Donald Broadbent an ex-RAF fighter became a cognitive psychologist at a time when the cognitive approach was just beginning to gain momentum. Much of the psychology that was going on at the time was based around the practical implications of psychology, and cognitive psychology seemed to many as cut off from this and purely theoretical. Broadbent’s mentor at the University of Cambridge was Bartlett, who believed that most of the important theoretical discoveries that had been made were based on practical underpinnings and that real-world problems were often good starting points for understanding the mind. Broadbent was interested in accidents that had occurred frequently in the RAF when pilots had confused similar looking controls. He believed that if the way that the pilot’s minds worked was taken into consideration during the design process, then these sorts of accidents could be easily avoided. Because of this, Broadbent wanted to better understand the minds of the pilots and their capabilities.
Broadbent believed that mistakes were most often made when there was too much incoming data coming from several different sources at once. Broadbent had in particular noticed that air traffic control crew could only attend to one voice coming into their headset at a time. He wanted to understand why this was and how the mind selected which message to listen to. He then devised what has now become a famous experiment: the dichotic listening experiment. In this experimental model, the participants would be played two streams of audio at the same time, one in the left ear and one in the right ear. He would then test their ability to recall the information that had been presented. He quickly found that as was suspected, not all of the information could be recalled, since participants could only listen to one stream of information at a time. He suggested that if too much information was entering the brain at one time, one input channel of information would be blocked so as to focus on the other. This would enable just the central channel of focus to be understood properly.
Cherry went on to question this theory of dichotic listening, based on what he called the ‘cocktail party problem’. He was interested in how, if at a cocktail party, we manage to select which conversations, of the many that are going on, to listen to and which to ignore. He also wanted to know what factors could potentially cause us to be distracted from the conversation that we are trying to listen to. Broadbent showed with further experimentation that what we decide to listen to is based on the characteristics of the voice, since we are more likely to listen to a voice that is clearer and has a specific tone. However, Broadbent and Cherry also showed that when attempting to listen to a stream of information in just one ear, participants could do this and the information from the other ear could be effectively ignored. This meant that those in air traffic control could still not monitor both streams of information at once, but were able to focus on just one stream if they were told which one was most important, rather than allowing their brain to randomly assign them information based on irrelevant characteristics of the audio.
This finding is one that shows how useful psychology can be at solving real world problems. It is also an area that has had much further research, so if interested have a look online for further factors that affect which streams of information we process. This is an area that will undoubtedly be further researched and that we will see further implications from in the future, since so many situations are relatable to the need to select what is important from competing inputs of information.
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