Chapter 2 Attention.
Auditory attention
Disentangling sounds.
Ears cannot avoid registering material like vision and uses differences in timing and intensity between different ears to indicate things like direction. Long wavelengths with a low pitch are used by our auditory system to find direction where intensity cues are only available for short wavelengths because of the shadowing effect created. (Reach both ears and not able to tell direction), this is because of our head size.
Natural sound contains both short and long wave lengths.
People with hearing impairment are unable to use inter-aural differences so find noise or echoing surroundings difficult.
Attending to sound.
(Attention is directed to either the direction of sounds or the pitch. Donald Broadbent’s theory in 1954 suggests that after early parallel processing we used serial processing to attend to sound.)
We are able to separate different sounds based on their source direction and give us the sensation of moving our listening attention also called spotlight of attention.
Donald Broadbent in 1952 used dichotic listening in research using headphones to show that if listing to a message in one ear and another in the other ear, nothing could be recalled from the unattended ear.
Broadbent further suggest that if the messages were short on both ears e.g. 3 words we could recall both sides, if longer than a few seconds the material would be lost. The store quality he termed echoic memory. He noted that we could recall male or female voices in unattended messages that could not be remembered. When alternating male and female voices were used the participant could use the pitch of voice to recall instead of location.
This made them believe that the brain process hearing serially (one thing at a time), even thou the earliest stages of processing happens in parallel (everything simultaneously).
Broadbent use this knowledge in the UK with pilots play radio signals in both ears to avoid interference from both ears called dichotic listening.
Naish in 1990 proved that giving a directional quality to sound like warning could improve response times.
Eavesdropping on the unattended message.
(Treisman in 1960 suggest words present to unattended ear can produce priming and will shadow a message from one ear to the other with little conscious awareness)
(Corteen and Wood 1972 us galvanic skin response (GSR) apparatus and the dichotic listening task to prove we attend to unattended messages by looking at the response to category.)
Treisman in 1960 suggest that we use an attenuation process that acts like a filter. For example the cocktail party effect when someone says our name.
Treisman use shadowing, a dichotic listening technique where participants speak out load what they would hear in one ear right after hearing it. When the story line was swapped between ears it showed that we then shadowed the other ear to follow the sense of the story. She called this priming, where participant’s temporary predicts the next word.
The lexical decision task requires participants to indicate if a string of letters spells a real word. It proves that people respond more quickly if the word relates to the preceding word.
Corteen and Wood in 1972 used mild electrical shocks to form associations to a particular category. The galvanic skin response (GSR) is used in lie detectors because they discovered a nervous person secrete salty fluid to lower resistance to an electric current.
Corteen and Wood used a GSR apparatus and used a dichotic listening task, they proved that even if the participant was not attending to a message or word that there was a response, even to words of the same category e.g. city. This strengthens the claim that meaning is perceived even if the participant is not consciously aware of it.
Norman in 1968 suggests that sufficient processing takes place of unattended information to activate relevant semantic memories e.g. meaning of words.
Visual attention
Hearing and seeing