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Date posted: November 30, 2011

Attention is the cognitive process of selectively concentrating on one aspect of the environment while ignoring other things. Examples include listening carefully to what someone is saying while ignoring other conversations in the room.

In other words attention is the first step in the observation.  It is focusing the consciousness on a stimulus. It is a process of preferentially responding to a stimulus or a range of stimuli.

Attention can also be split, as when a person drives a car and talks on a cell phone at the same time. Sometimes attention shifts to matters unrelated to the external environment, a phenomenon referred to as mind-wandering or “spontaneous thought”.

Attention is one of the most intensely studied topics within psychology and cognitive neuroscience. Of the many cognitive processes associated with the human mind (decision-making, memory, emotion, etc), attention is considered the most concrete because it is tied so closely to perception.  As such it is a gateway to the rest of cognition.

Definition by William James

One of the first major psychologists, William James, defined attention as follows:

“Everyone knows what attention is. Focalization, concentration, of consciousness are of its essence. It implies withdrawal from some things in order to deal effectively with others, and is a condition which has a real opposite in the confused, dazed, scatterbrained state.” (Principles of Psychology, 1890)

Definition by Titchner  “Attention is a state of sensory clearness with a margin and a focus.  Attention is the aspect of consciousness that relates to the amount of effort exerted in focusing on certain aspects of an experience, so that they become relatively vivid”. 

History of the study of attention

1850s to 1900s
In James’ time, the method more commonly used to to study attention was introspection. However as early as in 1858 Franciscus Donders used mental chronometry to study attention and it was considered a major field of intellectual inquiry by such diverse authors as Sigmund Freud, Walter Benjamin, and Max Nordau. One major debate in this period was whether it was possible to attend to two things at once (split attention). Walter Benjamin described this experience as “reception in a state of distraction.” Some thinkers felt that they were unable to do so, and other thinkers felt that they could. This disagreement could only be resolved through experimentation. 

1900s to 1950s
From the 1900s to the 1950s, the field of attention was relatively inactive as the dominant psychological paradigm at the time was behaviorism. Behaviorism was rooted in positivism, an epistemology that rejects the study of, and the making of assumptions about, processes that that cannot be observed directly such as cognition, gravitational forces in Physics etc. Thus cognitive processes do not govern attention and attention is best viewed as a form of behavior that can be understood through purely objective experimental analysis. 

1950s to present
In the 1950s, research psychologists renewed their interest in attention when the dominant epistemology shifted from positivism to realism during what has come to be known as the “cognitive revolution” (Harré, 2002). The cognitive revolution admitted unobservable cognitive processes like attention as legitimate objects of scientific study. 

Colin Cherry and Donald Broadbent, among others, performed experiments on dichotic listening. In a typical experiment, subjects would listen to two streams of words in different ears of a set of headphones, and selectively attend to one stream. After the task, the experimenter would ask the subjects questions about the content of the unattended stream.

During this period, the major debate was between early-selection models and late-selection models. In the early selection models, attention shuts down processing in the unattended ear before the mind can analyze its semantic content. In the late selection models, the content in both ears is analyzed semantically, but the words in the unattended ear cannot access consciousness. This debate has still not been resolved.

In the 1960s, Anne Treisman began developing the highly influential Feature integration theory (first published under this in a paper with G. Gelade in 1980). According to this model, attention is responsible for binding different features into consciously experienced wholes. Although this model has received much criticism, it is still widely accepted or held up with modifications as in Jeremy Wolfe’s visual search paradigm.

In the 1960s, Robert Wurtz at the National Institutes of Health began recording electrical signals from the brains of macaque monkeys who were trained to perform attentional tasks. These experiments showed for the first time that there was a direct neural correlate of a mental process (namely, enhanced firing in the superior colliculus).

In the 1990s, neuroscientists began using fMRI to image the brain in attentive tasks. The results of these experiments have shown a broad agreement with the psychophysical and monkey literature.

Current research
Attention remains a major area of investigation within psychology and neuroscience. Many of the major debates of James’ time remain unresolved. For example, although most scientists accept that attention can be split, strong proof has remained elusive. And there is still no widely accepted definition of attention more concrete than that given in the James quote above. This lack of progress has led many observers to speculate that attention refers to many separate processes without a common mechanism.

Areas of active investigation involve determining the source of the signals that generate attention, the effects of these signals on the tuning properties of sensory neurons, and the relationship between attention and other cognitive processes like memory. Some speculative research has shown that even flies may be able to attend using poppy seed sized brain in much same way neurologically as humans do.

Clinical model of attention
Many times clinical models differ from investigation models. One of the most used models for the evaluation of attention in patients with very different neurologic pathologies is the model of Sohlberg and Mateer.[2] This hierarchic model is based in the recovering of attention processes of brain damage patients after coma. Five different kinds of activities are described in the model; connecting with the activities that patients could do as their recovering process advanced.

  • Focused attention: This is the ability to respond discretely to specific visual, auditory or tactile stimuli.
  • Sustained attention: This refers to the ability to maintain a consistent behavioral response during continuous and repetitive activity.
  • Selective attention: : This level of attention refers to the capacity to maintain a behavioral or cognitive set in the face of distracting or competing stimuli. Therefore it incorporates the notion of “freedom from distractibility”
  • Alternating attention: it refers to the capacity for mental flexibility that allows individuals to shift their focus of attention and move between tasks having different cognitive requirements.
  • Divided attention: This is the highest level of attention and it refers to the ability to respond simultaneously to multiple tasks or multiple task demands.

This model has shown to be very useful to evaluate attention in very different pathologies, correlates strongly with daily difficulties and it is specially helpful to design stimulation programs such as the APT (Attention process training); a rehabilitation program for neurolgic patients.

Overt and covert attention
Attention may be differentiated according to its status as ‘overt’ versus ‘covert’. Overt attention is the act of directing sense organs towards a stimulus source. Covert attention is the act of mentally focusing on particular stimuli. Covert attention is thought to be a neural process that enhances the signal from a particular part of the sensory panorama.

There are studies that suggest the mechanisms of overt and covert attention may not be as separate as previously believed. Though humans and primates can look in one direction but attend in another, there may be an underlying neural circuitry that links shifts in covert attention to plans to shift gaze. For example, if individuals attend to the right hand corner field of view, we want to move eyes in that direction, and have to actively suppres the eye movement that linked to this shift in attention.

The current view is that visual covert attention is a mechanism for quickly scanning the field of view for interesting locations. This shift in covert attention is linked to eye movement circuitry that sets up a slower saccade to that location.

Factors Influencing Attention

  • Objective factors(characteristic of stimuli)
  • Intensity of stimulus
  • Frequency of repetition
  • Size
  • Movement
  • Change of stimuli
  • Novelty
  • Subjective (Qualities of the observer)
  • Habit or familiarity
  • Immediate need
  • Profession – interest or motivation
  • Innate tendencies 

Neural correlates of attention
Most experiments show that one neural correlate of attention is enhanced firing. If a neuron has a certain response to a stimulus when the animal is not attending to the stimulus, and then when the animal does attend to the stimulus, the neuron’s response will be enhanced even if the physical characteristic of the stimulus remains the same. A strict criterion in this paradigm of testing attention is that the physical stimulus available to the subject must be the same, and only the mental state is allowed to change. In this manner, any differences in neuronal firing may be attributed to a mental state (attention) rather than differences in the stimulus itself.

In this context it is instructive to mention the Necker cube illusion as an example of the mental perception of a stimulus changing, even though the stimulus itself is unchanged. A recent neural study in monkeys claims to have found a neural correlate to the Necker cube illusion.

Attention can also be considered in terms of its underlying anatomy. It is useful for educators to think about attention as an organ system like systems of respiration and circulation. Attention has a distinct anatomy that carries out basic psychological functions and that can be influenced by specific brain injuries and states. The network involved in achieving an alert state involves midbrain centers that are the source of the chemical norepinepherine. This network appears to be asymmetric at the cortical level, with greatest involvement of the right cerebral hemisphere, particularly in the frontal regions. Two networks are involved in the process of selection of information. One of these relates to orienting to sensory information, and involves areas of the parietal lobe, frontal eye fields, and superior colliculus, which are also part of the eye movement system. A second network is related to attention to internal thoughts. This network involves areas of the frontal midline (anterior cingulate), the left and right lateral prefrontal cortex, and the underlying basal ganglia.

Intact arousal mechanism is essential to maintain alertness, which is a function of ascending reticular activating system.  Cortical and limbic structures are involved in focusing the ascending activation.  Thus attention and vigilance results from a complex interaction between limbic neocortical and ascending activating system.  Brain stem lesions lead to reduce the alertness and secondary impairment of attention.  Diffuse cerebral dysfunction resulting from toxic or metabolic encephalopathy is the commonest cause for impaired attention.  Bilateral frontal lobe lesion or limbic involvement (example; Korsakoff’s psychosis) leads to inattention that is characterized by indifference and perseveration.

Characteristics of Attention
The process of attention divides our field of experience into a focus and a margin.  Events that we perceive clearly are at the focus of experience.  Other items are perceived dimly; we may be aware of their presence, but only vaguely so.  These items are in the margin of attention.

For example, consider your reaction at football game. When game is going on , your attention is focusing on the ball carrier and his movements. At the same time you have been suffered by the number of stimuli. Your feet may be aching ,  there may be unpleasant sensation in the stomach etc..While play is going on you are not aware of any of these that are in the margin of your attention. Only when the play is finished you perceive the pain and unpleasant sensation in the stomach

Focus and margin of the attention is constantly shifting.  What is at the focus one moment may be in the margin the next and what is in the margin may become the focus.

Attention and the Processing of Information
This can be explained using the concept of filtering .  Since we can not process all the information in our sensory channels, we filter or partially blackout some inputs.

Imagine you are standing between two groups of people who are simultaneously carrying on two different conversations.  You may be able to pick up some of both conversations at the same time called as parallel processing.  But you will probably find that one or other conversation is at the focus of your attention at any given moment.  It is hard to pay attention to more than one set of inputs at a time.  This is called as serial processing, that is attending one set of inputs and then another.  Whether you process the conversation serially, or listen to only one of them, you are filtering out the unattended conversation.  In the filter model of attention inputs in the margin shift to the focus, when various attending getting features of the environment are present in the filtered input.

Human attention
The members of a species are attentive to the function of their evolutionary and cultural history. In the case of humans, there are problems presented by ecosystem changes resulting from human mobility and cultural artifacts. Humans no longer live in the ecosystem they evolved in, but rather in an ecosystem of their own creation. For example, humans are attracted to sweet food, an adaptive trait for hunting and gathering, but not so adaptive for modern nutrition (high sugar intake is a major cause of heart disease).

A more substantial problem is presented by the human propensity to focus on emergency situations even to the exclusion of background phenomena which may be more significant. This can be seen in what is considered news, where a spectacular auto-accident easily outweighs a report on particulate pollution; although only a few may have died in the accident, thousands may suffer and die due to smog-related illnesses.

Humans, like all animals, respond more readily to novel objects and fast changes. This is why predators evolve to blend with their surroundings and move very little while stalking prey. Novel objects and fast changes are more likely to carry new information and may be more profitable to analyze in greater detail than older objects that have already been inspected or slower changes that may not be an immediate concern. 

Assessment of Attention

Attention span
Attention span is the amount of time a person can concentrate on a single activity. The ability to focus one’s mental or other efforts on an object is generally considered to be of prime importance to the achievement of goals. People usually have a longer attention span when they are doing something that they enjoy.

In a study of 2,600 children ages 1 to 3 published in 2004, a team of researchers from University of Washington found that early exposure to television may have a negative impact on attention span. It has also been suggested that internet browsing can have a similar effect. Attention span while working on a computer is in the range of one second or less. If it takes any longer than a fraction of a second for the computer to respond to an instruction, (such as performing a search or hitting the back-arrow key), the human brain starts to wander off task.

The average attention span of a person is 2-5 minutes times their ageso a 5-year-old would have an average attention span of 15-25 minutes. Elementary education often helps to extend or develop attention span in children. A common myth, quoted by many teachers, that a person’s attention span is 10 + person’s age minutes, and that anything taught after that is not taken in, but by taking a 5-10 minute break after this time will help the class recover and replenish their attention span, but there is no evidence that this is actually successful.  In children it is said that their attention span is about a minute for every year of their lives.

Attention span can be assessed clinically by using the following test

1) Ask the patient to name the month of the year or days of the week forwards or backwards

2) Digit span test – it is an easy method to assess the basic level of attention.  The examiner verbally presents a series of digits in the order of one per second.  One should begin with a two digit sequence and go on increasing it to 3,4,5, and so on.  Taking care to present them slowly, distinctly and without grouping them.  He then asks the patient to repeat the digit series.  A patient with normal intelligence will be able to repeat five to seven digits forward and 4 to 5 digits backwards without difficulty.  Later the examiner presents a new series of digits and ask the patient to repeat in the reverse order.

3)Serial subtraction test – It is a simple and useful procedure.  The patient is asked to mentally subtract seven from hundred (or some other digit) serially up to the number less than seven.  It is important to observe the pattern of sustained concentration in performance rather than the accuracy of mathematical operation.  Usually the performance can be accepted as normal, if the time taken is less that two minutes and the patient has not committed more than two errors.

For those who can not do these serial subtraction, their attention can be assessed by a simple method, that is asking the patient to count backwards from twenty to one

4) Random letter test – Examiner reads a long series of random letters, among which a target letter (Example; A) appears with a greater that random frequency.  The patient is asked to indicate whenever the target letter is spoken by tapping the desk.  The common organic errors are a) Omission, b) Commission error ie; the patient indicate where a non target letter is presented, c) perseveration error – where the patient fails to stop tapping with the presentation of subsequent non target letters.

5) Face hand test – where two stimuli are given simultaneously over the face and a hand.  Patient with organic brain syndrome fails to recognize the hand stimulus even on repeated stimuli.  The test may be abnormal even in the normal individuals above 65years.

Clinical Applications

Attention deficit / hyper kinetic disorders – ADHD

This is a syndrome first described by Heinrich Hoff in 1854.  It has been known by a variety of names like minimal brain dysfunction (MBD), Hyper kinetic syndrome, Strauss syndrome and Organic drivenness.  This is thought to be a neurological disorder always occurring in about three percentage of school age children.  Males are six to eight times more often affected.  The onset occurs before the age of seven and a large majority of patients exhibit symptoms by the age of four.

Etiology
Many factors like minimal brain damage, malnutrition, genetics, neurotransmitters (nor epinephrine and dopamine) and early developmental psychodynamic factors have been incriminated.  The exact etiology is not known but it is more likely to be a biological factor than a purely psychosocial one.

Classification

Mainly four clinical types

  • Attention Deficit Disorder with hyperactivity (Hyperkinetic Disorder)
  • ADD without hyperactivity
  • Residual type
  • Conduct disorders

a) Hyperkinetic Disorder

This is the commonest type

Clinical features are

I)   Poor attention span with distractibility

  • Fails to finish the things started
  • Shift from one uncomplicated activity to other
  • Does not seem to listen
  • Easily distracted by external stimuli
  • Often loses things

II) Hyperactivity

  • Fidgety
  • Difficulty in sitting still at one place for long
  • Moving about here and there
  • Talks excessively
  • Interference in others activities

III) Impulsivity

  • Acts before thinking
  • Difficulty in waiting for turn at work or play

b)    ADD without hyperactivity

  • It is a rare disorder with similar clinical features except hyperactivity

c) Residual type

  • It is diagnosed in a patient with a past history of ADD and presence of a few residual features in adulthood.

d) Conduct disorder

This is characterized by a persistent and significant pattern of conduct in which the basic rights of others are violated or rules of the society are not followed.  The clinical features include

  • Frequent lying
  • Steeling or robbery
  • Running away from home and school
  • Physical violence like rape, fire setting, assault or breaking in, use of weapons etc.
  • Cruelty towards other people and animals

Diagnosis
It is made on the basis of

  • Teacher’s school report
  • Parent’s report
  • Clinical examination

Treatment

  • Pharmaco therapy
  • Behavioral therapy
  • Counseling and supportive psycho therapy

Comments

2 Responses so far.

  1. shreya says:

    i liked the aptness of the info.

  2. shreya says:

    i liked the precision of the information.

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