Moray (1959)

Attention in Dichotic Listening: Affective Cues and the Influence of Instructions

Background and aim: Research uses two main methods to study auditory attention:

Selective attention is tested by presenting two or more ‘messages’ at the same time and participants are instructed to process and respond to only one of them. The most popular way of doing this is to use shadowing, in which one message is fed into one ear and a different message into the other. Messages are repeated aloud as they are heard. This is known as dichotic listening and was first investigated by Cherry (1953) when researching the cocktail party phenomenon. Cherry found that those who ‘shadowed’ a message in one ear, were unaware of the content of the message in the other ear. Divided attention is tested using a dual-task technique, whereby participants must attend to two or more messages, which rather than focusing attention, deliberately divides it. The first experiment in this study aimed to test Cherry’s findings more rigorously, while experiments 2 and 3 aimed to investigate other factors that can affect attention in dichotic listening

Method: A tape recorder was used in this lab experiment, which was modified with two amplifiers to allow two outputs, one to each ear through a set of headphones. The messages were of equal loudness, judged by each participant. 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 used a repeated measures design and the IVs were a dichotic listening test and a recognition test, while the DV was the number of words recognised correctly in the rejected message. Experiment 2 used an independent measures design, for which the IV was whether or not instructions were prefixed by the participant’s own name, while the DV was the number of affective instructions. Experiment 3 used an independent measures design and the IVs were whether digits were inserted into one or two messages and secondly whether participants had to answer questions about the shadowed message at the end of each passage or just remember the numbers. The DV was the number of digits correctly recalled. All participants were undergraduates or research workers and were male and female. 12 people participated in the experimental conditions in Experiment 2 and two groups of 14 participants took part in Experiment 3. It is not known how many were in Experiment 1.

In 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 list faded in and out); the list was repeated 35 times. The participant was then asked to recall the content of the rejected message. About 30 seconds later they were given a recognition test using similar material, present in neither the list nor the passage, as a control.

Experiment 2 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 they should try to and make as few mistakes as possible. Rejected messages were played in the other ear which were not attended to, Moray wanted to find out of these messages would be heard if it included their name. The order of presentation of the rejected messages was as follows (instructions at the start of the passage/ instruction within the passage):

1 Listen to your right ear/ All right, you may stop now. 2 Listen to your right ear/ No instructions. 3 Listen to your right ear/ John Smith, you may stop now. 4 Listen to your right ear/ No instructions. 5 Listen to your right ear/Change to your other ear. 6 Listen to your right ear/ No instruction. 7 Listen to your right ear/ John Smith, change to you other ear. 8 Listen to your right ear - you will receive instructions to change ears/Change to your other ear. 9 Listen to your right ear/ No instructions. 10 Listen to your right ear - you will receive instructions to change ears/ John Smith, change to you other ear.

The passages were read in a steady monotone voice at about 130 words per minute and participants’ responses were tape-recorded and later analysed.

In experiment 3, participants were required to shadow one of two simultaneous dichotic messages. In some of the messages digits were added towards the end of the message either in both messages, or in one. The position of the numbers in the message and whether they were relative to each other in the two messages varied; controls with no numbers were also randomly inserted. One group was told they’d be asked questions about the content of the shadowed message at the end. The other group had to remember as many numbers as they could.

Results: Experiment 1 - The mean number of words recognised (out of 7):

Shadowed message- 4.9, Rejected message- 1.9, Similar words from either - 2.6.

There was no trace of material from the rejected message being recognised. The difference between the new material and the shadowed message material was significant. The 30-second delay was unlikely to have caused forgetting, because words from early in the shadowed message were recognised.

Experiment 2 - Most participants ignored the instructions that were presented in the passages they were shadowing and thought this was an attempt to distract them. In the

Affective (instructions preceded by name) condition 20 out of 39 messages were heard, while in the Non-Affective (instructions not preceded by name) condition only 4 out of 36 messages were heard. (3 results were rejected as participants started paying attention to the rejected messages). The results were highly significant.

Experiment 3 - After statistical analysis, it was found that there were no significant results between the two groups.

Conclusion: When we direct our attention to a message from one ear and reject a message from the other ear, almost none of the verbal content of the rejected message is able to get through this block. The short list of simple words which were presented as the rejected message could not be remembered even when presented many times. However, ‘important’ messages, such as our own name can penetrate this block, which may be part of the rejected message. It can be concluded that it is almost impossible to make ‘neutral’ material important enough to break through the block which occurs in dichotic shadowing.

Evaluation

Research method: The experimental conditions and the procedures that Moray created were highly controlled in a laboratory, therefore showing 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.

Reliability: 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.

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.