One of the earliest studies of focused attention involved the cocktail-party phenomenon (focusing on one conversation whilst ignoring others). Cherry (1953) investigated it using the dichotic listening task:
Method: Participants listened to a different message in each ear at the same time whilst shadowing (repeating) one of the messages.
The diagram below shows Cherry's method:
Results: Little or nothing of the unattended message could be recalled.
Conclusion: Attention can be focused on one stimulus and most other information is blocked.
Support for Cherry's work comes from Moray (1959). Seven words were repeated 35 times in the unattended ear, but subsequent recall was no better than chance.
However, Cherry found that some features of information presented to the unattended ear seem to get through the block, such as a change from a male to female or loud to quiet voice (physical features). The sound of your name (meaningful or semantic information) may also 'grab' your attention.
Broadbent (1954) used the split-span procedure to investigate focused attention:
Method: Three digits presented to one ear, whilst three different digits were presented to the other ear. Participants had to write down as many digits as they could remember. This was done in one of two ways:
The diagrams below show Broadbent's split-span procedure:
Results: Accuracy was better for ear-by-ear recall than pair-by-pair recall. Given the choice, participants preferred ear-by-ear recall.
Conclusion: Attention can only be focused on one 'channel' of information at a time and switching 'channels' is difficult.
Broadbent (1954) thought that we select one 'channel' of information for attention, for example the left or right ear, based on physical characteristics of the information. This means that information is not processed semantically (for meaning) until after it has been selected for attention. This is an early selection model.
Broadbent's model encouraged others to investigate the area of focused attention and is supported by evidence from the dichotic listening task and split-span procedure. However, it has a number of significant weaknesses:
- Information can be processed for meaning before selection (e.g. sound of your name grabs your attention).
- Attention can be switched easily from one channel to another (Gray & Wedderburn, 1960). The following pictures show the possible responses to Gray & Wedderburn's task, which do you think was most easy for participants?
A 'category-by-category' response was easiest for the participants, showing that it is possible to switch between different channels.
Treisman's (1964) model found solutions to Broadbent's problems. It is also an early selection model based on physical characteristics of the information. However, Treisman's filter attenuates (weakens), rather than eliminates, the unattended information.
A second filter processes the information for meaning, which may result in an attenuated channel being selected if it is important, for example: your name or an alarm call like 'help' or, to use Treisman's term, reaches the threshold level of intensity.
Treisman's model is supported by the work of Gray & Wedderburn (1960), which showed that channels could be switched easily to produce more meaningful information. Her own work, using speech shadowing, showed that an unattended message can be incorporated into the attended message if it makes more sense (Treisman, 1960):
Critics of Treisman's model think that it is too complicated and does not explain how the process of attenuation occurs.
The Deutsch & Deutsch (1963) model is called a late selection model because they claim that all information (attended and unattended) is analysed for meaning in order to select an input for full awareness. Whether or not information is selected is dependent on how relevant it is at the time.
The same evidence supporting Treisman's model supports this theory. However, the Deutsch & Deutsch model explains the process of focused attention more simply. More support comes from Moray (1969), who paired electric shocks with a word to condition a galvanic skin response (GSR) when the word was spoken. A GSR was produced even when the word was presented to the unattended ear and the participants were unaware of it.
Further evidence for the late selection model is that unattended messages can influence participant's understanding of the meaning of ambiguous sentences (MacKay, 1973):
It seems unlikely that all information should be processed semantically before we are made aware of it. This suggestion is backed up by evidence that we are better at spotting key words in attended messages than unattended messages - according to Deutsch & Deutsch we should be equally as good at each.
In this Learn-it, you have reviewed the research studies and models into focused attention. Here's a little test to see how much you remembered: