevalence
The prevalence of selective hearing has not been clearly researched yet. However, there are some that have argued that the proportion of selective hearing is particularly higher in males than females. Ida Zündorf, Hans-Otto Karnath and Jörg Lewald carried out a study in 2010 which investigated the advantages and abilities males have in the localization of auditory information. A sound localization task centred on the cocktail party effect was utilized in their study. The male and female participants had to try to pick out sounds from a specific source, on top of other competing sounds from other sources. The results showed that the males had a better performance overall. Female participants found it more difficult to locate target sounds in a multisource environment. Zündorf et al suggested that there may be sex differences in the attention processes that helped locate the target sound from a multisource auditory field.

Is it a disorder?
Selective hearing is not known to be a disorder of the physiological and psychological aspect. Under the World Health Organization (WHO), a hearing disorder happens when there is a complete loss of hearing in the ears. It means the loss of the ability to hear. Technically speaking, selective hearing is not “deafness” to a certain sound message. Rather, it is the selectiveness of an individual to attend audibly to a sound message. The whole sound message is physically heard by the ear but the astonishing idea is the capacity of the mind to systematically filter out unwanted information. Therefore, selective hearing should not be confused as a physiological hearing disorder.