lets talk abt divided attention

DUAL-TASK PERFORMANCE
The study of divided attention has concentrated mainly on dual-task studies, in which participants' ability to perform two tasks together are studied under various conditions. Such studies have found three main factors, which affect dual-task performance:
Task similarity.
Practice.
Task difficulty.
Task similarity
Several studies have found that task similarity is an important factor determining our ability to perform two tasks at the same time. Researchers such as McLeod (1977; see PIP p.203) and Treisman and Davies (1973; see PIP p.203) have found that dual-task performance is greatly improved when the two tasks are dissimilar (e.g., in different sensory modalities).
However, while task similarity is relatively easy to measure and manipulate in a laboratory environment, it is much harder to measure the similarity of more everyday tasks, such as driving or playing the piano, for example.
RESEARCH ACTIVITY: Doing two things at once
Practice
Practice is another factor determining dual-task performance. Researchers such as Spelke et al. (1976; see PIP p.204) have found that, with practice, participants can greatly improve their dual-task performance (e.g., dictation and reading for comprehension).
They even go so far as to suggest that with practice, we can perform two tasks together equally well. However, this claim has been challenged and further studies have shown that although practice can increase dual-task performance, performance is not as good as when each task is performed alone.
Task difficulty
The third main factor determining dual-task performance is task difficulty. Researchers such as Sullivan (1976; see PIP p.204) and Duncan (1979; see PIP p.204) have found that increasing the difficulty of the tasks reduces performance and vice versa.
However, as with task similarity, it is very difficult to define task difficulty, particularly with everyday tasks.
In summary, research suggests that two dissimilar, highly practised and simple tasks can be performed well together, whereas two similar, novel and complex tasks cannot.
THEORETICAL ACCOUNTS
Several theories have been proposed to account for the findings of dual-task studies, some of which favour the concept of a limited capacity central processor and some of which argue that there are several specific processing resources.
Central capacity theories
Such theories account for the findings of dual-task studies by arguing that there is some central capacity or resources, which can be used flexibly across numerous activities, but which has limited resources. A further assumption central capacity theories make is that the ability to perform two tasks together depends on the demand for these on resources (see PIP p.205).
Interactive exercise: A capacity model for attentionTo view this feature you will need the Macromedia Flash plug-in. You can download this free from the Macromedia Download website.
An example of a central capacity theory is that of Kahneman (1973; see PIP p.206), who made four further assumptions regarding arousal; the greater the level of arousal, the greater the resources or capacity available.
Support for such theories comes from a study by Bourke et al. (1996; see PIP p.205) who gave their participants four very different tasks and then measured the degree to which each one interfered with the others. They found that these tasks did interfere with each other; the random generation task interfering to the greatest extent and the tone task interfering the least. These findings support the prediction of Kahneman's theory that dual-task performance should depend on the demands of each task on the total available capacity.
However, other studies have found less support for central capacity theories. For example, Hegarty et al. (2000; see PIP p.206) have found evidence that factors other than demands on central capacity are important in determining dual-task performance.
There has been greater support, however, for the two other predictions made by Kahneman's central capacity theory (see PIP p.207):
That there will be an increase in effort as task demands increase.
The amount of spare processing decreases as primary task demands increase.
Evaluation of central capacity theories
There is evidence in support of the key assumption that task difficulty helps to predict dual-task performance (Bourke et al., 1996; see PIP p.207).
There is evidence in support of Kahneman's assumption that the available processing capacity varies as a function of effort expenditure.
Many of Kahneman's key terms are not clearly defined.
Central capacity theory cannot account for the effects of task similarity on dual-task performance.
Central capacity theories have been accused of being descriptive rather than explanatory.
Bottleneck theory
An alternative explanation of the findings of dual-task studies is that there is a bottleneck in processing, which makes it hard for two decisions about the appropriate responses to two different stimuli to be made at the same time. This theory is supported by evidence from studies of the psychological refractory period effect (see PIP p.208).
However, evidence from studies by Schumacher et al. (2001; see PIP p.208) show that this processing bottleneck may disappear when well-practised participants perform simple tasks.
Evaluation of bottleneck theory
Evidence from numerous studies support the existence of a processing bottleneck, suggesting that at least some central processing is serial in nature.
Studies of the psychological refractory period effect provide precise assessment of the time taken to process stimuli in dual-task conditions.
The magnitude of the psychological refractory period effect is typically small, suggesting that many of the processes involved in dual-task performance occur in parallel.
There is evidence to suggest that there is not always a processing bottleneck in dual-task performance (Schumacher et al., 2001; see PIP p.208).
Multiple resources
Wickens (1984, 1992; see PIP p.208) provides a further alternative explanation for the findings of dual-task studies. He argues that people possess multiple resources and proposes that there are three successive stages of processing:
Encoding.
Central processing.
Responding.
Wickens' model makes two key assumptions:
There are several pools of resources.
If two tasks make use of the different pools of resources, then people should be able to perform both tasks without disruption.
Many of the findings from dual-task studies can be accounted for by Wickens' model, e.g., similarity of modality and similarity of response (see PIP p.209). However, it cannot account for interference between two tasks requiring different pools of resources.
Evaluation of multiple resources
There is reasonable evidence for the existence of multiple resources.
There is support for the notion that the amount of dual-task interference depends on the extent to which two tasks share common processing resources.
The model does not consider modalities other than visual and auditory inputs.
There is evidence of dual-task interference even when two tasks make use of different pools of resources (e.g., Bourke et al., 1996; see PIP p.209).
The model minimises the problems associated with the higher-level processes of co-ordinating and organising the demands of different tasks (Duncan, 1979; see PIP p.209).
SO WHAT DOES THIS MEAN?
The findings of dual-task studies indicate that task similarity, practice, and task difficulty are important factors in determining dual-task performance. Typically, dissimilar, well-practised, simple tasks can be performed together well, whereas similar, novel, complex tasks cannot. Several theoretical accounts have been proposed to explain these findings, such as central capacity theories, bottleneck theory, and multiple resources. Each of these approaches has received support from experimental studies and so it may be that a better approach would be to combine elements of each of the theories. For example, the processing system may have a hierarchical structure with a central processor at the top, with more specific pools of resources lower down.

Introduction

hi this is Iman and shriya who have created this blog for an assignment...... but later i ( iman) will be using this same blog so bettre remember this or else.....
we chose this name fairyland coz we love kids and also cuz we both act like kids ourselves. with all the temper tantrums and dadagiri...... we rule over others like the villains do in the fairytales... we can manaao any1 so bettre be careful and dnt take panga with us..............
njoy our bloggers land!!!!!!!!!!!!!!!