Span of Attention span of attention varies within the limit of seven plus or minus two. This is popularly known as the “magic number”. It means that at a time, people can attend to a set of five to seven numbers, which can be extended to nine or more under exceptional conditions. That is perhaps the reason why motorbikes or cars are given a number plate that contains only four digit numbers with some alphabets.
In case of violation of driving rules a traffic police can easily read and note these numbers along with the alphabets. refers to our ability to maintain attention on an object or event for longer durations. It is also known as “vigilance”. Sometimes people have to concentrate on a particular task for many hours.
Air traffic controllers and radar readers provide us with good examples of this phenomenon. They have to constantly watch and monitor signals on screens. The occurrence of signals in such situations is usually unpredictable, and errors in detecting signals may be fatal. Hence, a great deal of vigilance is required in those situations.
Factors Influencing Sustained Attention Several factors can facilitate or inhibit an individual’s performance on tasks of sustained attention. Sensory modality is one of them. Performance is found to be superior when the stimuli (called signals) are auditory than when they are visual. Clarity of stimuli is another factor.
Intense and long lasting stimuli facilitate sustained attention and result in better performance. Temporal uncertainty is a third factor. When stimuli appear at regular intervals of time they are attended better than when they appear at irregular intervals. Spatial uncertainty is a fourth factor.
Stimuli that appear at a fixed place are readily attended, whereas those that appear at random locations are difficult to attend. Attention has several practical implications. The number of objects one can readily attend to in a single glance is used to design the number plates of motorbikes and cars so that the traffic police can easily notice them in the case of traffic rule violations (Box . ).
A number of children fail to perform well in school simply due to the problem of attention. Box . presents some interesting information about a disorder of attention. This is a very common behavioural disorder found among children of the primary school age.
It is characterised by impulsivity, excessive motor activity, and an inability to attend. The disorder is more prevalent among boys than among girls. If not managed properly, the attention difficulties may persist into adolescence or adult years. Difficulty in sustaining attention is the central feature of this disorder, which gets reflected in several other domains of the child.
For example, such children are highly distractible; they do not follow instructions, have difficulty in getting along with parents, and are negatively viewed by their peers. They do poorly in school, and show difficulties in reading or learning basic subjects in schools in spite of the fact that there is no deficit in their intelligence. Studies generally do not provide evidence for a biological basis of the disorder, whereas some relationship of the disorder with dietary factors, particularly food colouring, has been documented. On the other hand, social-psychological factors (e.g., home environment, family pathology) have been .