Sustained Attention Definition and Theories

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Basil Manning
Sustained Attention Definition and Theories

Introduction

Staying attention doesn't have to be difficult. There is an attentional phenomenon called "attentional inertia" which says that if attention has been held for more than 15 seconds initially, it is easier to hold it continuously. Sustaining attention can be easy for interesting activities or those that are done in a pleasant environment.

Many contributions from psychology have emerged in this field. We are going to see them.

Definition and Concept

Sustained attention is the activity that sets in motion the processes and / or mechanisms by which the body is able to maintain attention focus and remain alert to the presence of certain stimuli for relatively long periods of time. SUSTAINED CARE = ​​PERSISTENCE OF CARE.

By keeping our attention, on many occasions deterioration can occur, which can be expressed in 2 ways:

  • Decrease in vigilance / Decrease function / Attention impairment - Due to the progressive decrease in the performance of the task over time.
  • Surveillance level: Due to the decrease in the level of execution of the task as a whole and not over time. Investigations have focused, above all, on the "decrease in surveillance." produce at the attention level? The most typical effects that surveillance tasks have on attention are 2:
  • Distractibility: The subject begins to develop more dispersed attention and is easily distracted.
  • Attention lapses: Decreases in activation levels evidenced by a decrease in the intensity of attention.

Sustained attention, alert and vigilance: terminological details

In the words of Parasuraman: "the ability to maintain attention and remain vigilant for such events for sustained periods of time forms the focus of research on sustained attention or vigilance".

Sir Henry Head defined surveillance as "a highly efficient state of the central nervous system." From then on, the relationship of the theoretical construct surveillance with the concept of physiological activation or arousal was unequivocal: the arousal referred to the efficiency of the nervous system when receiving or capturing information, in such a way that a high efficiency of the system nervous when receiving or capturing information is what made an organism remain vigilant or in a state of alert.

But Mackworth took the word surveillance from Henry Head and used it to refer to the "willingness of the body to respond effectively." The concept of "surveillance" was directly related to the issues of sustained care and progressively, the term "surveillance" has come to replace the term "support" or "maintenance of care.".

In short, there is a close relationship between the concepts of arousal, vigilance and sustained attention; but there are also relevant differences:

-For persistence of attention to be effective, it is necessary for the body to have minimum levels of activation.

-The "arousal" is a general state of the body that affects various functions of attention.

-The concept of vigilance is currently used to describe a specific type of sustained attention tasks.

Intensive Aspects of Sustained Attention: Attention Fluctuations and Sustained Attention.

It is very difficult for us to maintain attention for long periods of time. The receptivity of the nervous system is not always the same, and sometimes there are important changes in the levels of alertness and vigilance..

On some occasions it has been considered that talking about sustained attention and intensive attention processes is almost the same. But it's not like that. In the same way that we saw that "sustained attention" and "vigilance" are not the same, neither are "sustained attention" and "intense attention":

In the first place, because whenever selective, dividing or sustaining attentional mechanisms are set in motion, certain levels of intensity of attention are needed, thus, intensive processes of attention are directly related to all mechanisms or attentional operations.

Second, sometimes a certain deterioration in the execution of surveillance tasks can be observed, even when the levels of intensity of attention are high. This is due to the mediation of other factors that also significantly influence the execution of this type of task..

If the decrease in the intensity of attention is one of the most typical manifestations of surveillance tasks, also the continuous oscillations of attention and distraction are important phenomena that take place under this type of task..

Changes in the intensity of attention can be of two types: short and transitory, and long and relatively permanent. The first, known by the name of phasic change, gives rise to the concept of phasic alert; and the second called tonic change, gives rise to the concept of tonic alert.

The concept of tonic alert refers to the general level of activation of the organism (arousal). It is characterized by not suffering sudden changes in intensity, they are relatively slow and spaced changes in time.
Phasic alertness occurs when the subject is required to pay continuous attention to events in the environment. Under these circumstances there are changes in the alert levels that are known as phasic changes. Specific:

  • At first, the organism is under a transitory state of readiness to process the critical stimulus. At the moment, the phasic levels are quite high.
  • Throughout an attention task, phasic levels of alertness can fluctuate considerably, leading to the famous lapses of attention.The concepts of tonic alertness and phasic alertness are not mere psychological constructs, but physiological correlates have been established. of both types of alerts. In the case of the tonic alert, the basic correlate is the physiological arousal, while in the case of the phasic alert, the most important indicators are the traces of the electroencephalographic waves and, very especially, the evoked potentials..

Historical development of surveillance studies

The phenomenon of "decreased performance" in surveillance tasks has been considered the ubiquitous finding in sustained attention experiments. In fact, practically all the investigations into the maintenance of attention have revolved around the phenomenon of decreased execution in surveillance tasks. But how has the study of sustained attention progressed??

It started with the waning of attention on radar watchers from World War II. Attempts to determine why this change occurred led to the development of research on the problem of sustained attention. The first laboratory work began with Norman Mackworth, who first used the concept of surveillance by creating surveillance tasks in the laboratory..

Based on the Mackworth studies, the research focused on analyzing whether or not the decrease actually occurs and under what conditions. Mackworth began to experiment with his "clock test" (a simulated radar whose results showed that the frequency of undetected signals increased sharply from the first to the second half hour of the session, then showed a gradual drop in the hour and a half remaining), but others made their modifications.

Some investigations revolved around the presentation of auditory stimuli as critical signals, or very brief signals that remained until the subject gave a response (called by Broadbent as “limited hold” and “unlimited hold” signals). Sometimes the subject had to detect signals and at other times discriminate them.

Later the "Theory of Signal Detection" (TDS) arises within the framework of Psychophysics, a discipline interested in the study of sensation and sensory quantification. For TDS, a typical signal detection task consists of detecting a signal that occurs on a noise background, which does not replace it, but adds it to the background noise ceiling.

The task of the subject is to decide if the sensation X that he has at a certain moment is a consequence of perceiving the signal against the noise background (SR), or is only the result of perceiving the noise background only (R).

The basic assumption of this theory is that any signal detection task includes two basic processes:

  • Sensory processes or perceptual sensitivity, which is the ability of the subject to distinguish between signals and non-signals.
  • Processes related to the subject's decision criteria. These processes act when the subject is uncertain about whether the signal is really present. In these cases, a series of variables influence: the expectations that one has that the signal will appear; and the motivational system that the experimenter himself can provoke.

One of the main contributions of the TDS has been to evaluate the response of the subject in a much more complete way. The TDS discriminates between 2 types of hits (correct detections and rejections) and 2 types of errors (false alarms and failures). But its most important contribution has been to obtain 2 response parameters:

The sensitivity or ability to perceive a sensory stimulus (d ́). This variable is also known by the name of detectability.

The decision criterion or level of risk that the subject is willing to assume when situations of uncertainty occur (β).

A subject may have very good sensory capacity and, in the few trials in which they have uncertainty, they may be either risky or conservative in their decision making..

The TDS has been applied to various fields of study and especially to the study of surveillance tasks.

Determinant Factors in Surveillance Tasks

The impairment of attention is a general phenomenon in surveillance tasks; However, the one that appears more or less soon and in a more or less accentuated way depends on a series of variables. Research in the 60s and 70s has focused on studying much more systematically how certain variables influence the performance of this type of task..

While the bulk of the work in the 1960s was clustered around a field that is often known by the name of psychophysics of surveillance, today the interest lies more in the cognitive demands of the tasks. Two other important lines of work are studies on lack of sleep and the role of stress.

Psychophysical characteristics of critical signals

Sensory modality of critical signals:

In general terms, it has been observed that there is greater efficiency in performance when tasks are auditory than when they are visual.

If it is a question of maintaining attention in several sensory modalities at the same time, the deterioration in the execution in one of them is usually betrayed in a more noticeable way. On the other hand, the experience acquired in one sensory modality can influence the performance of another sensory modality..

Striking features of the signs:

The signal can be striking in its intensity and duration. The stronger and longer-lasting the signal, the easier it is to detect.

Presence of a noise background

It has been investigated how the introduction of background noise influences sustained attention. The results that have been obtained have been diverse. From these results it has been deduced that the background noise variables that influence attention are the intensity and continuity of the noise. From this mode, moderately intense and continuous noise can promote sustained attention, while intense and intermittent noise makes attention quite difficult..

Background event rhythm

The rhythm of the background event appears in tasks in which stimuli are constantly presented, of which the vast majority are the same and a few are different, and the subject must detect the different ones. By rhythm of background events he refers to the speed with which the same stimuli are presented. Although background stimuli do not require a manifest response on the part of the subject, it seems that the frequency with which they occur does determine performance in sustained attention tasks.

In summary, the results obtained show that, when the rhythm of events is manipulated, the faster the background events, the worse the performance in the surveillance task..

Task complexity

Obviously, surveillance tasks can be multiple and varied, and consequently present a greater or lesser level of complexity. Some features that define this level of difficulty are the following:

a) Number of signals presented: the greater the number of critical signals that the subject must detect, the worse the performance. The situation worsens when each signal must respond with a different response.

b) Multiple channels: normally the more sensory channels that are included in the task, the worse the performance. However, the performance may increase if the signals from different channels are synchronized well (for example, if very shortly after a visual signal is presented an auditory signal is presented, the performance will improve because being synchronized we know that after a the other comes).

c) Rhythm of presentation of the critical signal: Also known as the stimulation rhythm or event rate, this variable refers to the density or number of critical signals that appear throughout the surveillance task. It partly determines the degree of control the observer has over when the signal will appear. This dimension is also known as the temporal uncertainty of the signal..

It is usually divided into two categories: low density, when it occurs less than 24 times per minute, and high density, when the signal occurs 24 times or more. It is observed that the more frequent the signals are in a fixed period of time, the less uncertainty the observer has about when they will appear..

d) Level of discrimination signal / non-critical tests: This variable is defined as the degree of discrepancy between the critical signals and the non-critical tests, and it is considered that, in those cases in which the critical signal is difficult to discriminate from the background noise or non-critical stimuli, the task demands a greater amount of attention resources on the part of the subject. That is why this variable is also sometimes known by the name of the task's workload..

e) Type of signal / non-signal discrimination: there are two types of signal discrimination: 1) Simultaneous discrimination: in this type of discrimination, the subject only has to discriminate if a critical signal is present without the need to compare it with a criterion signal (for example, discriminate a certain auditory tone on a white noise background); 2) Successive discrimination: in this type of discrimination, the subject must discriminate a criterion stimulus from other stimuli that differ only in one characteristic (for example, discriminate one light from another only by increasing its intensity).

Successive discrimination requires that more cognitive resources be consumed than in sequential discrimination, so performance is lower in successive discrimination situations.

f) Predictability of the signal: a signal becomes predictable when the intervals between the signals have a similar duration. A signal that is predictable decreases temporal uncertainty, as does the rate of appearance of signals (or signal density). For this reason, predictable signals increase discrimination accuracy and reduce response time, that is, they increase performance..

g) Spatial uncertainty: This variable refers to the probability that the signal appears in different positions of the control mechanism. The general observation is that the probability of detecting a signal is higher in areas where the probability of the appearance of signals is higher..

Knowledge of performance results

Knowing the results (successes - errors) during the course of the task is always positive, even in those cases in which the subject is not fully informed.
The best performance occurs, first, when the results are reported verbally; secondly, when the knowledge of results is auditory, and thirdly when it is visual.

Regarding the content of the knowledge of results, it is indicated that:

  • When the subject is informed of the correct detections, then the number of inadvertent signals decreases.
  • When the subject is informed about false alarms, then the number of successful detections increases and the number of false alarms decreases..
  • When the subject is informed about the inadvertent signals, then the number of false alarms decreases.

Loss of sleep

In general terms, it can be affirmed that the loss of your year produces a decrease in the levels of activation that causes a general deterioration in the task that is observed from the beginning of it..

Among the theories that try to explain the influence of lack of sleep on attention, the hypothesis of lapses stands out. This theory maintains that when sleep deprivation occurs, oscillations in activation take place, which momentarily becomes higher than normally in which there is a deterioration in performance. Therefore the theory holds that insomnia produces an irregular and not general deterioration.

The results of the investigations on the hypothesis of lapses have shown that the deterioration in the execution of a task carried out by subjects with sleep deprivation occurs with more intensity at the end of the task. In another line of research developed by Concoran, activating stimuli are included during the execution of the task with sleep deprivation. The activation produced by activating stimuli such as noise or electric shocks is added to the very low levels of activation produced by sleep deprivation, so that the activation is at intermediate levels.

If what is manipulated is the intrinsic interest of the experimental subjects in the execution of the task, the prediction that is made is that the tasks that arouse greater intrinsic interest will present greater resistance to the effects of sleep. However, a study carried out yielded surprising results, since the tasks that had presented the greatest resistance to the deactivating effects of sleep were the tasks that the subjects evaluated as least interesting.

It should also be known that in order to resist the effects of sleep when carrying out a task, it is advisable for the task to have a high degree of complexity, and not for the task to be too simple..

Stress and vigilance

Various investigations have conceptualized stress as a property of the external environment. In the surveillance tasks, there have been 2 forms of environmental stress that have generated the greatest interest: noise and temperature. In recent years an assumption has emerged in which surveillance tasks are themselves a course of stress..

Thackray believes that the stress of surveillance tasks arises from having to maintain a high level of alertness during a monotonous situation while at the same time being unable to control what events may occur. And indeed, control over events seems to have a particular influence on the stress response. For example, Karasek has observed that the most stressful situation is one that combines extremes of demand and under control, while by varying the demand, stress can be lessened by increasing the subject's decision control..

Final considerations

The results obtained in a surveillance task based on a variable can be modified by the interrelation established with other simultaneous variables. This has led to comparisons between different types of tasks. The importance of following this strategy is that, if we find important correlations, we can classify and combine different types of tasks.

The first results showed that the correlations between the different surveillance tasks were low. Instead, they recently show higher intercorrelations between surveillance tasks. Certain authors have developed a taxonomy of different types of surveillance tasks based on the correlations obtained. See table 6.1. (p. 154): Example of classification of surveillance tasks based on a series of criteria.

Current research postulates that the decrease in surveillance is due to the prosecution demands of the surveillance task. However, the influence of emotional and motivational factors is increasingly being taken into account. Blanco, Lamas and Álvarez conclude that "it is possible that the way in which the subjects approach the task is an important predictor of the decrease in vigilance".

Surveillance Theories

There have been several theories that explain why the phenomenon of impaired attention occurs during surveillance tasks. Each of them has used a different theoretical construct (expectation, arousal, habituation, etc.). Now we will analyze the most relevant.

Activation theory / arousal theory / arousal theory

The activation theory proposes that for a surveillance task to develop correctly without impaired attention, it is necessary for the task to have activating stimulation, since if the activation is reduced below the critical level, the impairment of attention. This theory postulates that due to the fact that surveillance tasks are monotonous, it is very easy for the activation level to end up being lower than the critical level, producing the impairment of attention.

There have been many investigations that have observed a correlation between the level of alertness and neurological activity. Thus, when the level of vigilance decreases, the electrocortical activity is reduced, the conductance of the skin decreases and it has also been observed that with stimulant drugs (amphetamine, cocaine) the surveillance tasks improve as well as they worsen when the subject uses drugs that depress the CNS (alcohol).

The results seem to indicate that the level of activation influences the efficacy in surveillance tasks, however some criticisms of these theories have been proposed:

  • It has been observed that decreasing activation below a critical level not only impairs performance in surveillance tasks, but also worsens performance in any other task that is long and monotonous.
  • It has been observed that when activation is induced in the surveillance task by means of external stimulation, performance sometimes increases, but that performance decreases at other times. To explain this phenomenon, the Yerkes-Dodson Law has been used, which maintains that both an extremely low level and an extremely high level of activation correspond to a low performance.
  • Activation theory can only explain post hoc results so it has little predictive power.

The theory of signal detection

The theory of signal detection (TDS) defends that when a surveillance task takes place for a long period of time, the number of hits and false alarms decreases. According to the TDS, this occurs because the subject becomes more conservative in response while perceptual sensitivity remains stable. However, the empirical results do not always reveal the same, since sometimes the perceptual sensitivity can vary. This means that changes in vigilance cannot be attributed solely to perceptual sensitivity..

Parasuraman observed what happens to the decision criteria throughout the task. In the first place, he observed that the rate of detection of signals (whether or not the signals existed) increased with the course of the surveillance task, so it can be deduced that the decision criterion decreases as the task progresses (the precision per both decreases because the subject is more risky). As for the response latency, it increases with positive detections (hit and miss), while it remains stable with negative detections..

The Expectation Theory

The expectation theory maintains that the fact that a subject has expectations of when the signal will appear greatly influences the performance of the surveillance task. In this way, the theory holds that the decrement function occurs because the subject has difficulties in predicting when the signal will appear..

This theory has strong experimental evidence, since it has been shown that subjects who go through a training phase in which they get an idea of ​​the predictability of the signal perform better in the surveillance task than subjects who have not passed. for said training phase. Despite this evidence that favors this theory, it has been criticized because the postulates it proposes do not really explain many aspects of surveillance tasks..

The theory of habituation

The habituation theory holds that the repeated presentation of irrelevant signals has the consequence that the subject becomes habituated and diminishes his attention and ability to detect the signals. Habituation and therefore performance deficit will occur more quickly when irrelevant signals are presented quickly and regularly.

Other theories

Theories of automaticity stand out. One of the objectives has been to analyze to what extent different types of tasks are automatic or controlled, or which components can be defined as automatic and others as controlled. One of the tasks precisely analyzed has been the surveillance task. According to these theories, the most important characteristics of this type of task are:

The surveillance task is defined as a controlled task that requires effort. Since this effort must be applied continuously, the subject is exhausted and performance begins to deteriorate..
The decrease in sensitivity in surveillance occurs because the distribution of processing resources for detection begins to decrease over time.

However, a surveillance task is very difficult to automate due to the infrequency and irregularity of the appearance of the targets. According to Parasuraman, a major problem with automaticity theories is the difficulty of measuring, separately, processing resources and effort, not only in surveillance tasks, but in any activity in general..

Final considerations

No theory outlined can satisfactorily justify all the results. A first explanation given is that some of these constructs are not really appropriate or valid to explain the decrement function in all cases. A second reason referred to is that these theories have focused on explaining only the phenomenon of decreased surveillance.

A third reason is that it may be inappropriate to approach surveillance as a unit effect. Under the generic name of surveillance task, many different tasks have been used, and until the 1970s authors have not paid much attention to what these tasks had and did not have in common. Until then it had been assumed that any theory could explain the execution for any surveillance task. The idea that the information processing demands for each surveillance task can be totally different is increasingly accepted..


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