C - Moray Flashcards
Aim
- The first experiment in this study aimed to test Cherry’s findings more rigorously whilst the second and third experiments aimed to investigate other factors that can affect attention in dichotic listening.
Background
- Cherry’s (1953) method of ‘shadowing’ one of two dichotic messages for his study of attention in listening found participants who shadowed a message presented to one ear were ignorant of the content of a message simultaneously presented to the other ear.
- Other researchers then moved on from Cherry’s work on how people can attend to one message by investigating why so little seemed to be remembered about the other conversations (Hampton & Morris, 1996).
Method
- All tasks were laboratory-based, had high levels of control and had an IV and DV. Therefore they were all laboratory experiments.
- In all tasks, the apparatus used was a Brenell Mark IV stereophonic tape recorder modified with two amplifiers to give two independent outputs through attenuators, one output going to each of the earpieces of a pair of headphones. Matching for loudness was approximate, by asking participants to say when two messages that seemed equally loud to the experimenter were subjectively equal to them.
Experiment 1
This used a repeated measures design. This independent variables (IVs) were:
(i) the dichotic listening test
(ii) the recognition test
The dependent variable (DV) was: the number of words recognised correctly in the rejected message.
Experiment 2
This used a repeated measures design.
The independent variable (IV) was: whether or not instructions were prefixed by the participant’s own name. The dependent variable (DV) was: the number of affective instructions.
Experiment 3
This also used an independent measures design. The independent variables (IVs) were:
(i) whether digits were inserted into both messages or only one
(ii) whether participants had to answer questions about the shadowed message at the end of each passage or whether participants had to merely remember all the numbers s/he could.
The dependent variable (DV) was: the number of digits correctly reported.x
Sample
- Participants were undergraduates and research workers of both sexes.
- Participant numbers are not given for Experiment 1 but 12 participants took part in the experimental conditions in Experiment 2 and two groups of 14 participants were used in Experiment 3.
Procedure
- Before each experiment the participants were given four passages of prose to shadow for practice. All passages throughout the study were recorded by one male speaker.
Experiment 1 - A short list of simple words was repeatedly presented to one of the participant’s ears whilst they shadowed a prose message presented to the other ear. (The word list was faded in after shadowing had begun, and was equal in intensity to the shadowed message. At the end of the prose passage it was faded out so as to become inaudible as the prose finished.)
- The word list was repeated 35 times.
- The participant was then asked to report all he could of the content of the rejected message.
- S/he was then given a recognition test using similar material, present in neither the list nor the passage, as a control.
- The gap between the end of shadowing and the beginning of the recognition test was about 30 seconds.
Experiment 2 - This experiment was conducted to find out the limits of the efficiency of the attentional block.
- Participants shadowed ten short passages of light fiction.
- They were told that their responses would be recorded and that the object of the experiment was for them to try to score as few mistakes as possible.
- In some of the passages instructions were interpolated, but in two instances the participants were not warned of these.
- In half of the cases with instructions these were prefixed by the participant’s own name.
- Experiment 2 indicated that instructions might alter the set of instructions a participant in such a way as to alter the chances of material in the rejected message being perceived. Experiment 3 tested this point further.
- Two groups of 14 participants shadowed one of two simultaneous dichotic messages.
- In some of the messages digits were interpolated towards the end of the message. These were sometimes present in both messages, sometimes only in one. The position of the numbers in the message and relative to each other in the two messages were varied, and controls with no numbers were also used, randomly inserted.
- One group of participants was told that it would be asked questions about the content of the shadowed message at the end of each message, the other group was specifically instructed to remember all the numbers that it could.
Results
Experiment 1
Recognition scores for words from shadowed and rejected messages
- There was no trace of material from the rejected message being recognised.
- The difference between the new material and that from the shadowed message was significant at the 1 per cent. level.
* The 30-second delay was unlikely to have caused the rejected material to be lost because words from early in the shadowed message were recognised.
* These findings support those found by Cherry (1953).
Experiment 2
* Most participants ignored the instructions that were presented in the passages they were shadowing, and said they thought this was merely an attempt to distract them
- The mean number of instructions heard when presented in the rejected message was calculated, and the difference between the ‘names’ and ‘no names’ was significant: t = 3.05 (significant at greater than the 1 per cent. level, where t = 2.81.
- On only 4 out of the 20 occasions in which the ‘names’ instructions were heard did the participants actually make a change to the other message.
Experiment 3
* The difference between the mean number of digits reported under the two conditions of set were analysed and submitted to a t test. In none of the cases, whether the score was the mean number of digits spoken during shadowing, nor in the number reported, nor the sum of these two was the difference significant even at the 5% level of confidence.
Conclusions
- In a situation where a participant directs his attention to the reception of a message from one ear, and rejects a message from the other ear, almost none of the verbal content of the rejected message is able to penetrate the block set up.
- A short list of simple words presented as the rejected message shows no trace of being remembered even when presented many times.
- Subjectively ‘important’ messages, such as a person’s own name, can penetrate the block: thus a person will hear instructions if they are presented with their own name as part of the rejected message.
- While perhaps not impossible, it is very difficult to make ‘neutral’ material important enough to break through the block set up in dichotic shadowing.
Method Evaluation
The experimental conditions and the procedures that Moray created were highly controlled in a laboratory, therefore showing high internal validity. Lots of controls were used such as loudness of message matched to participant’s needs, messages recorded, spoken at a constant speed without expression in a male voice to ensure high internal validity.
However, due to the nature of the study and the sample, responses may have been a result of demand characteristics. Furthermore, listening to sounds through headphones and being asked to block out or shadow the noises is extremely artificial and not true to real life; therefore, the study lacks ecological validity. However the use of everyday materials and the individuals own name made the task a little realistic.
Data
Quantitative data was gathered in this study to allow comparisons between variables to be made for example the results showed that digits cannot be noticed even when they are expected.
Therefore it can be criticized for lacking qualitative data – Moray could have asked the P’s why they think they didn’t hear the message to check if it was demand characteristics that were causing the results
Ethics
Few ethical issues raised-practice sessions given to reduce potential stress caused by task given
Potential deception as P’s were told that they were being monitored in experiment 2 on their performance
Reliability
High use of controls and the procedures of the study, including instructions given to participants, are highly standardised which allows the study to be easily replicated and to check for the reliability of the findings.
However some differences in the participants experiences did arise, for example only some heard and responded to the instruction to change ears, so the passage intended to be the shadowed passage then became the rejected message.
Validity
s- high controls allowing cause and effect and no effect of volume, represents day to day of following one source of information while ignoring distractions, using own name increased validity
w- not realistic rarely continuously listen to repeat a message
Sampling Bias
As with many psychology studies, University students took part (as well as research workers). This sample is easily accessible, so saves time and money on obtaining participants.
However, the sample is not representative of everyone, as students and research workers are likely to have higher cognitive abilities and may perform better on attention tasks. Therefore the study lacks population validity.
Ethnocentrism
There could be differences in abilities to do dichotic listening tasks based on language capabilities and number of languages spoken, for example, people who are bilingual may be more competent at this sort of task with learnt skills in multiple languages.
