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Chapter 3: Attention and Consciousness

A few basic definitions:

The Nature of Attention and Consciousness

It is in the nature of attention to be selective. We are constantly bombarded by sensory stimuli from the outside, as well as internal information pertaining to the state of our minds and bodies, as well as emotions and memories that they evoke. An individual's mental faculties provide the ability to focus on only so much of it, and far less than all of it even in the most attentive individual.

The processes by which we filter information are not entirely under our control: we have come capacity to decide what to give attention, but cannot stop ourselves from noticing some things or maintain focus on others.

Consciousness, meanwhile, merely involves the state of being aware of stimuli, regardless of whether attention happens to be focused upon it.

As such, the two are considered to be part of a continuum: we are not conscious of everything, and we do not focus attention on everything of which we are conscious.

Attention and consciousness are thus very basic elements in understanding cognition - to think about something requires us to be conscious and attentive. But at the same time, there are areas in which human behavior is unconscious or inattentive, and analyzing them as if they are the product of cognitive processes leads us astray.

Preconscious Processing

We are not conscious of every stimulus that reaches our senses - this information is available to consciousness, but much of it is filtered out. This pertains to external and internal stimuli as well as memory.

For example, most people who view a photograph of another person will notice details about that person - their gender, race, facial expression, posture, etc. - as well as key objects. But there will always be details they will not notice, such as the color of the chair on which they were sitting or whether they were wearing a ring. Few people have a perfect memory and can recall minute details, and even they recall more than the average person but not everything.

The same is true of memory. Stored memories are idle until they are triggered: you probably weren't thinking about the color of the blanket on your bed - but now that it's been mentioned you can't help recalling it.

Psychologists have also identified a phenomenon known as

"priming," in which recent experience influences cognition. The example given is of a person who has heard someone speaking excitedly about a satellite television system - and if he hears the word "dish" later that day, his mental image will be of a satellite dish, when it might otherwise have been of a dinner plate. The subject may recognize the connection, or he may have forgotten the conversation altogether - but his mind is "primed" to think in a certain way based on it. The priming phenomenon can readily be observed when a single word represents multiple possible association: a palm can be part of the hand or a tree, a leg may be a human body part or part of a table, and so on.

It's noted that priming requires attention and an extended period of time: a conversation of some minutes may prime the mind, but an experiment in which words and images were "flashed" for a matter of milliseconds did not result in a significant difference between test and control groups. (EN: Which is likely important to mention because "subliminal" advertising is alleged to prime a subject by exactly this method.)

Other experiments suggest that this priming depends on current memory and perception: "palm" can be associated to "tree" but not to a random object. Also, recall is improved when items are associated to a common element. The words "playing," "credit," and "report" are easier to recall because all three are associated to "card" whereas other groupings with no common element are not as easily recalled.

Another reference is made to mental blocks, such as when we forget a word we know, and feel it is on the tips of our tongues. Experimentation using a dictionary game (given a definition and asked to guess the word) showed that subjects who forgot a word would struggle, and often identify another word that starts with the same letter and has the same number of syllables.

(EN: This seems to become unraveled at the end ... and I do wonder if the author quite made his point here.)

Controlled and Automatic Processes

A distinction is drawn between two types of processes. Automatic processes occur without conscious control: the subject may be aware of them, but they demand "little or no" attention. Controlled processes require a level of intent and awareness to perform and generally take longer to execute.

Naturally, there is some debate as to which processes fall into which category - by some definitions, tying your shoes is an automatic process, because while they physical activity is entirely voluntary, there is no mental process involved - you do not deliberate over how to go about it and don't concentrate on doing it. Physically it is a voluntary action, but cognitively the process is automated.

Automatic processes are often concealed from consciousness, they require no concentration, and they consume few mental resources. Some cannot be consciously controlled at all, whereas others can be controlled but generally are not.

Automated processes include tasks that are learned by rote and performed frequently enough that they do not require attention: tying you shoes, riding a bicycle, and walking up stairs are all things people learned to do, and which required some effort at first, but with time and repetition they became automated (or "automatized"). An example to which adults can relate is speaking in a foreign language, which requires intense concentration until they have developed a familiarity, at which point they develop the ability to express themselves fluently, without deliberating over each word.

One theory of the way in which this occurs suggests that tasks are grouped into integrated components, such that they become a single step rather than many shorter ones, and over time the steps are aggregated to a single unit. This was deduced from observing telegraph operators - who begin tapping out letters, but eventually learn to tap out common words, and later entire phrases.

Another theory suggests that task automation is similar to conditioned behavior - that a sensory cue is associated to a sequence of activities. For example, the sight of a red light triggers all of the physical motions necessary to stop a car, or the sound of an alarm clock triggers all the actions to turn of the alarm, switch on a lamp, and rise from the bed. This theory explains the reason we find it difficult to do a familiar task under unfamiliar circumstances - when the signal is changed, the automation is derailed. This can also be done proactively in order to deviate when needed: to place a note on your coffee cup to remind you to bring something unusual to the office.

Studies into the process of automation suggest a curve. The amount of effort (measured in time) it takes to do a simple task the first time is not measured, but the second time it takes 25 "units", the third time only 20, the fourth 16, and so on, until the tenth time when it requires one unit (the arbitrary "unit" being the amount of time it takes an experienced person to do the task).

It's also suggested that once a task is automated, it becomes less efficient to attempt to control the task. That is, once a person has developed proficiency in riding a bicycle, concentrating on each physical movement actually makes them less efficient at the task.

Automated processes become stored in long-term memory. Using the same example, an adult who has never ridden a bicycle in years will quickly recall how to do it. It is for this reason that safety practices are studied. Consider that airline pilots spend considerable time training for situations like losing power to the engines on one side of the plane - they may never need to do this, but their training "kicks in" if they find themselves in such a situation. Especially when a quick response is needed to an emergency situation, people are better able to overcome panic when they execute an automated task rather than trying to figure it out in the moment.

There is, of course, the counterargument that automatic processes can have disastrous effects when a person follows a specific routine without paying attention. Another example from the airline industry is the pre-flight checklist, in which a pilot who has inspected his plane hundreds of times will look directly at a gauge that tells him the anti-icer is off, and check that it was on, because that's the way he was accustomed to seeing it. It's not always quite so dire, but fairly common for a person to drive directly home when they meant to stop at a store, or pour a glass of milk and put the carton into the cupboard rather than the refrigerator.

These "slips" are differentiated from "mistakes" in that a slip is entirely unconscious - and this is entirely because the routine has become automated that we go through the same steps without giving attention, or that a deviation fails to catch our attention, or that we fail to deviate when appropriate.

A list of slips is provided:

Habituation and Adaptation

Habituation involves becoming accustomed to stimuli, such that we pay less attention to them' it is countered by dishabituation, in which some change causes us to pay attention to details we'd previously ignored. These processes require no conscious effort, and can in fact defy conscious attempts to control.

For example, a student who is studying in a dormitory might be distracted by music playing in the next room. He returns to his studies an, in time, he no longer notices the music (habituation). Then his neighbor turns down the volume, and he suddenly becomes distracted again (dishabituation).

Both are modes of sensory adaptation: to limit our cognitive load, we ignore things that are familiar and giver attention to those that are unfamiliar or different. This is generally functional, but there are instances in which habituation can be dangerous, such as when assembly line workers become indifferent to machinery and become injured for failure to pay attention.

A few tips are provided to maintain mental focus:

  1. Take a break - Stepping a way from a prolonged task (such as driving for several hours) disrupts the stimuli to which we become habituated
  2. Alternate tasks - Similar to taking a break, doing something different interrupts the stimuli
  3. Take notes - When reading or listening, taking notes causes us to apply a conscious mental process
  4. Shift focus - When listening to a piece of music you have heard many times before, paying attention to the harmony rather than the melody can make you more attentive.

There are some instances in which attentiveness cannot be restored by a conscious process. Consider the sense of smell: when you first enter a room you will notice its distinct aroma, but within minutes you will become habituated to it, and there's nothing you can do to notice it (unless the stimulus changes).

In other terms, habituation is the lack of arousal in reaction to stimulus. "Arousal" itself is a term that refers to the amount of receptiveness, responsiveness, and general excitation in reaction to a stimulus - which can be measured by heart rate, respiration, and electrical activity in the brain. Levels of arousal are often measured when subjects cannot articulate their reaction to stimuli, or do not wish to do so. Arousal can even be observed in unconscious subjects (asleep or even comatose).

A sidebar is provided to distinguish adaptation from habituation:

The author returns to the notion of habituation as necessary to cognitive functioning: we cannot pay attention to all things at all times, and feel overwhelmed in an environment in which there are many unfamiliar stimuli. And while habituation can have negative consequences, it is generally beneficial to the subject.

Attention

Conscious attention is divided into three main functions:

  1. Signal Detection - The ability to be conscious of a given stimulus
  2. Selective Attention - The choice to give attention to certain things (and to ignore others)
  3. Divided Attention - The allocation of attention resources to multiple concurrent stimuli

Signal Detection

Because we are constantly bombarded by stimuli from the environment and our own bodies, the first step is sorting out which of the stimuli are meaningful - these are "signals," and four outcomes are possible:

Most commonly, when we increase our attention to discover hits, we also increase the number of false alarms, and when we decrease attention to correctly reject insignificant stimuli, we also tend to miss significant ones. However, because we generally are not aware that we are failing to notice things without an external prompt, we generally adjust sensitivity based on the number of hits and false alarms recognized.

The author likens this to airport screening: in the hijackings of 9/11/01, several of the hijackers were pulled aside and hand-searched after setting off metal detectors, but passed through in spite of the fact they had concealed box cutters on their persons - too low a level of sensitivity resulted in misses. Afterward, sensitivity was increased to the point that enfeebled elderly people and babies were being screened in defiance of logic - such that too high a level of sensitivity led to false alarms.

Vigilance

Vigilance refers to an ability to maintain attention to stimuli over a prolonged period of time, particularly during which the subject is likely to experience a lot of insignificant stimuli while attempting to be attentive to significant ones (such as a security guard or police officer) or to maintain focus to avoid errors while doing dull and repetitive work (quality inspectors and bank tellers).

An experiment (Mackworth 1948) asked participants to stare at the face of a clock, which was rigged to skip a minute at irregular intervals. Participants were asked to press a button at each skip, and their ability to do so accurately degraded to 75% after just half an hour. From the post-experiment interviews, it was found that people began to doubt their perceptions, and failed to press the button when they thought, but were not certain, they had noticed a skip.

Further research (Motter 1999) suggests that when an even occurs at a regular interval, subjects are less likely to fail to report it, but also are more likely to evoke a false alarm if the event fails to occur as expected. In visual tasks, the expected location of an event is also a factor that degrades accuracy.

Given this, the more vigilance a job requires, the more frequent breaks must be provided to workers to ensure their accuracy is preserved.

Search

Whereas vigilance entails passively waiting for some stimulus to occur, search is the active practice of seeking a specific stimulus. Specifically, it involves being attentive to sensory input and scanning the environment with a very specific goal in mind.

As an example, looking for a specific brand of cereal involves travelling to a grocery store, finding the cereal aisle, and searching the shelves for a box that elicits whose color, shape, and size match the desired item.

Search is made more difficult by the presence of distractors - items that mimic the desired stimuli, leading us to a false conclusion. This can be by virtue of the number of thins that naturally exist in a given location, or it may be an intentional deception - consider how closely store brands mimic national brands, which is an obvious attempt to fool the customer into picking up an item they didn't intend to get.

The most common type of search is a feature search, in which we consider the visual characteristics of an item we wish to locate. Consider the task of looking at a page and counting the instances of the letter "T" - we consider the shape of the letter to be its distinctive feature, which differentiate it from all other letters. In a grid of "O"s with only one "T" we can spot it immediately.

A conjugation search is slightly different: gross shapes are not enough to distinguish a "T" from an "L" because they are both composed of straight lines and a perpendicular conjunction. Instead, we must discern the way in which the shapes are joined. It is much more difficult to spot the single "T" in a grid of "L"s than a grid of "O"s.

Feature integration theory maintains that the more features we have to select from, the easier it is to find what we are seeking. Consider the example of store shelves: packages give us an array of features to integrate - we recognize a cereal box by its shape and size, and a given brand by color, typography, and images. The more distinctive features an item has, the easier it is for us to locate in an array of other items.

A separate feature inhibition mechanism function enables us to ignore selections that do not match search criteria. That is, when seeking a cereal that comes in a yellow box, feature matching would require checking each box for the color and paying attention to those that are yellow, whereas feature inhibition enables us to ignore any box that is not yellow - the difference is subtle, but ignoring items that do not match is far more efficient.

(EN: The author doesn't mention this, but it occurs to me that this is evident when we fail to recognize a person because they have changed a distinctive feature: we fail to recognize a person because they got a haircut, or are not wearing a necktie, etc. I don't think this pertains specifically to search, but to matching in general, and this is likely more in the nature of vigilance.)

Another search theory considers the matching process more holistically: we may be wholly unaware of the specific features that we are seeking, and have only a vague conception of what we are looking for, and give attention to things that seem similar in a general way, meanwhile ignoring things that are dissimilar in just as general a manner.

Searching therefore considers the sets of items in our field of perception, and winnows them down into groups in a more general manner: a person looking for a "B" in a field of random letters has a general sense that they are seeking something flat on the left and rounded on the right, focuses on characters BDPR, and does a closer inspection of each to find a perfect match.

There is also the notion that there is not a singular method of search that is universally applied: finding one letter in a grid of others is a much different cognitive puzzle that finding a shape of a given color and size in an array of objects that are scattered about an environment at various distances from the subject.

The theory of "guided search" seems to resolve some of these conflicts. By this theory, the subject considers what he is searching from, takes a glance at the objects in the environment among which he must search, and then decides how to proceed.

Consider looking for a person who is in a crowd of people: we are able to match the person to our memory at a glance, but given the complexity of the task, we purposefully determine how we will proceed: we recall that person had a certain hair color, or was wearing a specific garment, and use those as parameters to exclude or include members of the crowd from the search. The choice of criteria is often a conscious decision.

Movement-filter theory is also mentioned, which suggests that motion affects the ease and speed of search either positively or negatively. Generally, when the difference between the other visual elements (shape, size, color) is significant, some degree of motion facilitates search, but debilitates search when the differences are more subtle. If the movement is idiosyncratic to the item (all X move vertically while all O move horizontally), it becomes another feature against which we are able to match.

Prior knowledge also improves search speed and accuracy - if we have a general sense of where the item we are searching for will be located, we can more readily find it. For example, an accomplished typist can find a the "v" on a keyboard almost instantly whereas those who do not type regularly will take a few seconds to locate it.

Selective and Divided Attention

The author opens with a description of the "cocktail party problem" - a person who finds themselves unable to escape from a conversation with a very dull and talkative person finds it difficult to focus on the conversation and they are distracted by snatches of more interesting conversations other people are having, but must for social reasons appear to be interested in what the dullard is saying.

There is the notion that people are capable of giving attention to multiple stimuli, but this is not correct. They may be conscious of multiple stimuli, but can give their attention to only one related group of them. When a person is subjected to multiple stimuli, they follow one and ignore the other. They may switch their attention between the two, but this means they are giving intermittent attention to each.

Reference is made to an experiment (Duncan 1999) in which a subject heard one spoken list of items in one earpiece and a different one in the other - invariably, the subjects would mix the two lists. Further, when read two sentences, subjects would make one coherent sentence by combining both, and in extended experiments they failed to notice when one of the messages was shifted into another language or played backward for a time. This holds true even when there are different voices.

Returning for a moment to the notion of search, hearing one voice in a noisy room is similar to spotting one object in a grid of many: we use the distinctive sound of a given individual's speech, along with the volume, and along with the location from which the sound is coming to match a voice to a person - but the task of interpreting language is different to the task of recognizing voices, and in that regard the voices of many speakers become blurred - it becomes difficult to pay attention to any one person, or difficult not to synthesize meaning from the voices of many.

Filter and Bottleneck Theories

There are various theories of selective attention, which can generally be differentiated by two factors: the nature of the filter and the point at which the filter is applied to stimuli from the environment.

A model proposed by Broadbent in 1958 suggests that information is filtered as soon as it is registered at the sensory level. That is to say that the mental faculty that perceives sounds determines which of these sounds merits attention before the information is passed to the remainder of the brain. In essence, the ears (not merely the organs but the parts of the brain that receive and process the sensory input) decide what we hear and the eyes decide what we see. This theory is generally supported by the observation that the more intense signals (louder noises, more vivid colors) command attention, distracting us from more subtle ones.

A separate theory (Treusman 1960) suggests that filtration occurs later: the cognitive faculty attempts to make sense of the chaos of stimuli, and selects which stimuli receive attention. Consider an experiment in which two audio messages had an overlapping phrase - and it's at this point that attention can be shifted from one to the other. The synchronization need not be perfect: participants' attention was observed to shift even if the overlapping phrase was 1.5 to 4.5 seconds after the initial one (depending on whether the shift favored the attended message or the unattended one).

Further, experimentation with bilingual subjects suggest it is not the exact words of the message, but their meaning, that can elicit a shift. As such, it is clearly not the perception of a sound that determines how attention is focused, but the meaning of the words, which is processed later and in a separate part of the brain.

This suggests a three-stage model of perception and attention:

  1. A stimulus is detected and isolated: we consider the volume, pitch, and other qualities of a voice to identify it as a single stimulus
  2. We recognize whether the stimulus has a pattern that signifies meaning, such as speech or music
  3. We interpret the meaning of the stimulus in order to decide (consciously or unconsciously) whether it merits attention

It's suggested that even when a stimulus does not pass a test (a sound does not have a meaningful pattern), it is not discarded, but passed along as a "weakened version" relative to other stimuli that satisfy the conditions of the test.

Yet another theory (Deutsch 1963) suggests that filtering happens even later - that all of the steps above are satisfied before the decision is made whether to give attention to a stimulus. That is to say we perceive, recognize, identify, and understand the meaning of a stimulus, and then decide whether to give attention to it.

Additional theories follow in a similar vein. There is in general an agreement in the order in which sensory data is perceived, recognized, and analyzed for significance, but the precise moment in which the decision is made to ignore some stimuli while giving attention to other remains the topic of some debate.

Resource Allocation Theories

More recent theories have moved away from ignore/attend filters toward the notion that the mind attempts to allocate limited resources, observing that individuals who attempt to perform multiple tasks simultaneously shift attention from one to the other.

The basic model suggests that the mind entertains multiple modalities, and shift attention among stimuli depending on the modality. This functions best when the modalities of the two tasks are significantly different: a person can focus on reading while instrumental music is playing, but their ability to keep stimuli separate wanes when they are listening to music with lyrics or a news broadcast, because processing language is a common factor in both tasks.

This theory has been severely criticized, largely on account of its vague and general nature. It's also been suggested that theories related to filtering already explain this phenomenon, and in more granular detail - but it must be conceded that the additional-resource theory fills a gap in filtering theories, in that it explains why certain stimuli are considered to be significant.

Additionally, the difficulty of a task, including the degree to which it has been automated, also impacts the degree to which attention is required. For example, a person driving on a highway in light traffic may listen to the radio while doing so, but when traffic becomes congested or the weather turns foul, they turn off the radio to give better attention to the task of driving.

Additional Considerations

The author finds the current models of attention "too simplistic and mechanistic to explain the complexities of attention." The phenomenon is influenced by many factors:

Thus, while research has provided many insights into attention, we do not yet have a comprehensive understanding of it.

There's a mention of Stroop (1925) experiments that mismatch the name of a color with the color of ink in which the word is printed, demonstrating that it is difficult for the mind to control which stimulus takes precedence. The difficulty comes from attempting to give attention to a specific stimuli when a task (reading or color recognition) has been automated. A subject taking a Stroop test may be attentive - but attentive to what?

Divided Attention

Divided attention differs from selected attention in that it theorizes that subjects are capable of giving attention to multiple things at the same time, instead of alternating their attention between them.

Research into this phenomenon (Neisser 1975) has not been supportive. Participants were shown two activities on a split screen and press a button when specific events occurred. When told to watch one and ignore the other, their performance was accurate; when told to watch both, their performance was poor; and when the videos were synched to ensure the target events occurred at the same time, it was even worse. Even with repetition and practice, participants were unable to accurately observe both at once.

Additional research the following year tasked individuals with performing two activities at once, and showed that the speed an accuracy of simultaneous performance was "quite poor," though it was also shown that when one of the tasks involved automatic processing and the other required attention, there was some improvement in performance. (EN: three or four other experiments are detailed, all to the same net effect.)

"Driving while distracted" is an example of the problems of attempting to perform multiple tasks at the same time. A study of 2700 accidents in Virginia in 2002 indicated that distractions were at cause in 97% of all accidents (62% occurred within the vehicle and 35% occurred outside of it), with only 3% being attributed to other causes (weather conditions, equipment failure, etc.)

Consciousness of Complex Mental Processes

It is generally believed that people do not have conscious access to very simple mental processes: a person can theorize the way in which they differentiate an uppercase letter from a lowercase one, but in reality the recognition is virtually instantaneous. This begs the question of where the line is drawn in terms of when conscious mental processes are engaged in a task.

Some espouse the view that people have very good access to their mental processes at a very low level: the decision of how to move the pieces at a game of chess, or adding together two numbers (more than single digits) causes people to engage their conscious mental faculty.

By other views, it is believed that access to mental processes are not quite so good - that, in effect, we jump to a conclusion on an unconscious level and then justify it by means of reasoning after the fact. This is particularly true of consumer behavior, in which an individual may choose one brand of product over another without any apparent deliberation, and when asked about their mental processes afterward, they confabulate, having only a vague idea of how them made the decision. The essence of the second view is that people do not have conscious access to their though processes in real time, and very little understanding of them after the fact.

The author also gives the example of the parlor trick of asking people to try not to think of something you have named: "do not think about an elephant" conjures the image of it to mind. For the same reason we have difficulty trying not to dwell on people or situations we find vexatious. The implication is that our though processes react to stimuli, and are not voluntarily switched on or off.

The phenomenon of change blindness is mentioned - which implies that once attention is given to something specific, it is taken away from any extraneous factor. In one particularly bizarre study (Simons and Levin 1997), and experiment was done in which a proctor would approach someone on the street and ask for directions. In the middle of their giving directions, a couple of workmen would pas between them carrying a door and, when the workmen passed, a different person would be standing there. It is claimed that only about half of bystanders continued giving directions as if they did not notice that they were confronted with a completely different person.

(EN: I found this a bit incredible, and looked it up online, even saw a video of such an experiment ... and it was mindblowing. They swapped in a person of the same general age and gender, but dressed entirely differently, and the subject carried on, completely oblivious to the change.)

Attention Deficit Hyperactivity Disorder (ADHD)

This condition, first diagnosed in 1845, is expected to affect 3% to 5% of the population, which causes people to have difficulties focusing their attention on specific stimuli to the exclusion of others, in the way unaffected minds do.

The condition ahs gained a great deal of popularity since the discovery of a pharmaceutical treatment, and its causes are unclear: maternal smoking and drinking have been cited, brain injury during childbirth, food additives, and video games have all be statistically linked.

The fundamental characteristics of the disorder are the subjects are easily distracted by sights and sounds and, even without distraction, are unable to place sufficient attention on details that are before them.

(EN: This continues for a bit, but largely focuses on the pathology of the disorder and makes no connection to the phenomenon of attention otherwise.)

Neuroscience Approaches to Attention and Consciousness

Neuroscientists have shown great interest in attention, examining activity in the brain to determine its processes, and have come to the conclusion that attention "is neither a property of a single brain area nor of the entire brain." Which is to say they have not come to a firm conclusion about anything at all.

Various researchers have studied attention and found that no specific region of the brain can be specifically ascribed the responsibility for attentiveness. They have correlated damage and industry of specific parts of the brain to perception - e.g., damage to the right occipital lobe corresponds to loss of vision to the left eye.

Posner (1995) identified an anterior attention system within the frontal lobe and a posterior attention system in the parietal, which show increase activity in subjects performing tasks that require attention. The anterior system seems most active in maintaining attentiveness to the environment and the posterior is more active in visuospatioal attention.

But attention can also be seen to increase activity in the various parts of the brain in the relevant visual, auditor, and motor cortexes that are engaged in a given task. (EN: I recall reading elsewhere that even imagining the appearance of an object creates activity in the visual cortex, which would suggest that these sectors in the brain are not merely responding to external stimuli.)

It's noted that distractor stimuli also cause activity in regions of the brain associated to attention, when the subject is engaged in the performance of a task and does not report even having been aware of them. That is to say that the brain is paying attention to things to some degree, even if only to recognize that they do not require attention.

In addition to studying the activity in the brain of normal patients, neuroscientists have also studied the activity in damaged brains, to identify attention deficits related to lesions or irregular blood flow. From these studies it seems that overall attention deficits are linked to the frontal lobe and basal ganglia, with visual deficits specifically linked to the posterior parietal cortex and thalamus.

Another approach to understanding the attention process has involved the use of psychoactive drugs, the results of which have suggested that the reticular activating system is linked strongly to arousal, habituation, and dishabituation as well as the orienting reflex, which causes an individual to respond to an event by changing the orientation of the body (turning one's head toward a loud sound or a flash of light).

Perception, Attention, and Consciousness

The author calls specific attention to the work of Anthony Marcel, who proposed a model describing how sensations and cognitive processes that occur outside of conscious awareness may influence conscious perception.

That is to say that even though stimuli occur outside of conscious awareness, the human mind continually attempts to make sense of the chaos, ignoring some stimuli while attending to others, and that the unconscious processing creates a proclivity or sensitivity in conscious awareness to certain stimuli. Further, that when there is a convergence among stimuli that are unconsciously processed, conscious awareness is triggered.

Tat is to say that a person engaged in reading a book may be unaware of the faint aroma of smoke, a dim flickering light on the edge of their vision, and a light rustling noise in the distance, until the unconscious mind puts all of these stimuli together and cause the subject to be aware of a fire. And only then may the subject turn away from his book to see if there is an emergency situation.

At the same time, sensory data and cognitive processes that do not reach our awareness nonetheless exert influence on the way we think and how we perform cognitive tasks. Given the same example, an individual who is not conscious of the smell of smoke may still behave in a manner that reflects some level of panic, even if he is not consciously aware of the reason he should feel that way.

(EN: This might explain why we seek sensory deprivation at times when we wish to focus the mind on a given task - to turn of the radio while driving, or to go to a quiet place in order to read.)

Key Themes

The author identifies three key themes for this chapter:

  1. The brain contains various structures and systems that generate the processes that contribute to attention, even though the precise relationship between processes and attention are not presently clear.
  2. While there is a link between biology and behavior, it is tenuous in consideration of attention. That is, "biology does not appear to be generate the behavior"
  3. In terms of attention, the environment of the laboratory and the design of an experiment have a pronounced impact on the outcomes. In this regard, it is clear that tests designed to evoke a certain response are highly successful at doing so, and there is cause to be suspicions of their applicability in the wild.
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