Moray

• Attention has a selective nature
• Broadbent- too much information from world, humans have to choose to notice certain info- brain has limited capacity
• Early models of attention assumed serial processing where each operation is carried out step by step
• Kahneman- divided attention- serial processing
• Allport- multi channel attention- two or more operations can happen at once
• study two methods of attention

  • selective attention- two or more messages played + ppts respond to one- shadowing- one said after being heard
  • divided attention- ppts asked to respond to all of the messages
• Cherry- methods of shadowing two dichotic messages for study of attention found ppts who shadowed a message in one ear were ignorant of content in other
• Hampton + Morris- how people attend to one message by investigating why so little was remembered of other conversation
• AIM

  1. test previous findings more rigorously
  2. /3.- look at other factors that can affect attention in dichotic listening
• Lab experiment- high control- stereophonic tape recorder modified with two amps to give two independent outputs- one going into separate earphone- matching for loudness approximate- ppts asked when messages seemed equally loud
• Experiment 1- repeated measures

  IV- dichotic listening test and recognition test

  DV- number of words remembered correctly in rejected message
• Experiment 2- repeated measures

  IV- whether instructions were prefixed by ppts own name

  DV- number of affective instructions
• Experiment 3- Independent measures

  IV- whether digits were inserted into both messages or only one. Whether ppts had to answer questions about shadowed message or whether ppts had to recall all the numbers they could

  DV- number of digits correctly reported
• Sample: undergraduate students + research workers.

  Experiment 1: unknown

  Experiment 2- 12

  Experiment 3- 2 groups of 13
• Before the experiment ppts were given 4 passages of prose to study for practise- all passages from one male speaker
• Experiment 1- short list of words repeatedly presented in one ear whilst they shadowed a prose message presented to other- word list faded in after shadowing begun and faded out at the end- word list repeated 35 times

  ppt asked to repeat all they could of content of rejected message- then recognition test using similar material present used as control- gap between end of shadowing and recognition test was ab 30s
• Experiment 2- Conducted to find out limits of efficiency of attentional block- ppt was showed 10 short passages of fiction- told responses would be recorded + experiment was to get as few mistakes as possible - some passages had instructions that were interpolated but in 2 ppts warned- - half of cases instructions were prefixed with ppts name
• Experiment 2- passages read in steady monotone voice at 130 words per minute- ppts responses recorded and later analysed

  • indicated that instructions might alter the chances of material in the rejected message being perceived- Experiment 3 tested further
• Experiment 3- 2 groups of 14- shadowed one of two simultaneous dichotic messages- some had digits interpolated at the end of the message- sometimes in both or sometimes in one- position relative to each other in messages was varied + controls with no numbers randomly inserted

  -one group ppts told would be asked questions ab shadowed message at the end, other group just asked to remember all numbers they could
• Experiment 1: No trace of material from rejected message being recorded - difference between new+ shadowed material significant at 1%
• Experiment 1: 30s delay unlikely to cause rejected material to be lost as words from early shadowed message recognised
• Experiment 2: most ppts ignored instructions presented in passages being shadowed + thought it was just an attempt to distract them
• Experiment 2: should be 36 sets of instructions preceded by name but discrepancy due to 3 ppts who heard instructions + changed ear so second set of instructions became rejected message
• Experiment 2: mean number of instructions before vs after name significant

  -only 4 occasions in which 'name' instructions heard did ppts switch to other message
• Experiment 3: difference between mean number of digits reported under 2 conditions analysed + submitted to a T-Test- no cases had significant difference at 5%
• Concluded: in a situation when ppt directs attention to reception of a message in one ear rejects a message in the other + almost none of verbal content in rejected message can penetrate
• Concluded: short list of simple words presented as rejected message shows no trace of being remembered, even when presented many times
• Concluded: Subjectively 'important' messages- name- can get through
• Concluded: difficult to make 'neutral' material important enough to block in dichotic shadowing