Paying Attention

 Attention

●       Attention captured the interest of William James in the late 1800s.

●       James (1890/1983) anticipated the recent writings of investigators studying attention when he argued that only one system or process of conception can go on at a time very easily; to do two or more things at once, he believed, required that the processes be habitual.

●      James’s (1890/1983) description of attention,

●      “Everyone knows what attention is. It is the taking possession by the mind, in clear and vivid form, of one out of what seem several simultaneously possible objects or trains of thought. 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 which in French is called distraction and Zerstreutheit in German”

●      The essence of attention is the act of selection (arguably) borne from a fundamental limit with respect to our information processing capacity

●      Many cognitive psychologists consider humans to be limited capacity information processors. This requires some form of selection – withdrawal from some things in order to deal more effectively with others.

Selective Attention

Selective attention refers to the fact that we usually focus our attention on one or a few tasks or events at any given time.

How do cognitive psychologists study what information people process about things to which they are not paying attention?

solution is well known to cognitive psychologists. it is known as the dichotic listening task. It works like this: A person listens to an audiotape over a set of headphones. On the tape are different messages, recorded so as to be heard simultaneously in opposite ears. EG BROADBENT

Sometimes the tapes are recorded so that both messages are heard in both ears—called binaural presentation

Findings

●      Cherry (1953) demonstrated in a classic study that people can, with few errors, shadow a message spoken at a normal to rapid rate. When researchers later questioned these participants about the material in the unattended message, they could nearly always report accurately whether the message contained speech or noise and, if speech, whether the voice was that of a man or a woman.

●      When the unattended message consisted of speech played backward, some participants reported noticing that some aspect of the message, which they assumed to be normal speech, was vaguely odd.

●       Participants could not recall the content of the unattended message or the language in which it was spoken. In one variation of the procedure, the language of the unattended message was changed from English to German, but participants apparently did not notice the switch.

●      Participants in another experiment (Moray, 1959) heard prose in the attended message and a short list of simple words in the unattended message. They failed to recognize the occurrence of most words in the unattended message, even though the list had been repeated 35 times!

 Broadbent/Filter theory (Wrong theory)

●      His model is referred to as an “Early Selection” model because it posits that attentional selection operates very early in the stream of processing, before the observer actually knows what the information is and that this selection is based only on physical characteristics like where the information is coming from, its pitch, volume, colour, brightness, and so on.

●      Critically then, selection occurs early, before any meaning information, also known as semantics is processed from the item.

Broadbent’s experiment - 2 messages are played that are different from one another , one in left ear and one in right. Participants are instructed to pay attention to one message of the two.

Results of the exp.

●      What Broadbent found was when observers in his experiments were doing a good job of shadowing the message they were supposed to paying attention to,

●      let’s say it was the left ear, they noticed virtually nothing at all about the message being played in the right ear.

●      They might notice the volume of the message or the pitch of that message, but they could not accurately say what was being spoken.

●       That was true even if the same word was repeated again, and again, and again in that other ear.

●      They also were unable to notice if the language spoken in that second ear was different from the language in the ear they were shadowing.

Conclusion

Broadbent argued then, that attentional selection was selecting material from the appropriate channel, allowing it to be processed to the point where one can understand that information.

Moreover, he said that information in the unselected, unattended channel was not being processed beyond its basic physical features, and certainly not enough to allow the observer to know what that information was or even what language that information was being conveyed in.

 problems with Broadbent’s Filter Theory

Have you ever been in a crowded, loud party and been struggling to carry on a conversation with a friend?

You find yourself concentrating on his or her words so that you can hear them over the background noise. All of a sudden, you hear someone mention your name- not calling out to you- just in regular conversation. According to Broadbent, that should not occur, because you had not selected that information.

 Instead, you were intently processing your own conversation and therefore you should not have “known” that it was your name that was being spoken

This phenomenon is known as the cocktail party effect ( described by Moray in 1959.)

Using a dichotic listening task, Moray showed that people often did notice their own names

when their own names were played in the unattended channel, even though they were keeping up with the difficult task of shadowing information in the attended channel. Again, according to Broadbent, that should not have occurred.

Alternative explanation for the cocktail party effect.

●       the shadowing task does not always take 100% of one’s attention. Therefore, attention occasionally lapses and shifts to the unattended message. During these lapses, name recognition occurs.

●      Treisman (1960) discovered a phenomenon that argues against this alternative interpretation of the cocktail party effect.

●      She played participants two distinct messages, each presented to a different ear, and asked the participants to shadow one of them. At a certain point in the middle of the messages, the content of the first message and the second message was switched so that the second continued the story-line of the first and vice versa (see Figure 4-3). Immediately after the two messages “switched ears,” many participants repeated one or two words from the “unattended ear.”

●      If participants processed the unattended message only when their attentional filter “lapsed,” it would be very difficult to explain why these lapses always occurred at the point when the messages switched ears.

●      To explain this result, Treisman reasoned that participants must be basing their selection of which message to attend to at least in part on the meaning of the message—a possibility that filter theory does not allow for

The issue of whether information from the unattended channel can be recognized was taken up by Wood and Cowan (1995).

●      In one experiment, they had 168 undergraduate participants perform a dichotic listening task. Two of the groups shadowed an excerpt from The Grapes of Wrath (read very quickly, at a rate of 175 words per minute) in the attended channel (always presented to the right ear) and were also presented with an excerpt from 2001: A Space Odyssey in the unattended channel, always presented to the left ear.

●      Five minutes into the task, the speech in the unattended channel switched to backward speech for 30 seconds. Previous experiments had established that under these conditions, roughly half of the participants would notice the switch and half would not.

●      The two groups differed only in how long the “normal” speech was presented after the backward speech: two and a half minutes for one group; one and a half minutes for the other. A third, control group of participants heard an unattended message with no backward speech.

●      Wood and Cowan (1995) first asked whether the people who noticed the backward speech in the unattended message showed a disruption in their shadowing of the attended message.

●      In other words, if they processed information in the unattended message, did this processing have a cost to their performance on the main task? The answer was a clear yes

●       Wood and Cowan counted the percentage of errors made in shadowing and noted that the percentage rose to a peak during the 30 seconds of the backward-speech presentation.

●      The effect was especially dramatic for those people who reported noticing the backward speech. Control participants, who were never presented with backward speech, showed no rise in their shadowing errors, nor did most of the participants who did not report noticing the backward speech

What caused the shift in attention to the backward speech?

Wood and Cowan (1995) analysed shadowing errors by 5-second intervals for the 30 seconds preceding, during, and following the backward-speech segment

●       These findings, show that control participants and participants who did not notice the backward speech made no more errors over the time studied.

●       However, participants who did report hearing backward speech made noticeably more errors, which peaked 10 to 20 seconds after the backward speech began

Treisman /Attenuation Theory or Leaky Filter Model

Work by Anne Treisman further underscored this problem with Broadbent’s model by showing that when shadowing we sometimes do pick up information from the unattended channel, but only when that information is important to us.

(Instead of considering unattended messages completely blocked before they could be processed for meaning )

So for instance, it could be our name, or a warning word like fire, or some other information that’s relevant to the context of the information we’re currently trying to process.

Hers, like Broadbent’s, is an early selection model and states that there is almost no processing of information from the unattended channel.

She explained this idea as follows.

●      Incoming messages are subjected to three kinds of analysis.

a.     In the first, the message’s physical properties, such as pitch or loudness, are analyzed.

b.     The second analysis is linguistic, a process of parsing the message into syllables and words.

c.     The third kind of analysis is semantic, processing the meaning of the message. Some meaningful units (such as words or phrases) tend to be processed quite easily. Words that have subjective importance (such as your name) or that signal danger (“Fire!” “Watch out!”) have permanently lowered thresholds; that is, they are recognizable even at low volumes. You might have noticed yourself that it is hard to hear something whispered behind you, although you might recognize your name in whatever is being whispered

●      Only a few words have permanently lowered thresholds. However, the context of a word in a message can temporarily lower its threshold. If a person hears “The dog chased the...,” the word cat is primed—that is, especially ready

●      Even if the word cat were to occur in the unattended channel, little effort would be needed to hear and process it. This explains why people in Treisman’s experiment “switched ears”

According to Treisman (1964), people process only as much as is necessary to separate the attended from the unattended message.

●       If the two messages differ in physical characteristics, then we process both messages only to this level and easily reject the unattended message.

●      If the two messages differ only semantically, we process both through the level of meaning and select which message to attend to based on this analysis.

●      Processing for meaning takes more effort, however, so we do this kind of analysis only when necessary.

. Messages not attended to are not completely blocked but rather weakened in much the way that turning down the volume weakens an audio signal from a stereo

 contrasts here between attenuation theory and filter theory

●      Attenuation theory allows for many different kinds of analyses of all messages, whereas filter theory allows for only one.

●      Filter theory holds that unattended messages, once processed for physical characteristics, are discarded and fully blocked; attenuation theory holds that unattended messages are weakened but the information they contain is still available.

The only information from the unattended channel that will be become processed is information that ultimately leaks through the filter and that’s because that information has some kind of special value to us

Corteen and Wood

 paired select Canadian city names, such as Vancouver, Montreal, Regina and Winnipeg, with electric shocks until the mere mention of these city names produced a fear response that could be measured in the observers’ galvanic skin response or GSR.

 A GSR measures changes in respiration, perspiration, and so forth that can be picked up on the skin.

●      Corteen and Wood then had their observers participate in a dichotic listening task and asked them to shadow a message.

●      Unbeknownst to the observers, Corteen and Wood played the names of the Canadian cities in the unattended channel.

●      Despite the fact that the observers did not report hearing the city names, they produced a GSR when the names were played, indicating that they had indeed processed this “unattended” information

Fascinatingly, the observers also produced GSRs when these new city names were presented, despite the fact that they were not aware of having heard them.

This clearly indicates that these items were processed to the level of semantics, as only then can one know that Toronto is indeed a Canadian city.

This result provided a major challenge to early selection theories, as it would suggest that perhaps all information in the unattended channel is processed all the way to the level of meaning or semantics, even if the observer never becomes aware of that.

Deutsch/Late-Selection Theory

●      Broadbent’s (1958) filter theory holds that no information about the meaning of an unattended message gets through the filter to be retained for future use.

●       Treisman’s (1964) attenuation theory allows for some information about meaning to get through to conscious awareness.

●      Deutsch and Deutsch (1963) proposed a theory, called the late-selection theory, which goes even further

Results like those of Corteen and Woods led to the development of a late selection model of attention, also known as the Deutsch-Norman model.

This model posits that all information—whether we are trying to attend to it or not- is processed until the point at which we can access its meaning in long term memory. Selective attention then operates at this late stage in order to direct our awareness or to guide our response to that information.

So, even if we aren’t aware of information, it is possible that we have processed it and have actually activated its representation in memory and that it can, in fact, influence our behavior.

Alternate definition -all messages are routinely processed for at least some aspects of meaning. Attentional selection occurs after this routine processing, very late relative to the two earlier models

How much processing occurs?

According to Pashler’s (1988) interpretation of late-selection theory, at a minimum, the recognition of familiar objects of stimuli would be achieved:

“Recognition of familiar objects proceeds unselectively and without any capacity limitations. One cannot voluntarily choose to identify or recognize something, according to these theorists. Whether there is just one sensory input or many does not affect the extent to which stimuli are analyzed or the timing of such analyses”

Note

●      filter theory hypothesizes a bottleneck—a point at which the processes a person can bring to bear on information are greatly limited—at the filter.

●      Late-selection theory also describes a bottleneck but locates it later in the processing, after certain aspects of the meaning have been extracted. All material is processed up to this point, and information judged to be most “important” is elaborated more fully. This elaborated material is more likely to be retained; unelaborated material is forgotten.

●      A message’s “importance” depends on many factors, including its context and the personal significance of certain kinds of content (such as your name).

●      Also relevant is the observer’s level of alertness: At low levels of alertness (such as when we are asleep), only very important messages (such as the sound of our newborn’s cry) capture attention.

●      At higher levels of alertness, less important messages (such as the sound of a television program) can be processed.

●      Generally, the attentional system functions to determine which of the incoming messages is the most important; this message is the one to which the observer will respond.

How well does the evidence for late-selection theory measure up?

Different theorists take different positions on this issue.

●      Pashler (1998) argues that the bulk of the evidence suggests it is undeniably true that information in the unattended channel sometimes receives some processing for meaning.

●      At the same time, it appears true that most results thought to demonstrate late selection could be explained in terms of either attentional lapses (to the attended message) or special cases of particularly salient or important stimuli grabbing attention.

●      In any event, it seems unlikely that unattended messages are processed for meaning to the same degree as are attended messages.

Attention, Capacity, and Mental Effort/ Kanehenman Budget Model

Daniel Kahneman viewed attention as a set of cognitive processes for categorizing and recognizing stimuli. The more complex the stimulus, the harder the processing, and therefore the more attentional resources are required.

People have some control over where they direct their mental resources, however: They can often choose what to focus on and where to allocate their attentional resource.

Essentially, this model depicts the allocation of mental resources to various cognitive tasks. An analogy could be made to a student managing a monthly budget.

The student needs to decide how much money can be spent on food, entertainment, and perhaps a gym membership, in order to have enough left over to pay rent, tuition, and to buy books. In the case of Kahneman’s model, the individual “spends”.s” mental capacity on one or more of several different tasks.

Many factors influence this allocation of capacity, which itself depends on the extent and type of mental resources available. The availability of mental resources, in turn, is affected by the overall level of arousal, or state of alertness.

●      Kahneman (1973) argued that one effect of being aroused is that more cognitive resources are available to devote to various tasks. Paradoxically, however, the level of arousal also depends on a task’s difficulty.

●      This means we are less aroused while performing easy tasks, such as adding 2 and 2, than we are when performing more difficult tasks, such as multiplying a social insurance number by pi.

●      We therefore bring fewer cognitive resources to easy tasks, which, fortunately, require fewer resources to complete. Arousal thus affects our capacity (the sum total of our mental resources) for tasks.

●      But the model still needs to specify how we allocate our resources to all the cognitive tasks that confront us.

●      Essentially, this model predicts that we pay more attention to things we are interested in, are in the mood for, or have judged important. For example, opera lovers listen carefully during an operatic performance, concentrating on nuances of the performance. People less interested in opera may sometimes have a hard time even staying awake.

●      attention is part of what the layperson would call “mental effort.” The more effort expended, the more attention we are using

●      Effort is only one factor that influences performance on a task, however. Greater effort or concentration results in better performance on some task

●       On some other tasks, one cannot do better no matter how hard one tries. An example is trying to detect a dim light or a soft sound in a bright and noisy room. Even if you concentrate as hard as you can on such a task, your vigilance still may not help you detect the stimulus. Performance on this task is said to be data limited, meaning that it depends entirely on the quality of the incoming data, not on mental effort or concentration

●     

Automaticity and Practice

We say a process or a behaviour becomes more automatic as it requires fewer attentional resources to perform. This typically occurs with practice.

In addition to practice leading to greater automaticity and the need for fewer resources to complete a task, it can sometimes have an unwanted side effect.

That is, sometimes the more automatic behaviour becomes so automatic that we simply cannot prevent it from happening, even when we don’t want to do it, and when doing it actually impairs our ability to do the thing that we’re trying to do.

 Eg- stroop test

●      It is hypothesized that reading is such an automatic process in expert readers that one cannot prevent it, even when its effects are deleterious on what we intend to do. This in fact is what produces Stroop interference

●      kindergartener, will find that they are not at all troubled by Stroop interference, or at least not like you are.hey simply are not yet expert readers performing an automatic behaviour.

●      For them, reading is a controlled behaviour.

●      If you have a friend who is just learning a new language, you might also find that in the new language, these individuals do not yet produce Stroop interference,

●       although they would produce Stroop interference in their native language.

●      Beginning readers and readers learning a brand new language are not yet expert readers performing an automatic behaviour. For them, reading is still a controlled process.

Schneider and Shiffrin

They examined automatic processing of information under well-controlled laboratory conditions. They asked participants to search for certain targets, either letters or numbers, in different arrays of letters or numbers called frames. For example, a participant might be asked to search for the target J in an array of four letters: B M K T.

Previous work had suggested that when people search for targets of one type (such as numbers) in an array of a different type (such as letters), the task is easy

●      Numbers against a background of letters seem to “pop out” automatically. In fact, the number of nontarget characters in an array, called distractors, makes little difference if the distractors are of a different type from the targets.

●       So finding a J among the stimuli 1, 6, 3, J, 2 should be about as easy as finding a J among the stimuli 1, J, 3.

●      Finding a specific letter against a background of other letters seems much harder. So searching for J among the stimuli R J T is easier than searching for the J among the stimuli G K J L T, both of which are more difficult than finding a J amongst digits.

●      In other words, when the target and the distractors are of the same type, the number of distractors does make a difference.

Schneider and Shiffrin (1977) had two conditions in their experiment.

●      In the varied-mapping condition, the set of target letters or numbers, called the memory set, consisted of one or more letters or numbers, and the stimuli in each frame were also letters or numbers. Targets in one trial could become distractors in subsequent trials. So a participant might search for a J on one trial, then search for an M on the second trial, with a J distractor included. In this condition, the task was expected to be  hard and to require concentration and effort.

●      In the consistent-mapping condition, the target memory set consisted of numbers and the frame consisted of letters, or vice versa. Stimuli that were targets in one trial were never distractors in other trials. The task in this condition was expected to require less capacity

●      In addition, Schneider and Shiffrin (1977) varied three other factors to manipulate the attentional demands of the task.

○      The first was frame size—that is, the number of letters and numbers presented in each display. This number was always between 1 and 4. Slots not occupied by a letter or number contained a random dot pattern.

○      Second was the frame time—that is, the length of time each array was displayed. This varied from approximately 20 milliseconds to 800 millisecond.

○       The last variable manipulated was the memory set—that is, the number of targets the participant was asked to look for in each trial (for example, find a J versus find a J, M, T, or R)

Schneider and Shiffrin (1977) explained these results by distinguishing between two kinds of processing.

 Automatic processing, they asserted, is used for easy tasks and with familiar items. It operates in parallel (meaning it can operate simultaneously with other processes) and does not strain capacity limitations. This kind of processing is done in the consistent-mapping condition: Because the targets “popped out” from the background, little effort or concentration was required. That searching for four targets was as easy as searching for one illustrates the parallel nature of this kind of processing: Several searches can be conducted simultaneously

●      Schneider and Shiffrin (1977) dubbed the second kind controlled processing. Controlled processing is used for difficult tasks and ones that involve unfamiliar processes.

●      It usually operates serially (with one set of information processed at a time), requires attention, is capacity limited, and is under conscious control.

●      Controlled processing occurred in the varied-mapping condition (where targets and distractors could alternate across different trials). More generally, controlled processing is what we use with nonroutine or unfamiliar tasks

controlled vs. automatic behaviour

●       Controlled behaviours are said to be those that we undertake serially, or one at a time, and that require attention.

●      Moreover, they are said to be capacity limited, meaning that if we attempt a second process that also requires attention while we’re trying to perform the first, at some point we’ll not have enough resources to perform both—we’ll simply run out of fuel.

●      Finally, controlled processes are under our conscious control.

●      automatic processing occurs without our intention

●       we often are not aware of doing it. It does not require attention, so it in itself does not interfere with other mental activities, although the result of such automatic processing might, as we just saw as in the case of reading in the Stroop task

●      Finally, automatic processing can occur in parallel with, or along with, other processes and they do not constrain capacity limitations, because they require little or no attention at all.

DIVIDED ATTENTION

If attention is a flexible system for allocating resources, and if tasks differ in the amount of attention they require, then people should be able to learn to perform two tasks at once.

Dual-Task Performance

Spelke, Hirst, and Neisser (1976) examined this question in a clever and demanding laboratory study.

Two Cornell University students were recruited as participants. Five days a week, for 17 weeks, working in 1 hour sessions, these students learned to write words dictated while they read short stories. Their reading comprehension was periodically tested.

After 6 weeks of practice, their reading rates  approached their normal speeds. Also by the end of 6 weeks, their scores on the reading comprehension tests were comparable whether they were only reading stories (and thus presumably giving the reading task their full attention) or reading stories while writing down dictated words.

 Further investigation revealed that participants could also categorize the dictated words by meaning and could discover relations among the words without sacrificing reading speed or comprehension

Many psychologists were surprised that the participants in this study could process information about meaning without conscious attention, and some offered alternative explanations for the findings.

One hypothesis is that participants alternated their attention between the two tasks, attending first to the story, then to the dictation, then back to the story, and so on.

●      Although this possibility was not directly tested, the authors argued that the fact the participants’ reading speeds were comparable whether or not they were taking dictation suggests that if they were alternating their attention, they were doing so without any measurable lag.

●      Hirst, Spelke, Reaves, Caharack, and Neisser (1980) found evidence against this alternation hypothesis.

●      Their participants were trained in ways similar to those used by Spelke et al. (1976). All participants copied dictated words while reading. Some participants read short stories, presumably containing some redundant material and therefore requiring relatively little attention. Other participants read encyclopedia articles, thought to contain less redundant material and thus to require more concentration.

●      After they reached normal reading speeds and reading comprehension during dictation, the participants’ tasks were switched: Those who had been reading short stories were now given encyclopedia articles, and those trained using encyclopedia articles now read short stories.

●      Six of the seven participants performed comparably with the new reading material, indicating that the participants were probably not alternating their attention between the two tasks. If they were, then learning to take dictation while reading short stories should not transfer well to doing so while reading encyclopedia articles.

●      A second possible explanation for participants’ ability to learn to do two tasks at once is that one of the two tasks (for example, the dictation task) is being performed automatically

●      According to one of Posner and Snyder’s (1975) criteria for automaticity—that processing not interfere with other mental activity—taking dictation in this study might be considered automatic

●      However, participants were clearly aware that words were being dictated, and they typically recognized about 80% of the dictated words on tests immediately following trials.

●      Moreover, participants clearly intended to copy the dictated words. Therefore, taking dictation does not meet Posner and Snyder’s last two criteria: lack of intention and lack of conscious awareness.

●      Hirst and colleagues (1980) also offered evidence against the possibility that one task becomes automatized. Participants trained to copy complete sentences while reading were able to comprehend and recall those sentences, suggesting that the participants had processed the dictation task for meaning. This in turn suggests they paid at least some attention to the dictation task, given that most psychologists believe automatic processing occurs without comprehension

●      A third explanation for how participants were able to perform two tasks at once, which Hirst and colleagues (1980) favoured, is that the participants learned to combine two separate tasks: reading and taking dictation.

○      That is, practice with these two specific tasks caused the participants to perform the tasks differently from the way they did them at first.

○      This implies that if either one of these tasks were combined with a third (such as shadowing prose), additional practice would be needed before the two tasks could be done together efficiently.

○       Practice thus appears to play an enormous role in performance and is one important determinant of how much attention any task requires

The Psychological Refractory Period (PRP)

Pashler (1993) reported on studies from his and others’ laboratories that examined the issue of doing two things at once in greater depth.

The participant is asked to work on two tasks.

1. The first is a tone choice response task, in which on each trial the participant is presented with either a low- or a high-pitched tone and is instructed to respond “low” or “high” as quickly as possible. Response times are recorded, and the participant is often given feedback regarding speed and accuracy.

2. The second task involves visual presentation of a letter, and the participant is instructed to press one of several response keys that correspond to the letter presented.

The interval between the presentation of the tone (S1 in the diagram) and the letter (S2 in the diagram) is systematically varied.

●      At long intervals participants show no interference and appear to perform the two tasks successively, finishing their response to the first task before beginning to work on the second.

●      However, as the interval between the presentation of S1 and S2 gets shorter and shorter, the time to complete the second task gets longer and longer.

●      The hypothesized explanation is that while the participant is working on the first task, he cannot devote any attention to make progress on the second.

●      short intervals between the presentation of S1 and S2, called the psychological refractory period, or PRP

, Pashler considered three distinct possibilities:

●      at the stage of perception of the stimulus (A),

●      at the stage of making a response (C),

●       or at the stage in which a response is selected or chosen (B).

●      Perceptual Processing: (A)

●      Response Selection: (B)

●      Response Execution: (C)

Experimental evidence pointed to the bottleneck happening at (B)

 In fact, the work of Pashler (1993) and his colleagues supports the theory of Welford (1952), who argued for this last possibility (B) and who coined the term psychological refractory period.

Pashler (1993) also found evidence that retrieving information from memory caused a bottleneck and disrupted attention to the second task.

Canadian researchers Mike Tombu and Pierre Jolicoeur have recently offered an alternative to the bottleneck account of the psychological refractory period,

●       Rather than posit that attention must be divided in an all-or-none fashion between two tasks, Tombu and Jolicoeur argued that it can be shared in a more flexible manner.

●      That is, while performing an attention-demanding phase of task 1, people can choose to allocate some attention to a demanding phase of a second task

Tombu and Jolicoeur’s account predicts that when people choose to share some attention between the two tasks performance on the first task will be impaired relative to when all attention is devoted to it. Research from their lab supports this capacity-sharing model

The Attention Hypothesis of Automatization/ Gordon Logan and Joseph Etherton

attention hypothesis of automatization- states that attention is needed during the practice phase of a task and determines what gets learned during practice. Attention also determines what will be remembered from the practice.

 People will learn about the things they attend to and they will not learn much about the things they do not attend to”

Specifically, Logan and colleagues argued that attention affects what information gets encoded into a memory and what information is later retrieved

●      In a series of experiments, Logan and Etherton (1994) presented university student participants with a series of two-word displays and asked them to detect particular target words (for example, words that named metals) as fast as possible.

●      For some participants, the word pairs remained constant over trials; for example, if the words steel and Canada were paired on one trial, then neither word ever appeared with any other word on subsequent trials.

●      Other participants saw word pairs that varied from trial to trial, such as steel with Canada on one trial and steel with broccoli on another. The question was: Would participants in the first condition gain an advantage in performance because the words were consistently paired? 

●      The answer was yes, but only when the specifics of the target detection task forced the participants to pay attention to both words in the display.

●      If, for example, the experimenters coloured one of the two words green and asked participants only to decide whether the green word in a stimulus display was a target word on each trial, then participants did not gain an advantage from consistent pairings of words and indeed later recalled fewer of the distractor words

Real World Applications

University of Utah researchers David Strayer and William Johnston asked their participants to perform a pursuit tracking task

 In this task observers were seated in front of a computer monitor and were asked to keep the computer’s cursor on a moving target.

Periodically while the cursor was moving, it turned red, in which case the participants were asked to immediately press a button, or it turned green, in which case they could ignore the colour change and continue tracking

This light change manipulation was modeled after the need for a driver to brake in response to a red light.

Participants were asked to perform this tracking and colour monitoring task alone,

in the single task condition in order to become proficient at it.

 After they were very good at this task they were then asked to perform the same tracking and monitoring task in one of two dual task conditions.

 specifically in this case, tracking and monitoring was done either while the participant listened to a radio broadcast, or while the participant had to maintain a telephone conversation with an experimental confederate

The results indicated that many more errors, in the form of missed red lights, were made in the dual task condition than in the single task condition, but only when the dual task condition required participants to maintain a cell phone conversation with a confederate

Listening to a radio broadcast did not affect performance in the same way. Even when participants in the cell phone condition did respond correctly to the red lights, they did so much more slowly than did participants who merely listened to a radio broadcast.

Furthermore, research by Strayer and Johnston and by others makes it clear that the difficulty is not dictated by the use of one’s hands. Therefore requiring individuals to use hands-free phones will not solve what is actually an attentional problem

Interestingly, Strayer and Johnston also comment on while speaking on a cell phone is dangerous, whereas driving while carrying on a conversation with a passenger is not so dangerous.

A passenger in your car will likely notice changes in driving conditions, more traffic, lots of pedestrians, a coming storm, that someone not present in the car just won’t be able to find. In other words, a passenger likely shares joint attention with the driver and adjusts the expectations of the conversation accordingly. Somebody who is far away on a cell phone doesn’t have that same opportunity.

SPATIAL ATTENTION

Attention plays a large role in how efficient you are in your visual search, and in the types of things that aid and impair your performance,

Spatial Cueing(Posner and colleagues)

●      Observers were told  to fixate on a plus sign in the centre of the screen.

●      An arrow cue then appeared above the fixation, and it pointed either to the right, to the left, or had two heads (one pointing left and one pointing right).

●      Observers were told to move attention, but not their eyes, in the direction indicated by the one-headed arrow cue. In the case of a two-headed cue, they were told to leave attention (and their eyes) at the fixation sign.

●      A simple target (a square) then appeared on the screen, and observers were asked to hit a key when they detected the target. On 80% of trials with a one-headed cue, the target appeared in the same location indicated by the cue; this was called a valid trial.

●      On 20% of trials with a one-headed cue,  the target appeared in the location opposite to that indicated by the cue; this was called an invalid trial.

●      Finally, in the case of two-headed cues, targets were equally likely to appear on either side. This was called a neutral trial. Posner and colleagues measured the time it took observers to detect targets in the valid, invalid, and neutral trial conditions.

●      The results indicated that observers were fastest in the validly cued condition and slowest in the invalidly cued condition.

●      Posner and colleagues interpreted these results as showing that performance was facilitated on valid trials (relative to neutral trials), presumably because observers shifted attention to the location of the target prior to its appearance.

●      Likewise, there was an important cost (relative to a neutral trial) to having shifted attention to the wrong location on an invalid trial. From results like these, Posner and colleagues (1980) developed a spotlight metaphor of attention and suggested that, “attention can be likened to a spotlight that enhances the efficiency of detection of events within its beam”

Visual Search

feature integration theory. -general idea is that we perceive objects in two distinct stages.

1. In the first stage, which is preattentive, or automatic, we register features of objects, such as their colour or shape. This allows us to detect or recognize all objects that can be identified on the basis of a single feature, like the blue Z in panel A, without the use of attention.

2. In the second stage, attention allows us to “glue” the features together into a unified object (Tsal, 1989a). This stage is necessary in order to identify complex objects, or to detect objects that share features with other background objects, such as the blue Z in Panel C

Interestingly, in a later study Treisman and Schmidt (1982) showed that when attention is diverted or “overloaded,” participants make “gluing” errors, resulting in what Treisman called illusory conjunctions

In other words, when mentally taxed, people mistakenly combined features in illusory conjunctions

Treisman argued that individual features can be recognized automatically, with little mental effort. What apparently requires mental capacity is the integration of features, the putting together of pieces of information to recognize more complicated objects.

Thus, according to Treisman, perceiving individual features takes little effort or attention, whereas “gluing” features together into coherent objects requires more

Attention is a necessary prerequisite in order to achieve perception of a stimulus can be found in the phenomenon of inattentional blindness.

inattentional blindness-a failure to notice unexpected but perceptible stimuli in a visual scene while one’s attention is focused on something else in the scene.

Change blindness, the inability to notice large changes to scenes when the scene is somehow disrupted

Change blindness has been linked to another phenomenon known as inattentional blindness, the phenomenon of not perceiving a stimulus that might be literally right in front of you, unless you are paying attention to it.

Presumably, we perceive only those events to which we attend, especially if the unexpected event is dissimilar to the focus of our attention, and if our attention is tightly focused somewhere else.

Example the gorilla experiment where two teams of black and white tshirts were passing the ball and you were supposed to follow the ball. You don’t end up noticing the gorilla

NEUROSCIENTIFIC STUDIES OF ATTENTION

Researchers have long suspected the parietal lobe of the brain is active when a person is attending to a stimulus or event, or atleast one such location.

Clinical neurologists have documented the phenomenon of sensory neglect (sometimes called hemineglect) in patients who have parietal lobe damage.

●      These patients often ignore or neglect sensory information located in the visual field opposite the damaged hemisphere. Thus if an area of the right parietal lobe is the damage site (as it often is), the patient overlooks information in the left visual field. This neglect may include, for example, neglecting to wash one side of the face or body, neglecting to brush the teeth on one side of the mouth, or eating from only one side of the plate.

●     

●      Clinical work has established that hemineglect is attentional, rather than sensory (Banich, 1997). Were it simply a sensory deficit, we would expect patients to turn their gaze to the part of the visual field they were missing—in other words, to be aware their visual information is incomplete.

●      Indeed, some patients have just this type of deficit, and they do compensate by just such strategies.

●      In contrast, patients with hemineglect seem unaware of one side of their body and disinclined to try to attend to information from that side. In extreme cases, patients with hemineglect even deny that some of their own limbs belong to them.

parietal lobe is one brain region known to be associated with attention, it is not the only one. Areas of the frontal lobe as well  play a role in people’s ability to select motor responses and develop plan

Networks of Visual Attention

Researchers have identified more than 32 areas of the brain that become active during visual processing of an attended stimulus

Posner and his colleagues used the following cueing task, A participant is seated in front of a visual display, fixating on a central point. On either side of the point are two boxes. On each trial, one box brightens or an arrow appears, indicating on which side of the screen the participant should expect to see the next stimulus.

The purpose of this cue is to encourage the participant to focus his or her attention at a particular location. The participant’s task is to respond as fast as possible when he detects the stimulus. Sometimes no cue is given, and at other times an invalid cue is given, to assess the benefit of having attention focused in either the valid or invalid location

to perform this task a person needs to execute three distinct mental operations.

She first must disengage her attention from wherever it was previously directed. Brain activity in the posterior parietal lobe is heightened during this process.

Once disengaged, attention must be refocused on the spatial location of the new to-be-attended stimulus. Posner and Raichle called this the move operation.

They reported that patients with brain damage in the superior colliculus, a major structure of the midbrain , have difficulty moving their attention from one location to another. Finally, according to Posner and Raichle, when attention is redirected, neural processing of the new location is enhanced; stimulus information presented at the tobe-attended location is emphasized, and the brain circuitry underlying this operation becomes more active.

As you might expect, patients with damage to the pulvinar do not show the enhanced processing of which other people are capable when attending to a stimulus in a particular location

The idea that attention consists of several different processes that operate independently has received some support from clinical psychological studies of children and adults with ADHD

classic work suggests that ADHD clients suffer not so much from an inability to be alert or to devote mental resources to a task,as from an inability to sustain vigilance on dull, boring, repetitive tasks, such as “independent schoolwork, homework, or chore performance.

the major deficit in ADHD children is an inability to inhibit an ongoing response (for example, talking or playing a game when asked to do homework), an inability that may be a part of Posner and Raichle’s enhance operation

Posner and Raichle’s (1994) description of attentional networks postulated that distinct areas of the brain underlie distinct cognitive processes.

 Posner more recently has described three different attentional networks that recruit individual cognitive processes (such as moving or disengaging).

1.     These are the alerting network, responsible for achieving and maintaining an alert state;

2.     the orienting network, which selects information from sensory input;

3.      and the executive control network, which resolves conflicts among different response

Posner believes that the alerting network is associated with the frontal and parietal regions of the right hemisphere;

the orienting network with areas of both the parietal and frontal areas;

and the executive control network with the frontal lobes, especially the prefrontal cortex.

Event-Related Potentials and Selective Attention

Cognitive neuropsychologists have reported some fairly dramatic findings suggesting that information is processed very differently in attended versus unattended channels.

Some of this work relies on measures such as a series of electrical potential recordings (electroencephalogram, or EEG) taken from the scalp of a participant

Banich (1997) has described the methodology of a typical study.

●       Participants are asked to listen to one channel and to count long-duration tones. Shortduration tones and long-duration tones are both presented in each channel, attended and unattended.

●      Researchers keep track of the ERPs to each stimulus. Results from many studies show that ERPs differ as a function of whether a stimulus was attended to

●      Notice that the amplitude of the waveforms (that is, how much the waveform deviates from the horizontal) is usually much larger for the attended than for the unattended stimulus

●      This difference usually begins 80 milliseconds after presentation of the stimulus, which is enough time for information to travel from the sensory receptors in the ears to the cerebral hemispheres, suggesting that the effect occurs in the brain, not in the ears