The Classic Cocktail Party Phenomenon and Beyond - Essay Example

The ic Cocktail Party Phenomenon and Beyond One of the most fascinating properties of the human attentional system is its ability to pay attention to two things at the same time. This is demonstrated by everyday activities such as driving a car and, to some extent, studying for a test. The attentional system has two aspects which make these sorts of tasks possible. One aspect, called overt attention, occurs when an item of interest is selectively attended to in order to make some judgment about it (Driver 2001). In the process, an individual usually does learn and remember some things about the unattended stimulus, although they are not conscious of it. This is the result of covert attention (Driver 2001). The ability to attend selectively to auditory stimuli has been studied extensively using the dichotic listening technique (Driver 2001). Perhaps even more amazing than the ability to perform multiple tasks accurately is the ability to attend to one channel of auditory information while completely ignoring any other auditory information. In real-world situations, this is demonstrated at cocktail parties or restaurants, where different conversations are being carried on all around you, but you are able to selectively attend to one of them by filtering out all the others. At any given time, you can tune out the current conversation and attend to another one simply by switching the focus of your auditory attention. Cherry (1953) conducted one of the first studies to examine the recognition and discrimination of human speech when two spoken messages are presented simultaneously. Cherry (1953) found that subjects had no trouble paying attention to only one ear and repeating the message they heard in that ear. An interesting finding for the unattended ear (the rejected ear) was that subjects had little or no memory for the message in that ear. Even when the speech in the unattended ear was reversed, subjects could not identify what they were hearing, although some of them did notice something queer about it. Most of the information that was retained from the unattended ear dealt with the physical properties of the speech sound (whether the speaker was male or female, whether the voice was high- or low-pitched, etc.). No information about semantic content was retained (Cherry 1953). Wood and Cowan (1995) extended Cherry (1953)'s findings to gain a closer at what was occurring in the backward speech condition. It was believed that this condition would be near a threshold for detection, since it involves subtle physical changes and dramatic semantic changes. Further, they were interested in attention to the unattended channel before and after the switch to backward speech occurred. It was found that attention shifted to the unattended ear due to the fact that something different was happening to the irrelevant stimulus, rather than the change being found coincidentally due to periodic sampling of the irrelevant stimulus (Wood and Cowan 1995). This finding was true only for those subjects who were able to detect that a change occurred, whether or not they recognized it as backward speech. The authors fit their results within the framework of Treisman's attenuation theory. This theory explains that changes in the irrelevant stimuli will be noticed if they trigger a shift to the unattended ear (Driver 2001). This shift is dependent on the severity of the change in physical characteristics and also the preexisting level of activation of the units in memory that are excited by the stimuli occurring after the change. An interesting extension of the cocktail party effect to the visual modality was conducted by Shapiro, Caldwell, and Sorensen (1997). They used rapid serial visual presentation, in which the participant had to identify one or more targets. It has been consistently found that participants experience difficulty detecting the second target if it is within a certain temporal window after the first. This deficit in detection is called an attentional blink. It was found that participants do not experience an attentional blink for their own names, but they do for names of other people (Shapiro, Caldwell, and Sorensen 1997). The failure of the participants' own names to produce an attentional blink when presented first provides evidence for a late-selection filter theory (Driver 2001). To further assess the overt ability to selectively attend to a visual stimulus, even when there are distractors present, McSorley and Findlay (2003) measured individual's directed eye movements. Active search for targets in a visual search task, with items defined by their spatial frequency, was examined because past research has shown that spatial frequency often has an effect on visual attention (McSorley and Findlay 2003). The results showed that the more stimuli there are in a search task, the better performance is (McSorley and Findlay 2003). In a search task with a single distracting stimulus and a target stimulus, subjects were unable to successfully direct the eyes to the target if the distractor lay in between current fixation position and target location (McSorley and Findlay 2003). However, when the number of display items was increased to 16, then saccades were successfully directed to targets at all positions (McSorley and Findlay 2003). These results suggest that after a certain number of stimuli, the remote distractor effect may be extinguished (McSorley and Findlay 2003). Initiation time of a saccade has a strong affect on its accuracy (McSorley and Findlay 2003). This finding, using modern technology, has great implications for the study of selective attention. Another use of modern technology in the examination of selective attention can be found in Strayer and Kramer's (1990) research. In this experiment, event related potentials (ERPs) were used to measure subjects' dual task performance. Subjects performed consistent and varied mapping versions of a Sternberg memory search task, both separately and together with a recognition running-memory task (Strayer and Kramer 1990). In different conditions, subjects were told to focus on either the Sternberg or running memory tasks, or to emphasise the tasks equally. When the Sternberg task was paired with the running memory task, performance decrements were seen in the decrease in amplitude of the P300 component of the event-related brain potential (Strayer and Kramer 1990). The P300 is the brain wave largely associated with attentional processes (Strayer and Kramer 1990). All of the above experiments were conducted using adult participants. Very little research is available concerning children's selective attentional abilities, and almost no evidence exists concerning children and eye movements or ERPs. This leaves some important unanswered questions. When does the ability to selectively attend to stimuli begin Is it birth or early childhood Is the ability to discriminate between two or more sources of auditory or visual information innate, or is it learned through almost constant exposure to sights and sounds in the environment Looking at this effect with infants would enable researchers to answer this question more thoroughly. Also, examinations of this sort throughout the early childhood school years would provide a most interesting developmental perspective on this issue. In addition, assessing the developmental differences between older children and adults would be useful for gaining a more complete picture of the development of auditory and visual attention across the lifespan. The issues that have been raised in the literature concerning the cocktail party phenomenon, and other aspects of selective attention, regarding how much is remembered or noticed from the unattended stimulus are intriguing. Further, they are very practical concerns, since they deal with things that we come across everyday in our own lives and our own perceptions of the world. It is counter-intuitive to think that something you are not paying attention to can be encoded in your working memory, since attention and memory are inextricably linked; however, it is rather comforting to note that although your attention may be divided between multiple tasks or channels, you will still pick up more information than you realise. References Cherry, E.C. (1953). Some experiments on the recognition of speech, with one and two ears. Journal of the Acoustic Society of America, 25: 975-979. Driver, J. (2001). A selective review of selective attention research from the past century. British Journal of Psychology, 92: 53-70. McSorley, E. & Findlay, J. M. (2003). Saccade target selection in visual search: Accuracy improves when more distractors are present. Journal of Vision, 3(11), 877-892 Shapiro, K. L., Caldwell, J., & Sorensen, R. E., (1997). Personal names and the attentional blink: A visual cocktail party effect. Journal of Experimental Psychology: Human Perception and Performance, 23(2), 504-514. Strayer, D., & Kramer, A. F. (1990). Attentional requirements of automatic and controlled processing. Journal of Experimental Psychology: Learning, Memory, and Cognition, 16, 67-82. Wood, N., & Cowan, N. (1995). The cocktail party phenomenon revisited: Attention and memory in the classic selective listening procedure of Cherry (1953). Journal of Experimental Psychology: General, 124(3), 243-262. Read More