PSYC 3334 Cog Chapter 4 Notes

Attention is not one unified phenomenon

Attention: a family of cognitive mechanisms that combine to help us select, modulate, and sustain focus on information most relevant to behavior

• It’s capacity limited - the mind’s ability to only handle limited amounts of info at a time

  • amount of info available is more than our ability to process all of it, so stimuli compete for processing resources → attention allows us to select and prioritize some info over others

EX: Art of misdirection by Apollo Robbins

• he manipulates internal and external attention in the art of steal

Attention: external vs internal

Attention can be directed outward (to the world around us) OR inward (toward our thoughts, feelings, task rules, potential responses, and memory)

• division between external and internal is not clear and rigid

  • simply a useful way to break down complicated array of attention phenomena

    • EX: overlapping when daydreaming while sitting in class → paying too much attention to own thoughts can interfere with ability to follow lecture

Eye tracking: a research tool whereby cameras track and record where participants are looking

• sometimes used to study attention

Need to move eyes in order to piece together a high-resolution understanding of what lies before us (about 150,000 to 250,000 eye movements per day!)

• Saccades (rapid eye movements) go hand in hand with visual attention

• the act of mentally programming a saccade to a particular location seems to cue attention to that location before the eyes have started to move

EX: when ppl were cued to make a saccade to a location, they were better at discriminating a stimulus at that location even before moving their eyes

• many of the neural regions associated with eye movements overlaps with those involved in shifts of attention

Study by Alfred Yarbus

• Experiment result: patterns of lines and dots correspond to where ppl looked (the dots) and the paths their eyes took (the lines) as they viewed the face.

  • eye tracking data revealed that ppl looked mostly at the eyes, mouth, and nose bc theses were often most informative features

Importance of eye tracking

• Tools like eye tracking (which measure outwardly observable indicators of attention) are said to measure overt attention (attention directed in outwardly observable way like by moving eyes to attended location)

• Children with autism tend to focus less on eyes (which gives important social cues) than children w/o autism

  • eye tracking for infants among 6 months old, can potentially predict autism by measuring attention to facial features

BUT eye tracking doesn’t always indicate where ppl are paying attention to…

• covert attention: attention directed in a manner that is not outwardly observable

  • EX: when eavesdrop on conversation, you can do so without moving your ears

People can be safer in everyday life if they understood that overt/observable indicators do not always show where, how, or to what ppl are attending

• EX: pedestrians often believe that if a driver is looking at them, they can safely assume the driver is attending to them and will see them crossing the street

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The incorrect confusing of overt measures with covert attention has affected real world polices

• EX: Australian town decided to have ads on the street, not on billboard bc the drivers are looking on the street

Multiple-object tracking (widely used technique for assessing sustained, often covert attention)

• task involve keeping track of several identical items that move among other identical items

• EX: QB keeping track of his teammates as they run down the field, parents keeping track of their children in a crowd

3 main functions of attention

• Selection (prioritizing something over others)

  • singling out certain pieces of info among many info (core function of attention)

• modulation (changing the quality of how we process info)

• vigilance (staying alert, ready, or on task)

Selection

• people are able to selectively attend on the basis of various characteristics

  • EX: focus on sound in environment and ignore light

  • EX: spatial attention based on sight and hearing, feature-based attention, temporal attention, object-based attention

Tension of voluntary and reflexive

• Voluntary attention: intentional effort to select goal-relevant information

  • EX: trying to find a particular store in NYC with many other stores

  • EX: trying to listen to a friend at a crowded party despite loud sound

• Reflexive attention: attention to a stimulus w/o actively choosing to attend to it (attending to something bc it has seized your attention, not bc you actively chose to)

  • EX: an Ad that outshines other competing stimuli ads on NYC billboards

Spatial attention: ability to attend to regions in space (selection of a stimulus on the basis of location)

• EX: Where’s Waldo? when trying to find waldo by moving attention around the page, sampling one location, then next

Does attention simply enhance info at attended location or does it suppress info that is not at that location?

• Evidence suggest both!

  • when ppl attend to a particular location, their ability to process other info very nearby is worse than their ability to process info a little farther way

    • attention can facilitate processing at attended location, it may also dampen the process of adjacent stimuli → make sense bc stimuli adjacent to target can interfere with target processing… so it’s helpful to reduce how much you process the nearby info

Spatial attention can act like a zoom lens

• it is possible to focus on a small region in high detail or zoom out to take in a wider region at lower resolution

  • evidence from fMRI supports: when ppl were instructed to pay attention to larger array of potential target locations, the spread of corresponding neural activation in the visual system was broader. BUT lvl of neural activity within that spread decreased

    • consistent with notion that attentional resolution decreases as attentional breadth increases

Measuring selection

Posner Cueing Task

• experimental task used to reveal movement of attention in space

  • participants respond to targets on a screen as quickly as they can, and attention can be directed toward or away from target location by exogenous or endogenous cues

• Ppl are faster and more accurate at responding to a target when a cue predicts its location

Endogenous cue: a cue that engages voluntary attention and symbolically directs attention to potential target location

• EX: arrow pointing to the left or word left

• cue can appear in the middle between potential target locations (called central cue)

Exogenous cue: a cue that engages reflexive attention and appear at one of multiple target locations, attracting attention to its location instead of directing attention symbolically

• EX: flash of lightning that triggers your attention to its location

• cue can appear away from where ppl are initially fixating at (called peripheral cue)

Both cues can be valid or invalid → can either correctly or incorrectly indicate the target location

• valid cues lead to faster responses, and invalid cues lead to slower responses

  • difference in speed is typically used as an index of the movement of attention in space

• evidence suggest that some types of central cues cause attention to move reflexively → suggesting there is not a perfect overlap between whether a cue is considered central and endogenous

  • EX: picture of face with eyes looking left/right can cause people to reflexively shift their attention to the direction where the face was looking

    • also could be bc of the socially relevant cues that caused attention to move more reflexively than non-socially relevant cues

Do endogenously and exogenously cued attention reflect two different attention processes OR are they aspects of a single attentional resource?

• Answer: might reflect different attentional mechanisms

  • EX: different neural regions seem to be involved in voluntary and reflexive attention

Reflexive attentional shifts tend to be transient → benefit of a reflexively cueing a location peak after about 150 millisec. After that peak, the benefit diminishes

• these brief benefits are followed by a short period when processing at this location is actually suppressed (called inhibition of return)

  • Pro for inhibition of return: this aids our ability to find things

    • EX: if trying to find a friend in a crowd, it will be faster if some mechanism helps to avoid checking the same place over and over again

Feature-based attention: turning attention to prioritize features like color, shape, or motion

• EX: if knowing Waldo always wear red and white strips, then can specifically search for patches of red and white while ignoring anything in different colors

Neuroimaging suggest that feature-based attention involves different neural mechanism than spatial attention

• often kicks in even before a target appears, increasing activity in brain regions that are sensitive to target features even when there’s no sensory input

• When attention is tuned to a feature, visual neurons responsive to it becomes more sensitive, whereas neurons that are not responsive to that feature are suppressed

  • This tuning makes the prioritized feature more likely to reach awareness

Temporal attention: ability to pay attention to points in time

• EX: given a countdown to running race

• Similar to Posner cueing task

• with spatial attention, attention can be directed to points in time either voluntarily or involuntarily

To study:

• sometimes show participants cues that signal when a target will appear

  • EX: telling participants the target will arrive after short or longer interval

• Usually causes faster responds to targets that they accurately anticipate

Neuroimaging suggests that spatial and temporal attention involve partially overlapping brain regions

• experiment: participants were cued to target’s likely location in space (left vs right), in time (short or long interval), both, or neither.

  • Results: spatial and temporal attention activated SOME of same areas, but overlapping area is not the same

    • spatial more strongly activated areas in right parietal cortex, where temporal more strongly activated areas in left parietal cortex

Object-based attention: spread of attention through an object rather than to a point in space

• evidence suggests that when we attend to one part of an object, we often attend to the whole object automatically

Experiment: participants responded to targets that could appear at one of four locations arranged at the corners of an imaginary square (location flashed before target appeared)

• key was to compare two types of the invalid cue condition (one condition was when cue and target are in the same rectangle, one condition where they were in different rectangles)

• Result: ppl responded faster when the cue and target was in same rectangles → suggest that attention spread more easily within objects than between them

More evidence from brain lesion studies

• Pt with damage to right side of brain often exhibits spatial neglect (following a brain injury, the failure to process stimuli on one side of the visual field)

  • indicate that spatial neglect can sometimes be manifested as failures to attend to the left sides of individual objects

Biased competition model of attention

• model of attention where visual stimuli falling within the same receptive field compete with each other and in which attention biases the competition in favor of one over the other

  • EX: multiple stimuli in a cluttered environment competing to drive neural responses in the visual sys

Neurons in the visual sys respond best to stimuli in a specific part of the visual world (aka neuron’s receptive field)

• when multiple stimuli fall within the same receptive field, they compete to drive neural activity

• stimuli in different parts of visual field tend to activate different neuron populations and produce little competition

  • the closer together they appear, the more they activate overlapping neuron population → increased competition

Selective attention helps resolve this competition by biasing competition in favor of one stimulus over the others, can be:

• Bottom-up selection: attentional selection drive by the salience of physical features in the external environment

  • EX: features that stand out as very different from surrounding stimuli

• Top-down selection: stimulus selection driven by relevance to a goal

• Some suggests that emotional arousal can amplify these processes (called arousal-biased competition)

Evidence from recording of neural activity

• visual cortical neurons that respond strongly to a particular stimulus show reduced responses when other competing stimuli also appear in their receptive field

  • BUT if attention is directed to one of the competing stimuli, then the neuron’s response looks similar to when the attended item appears alone

• Signals that produce these attentional biases have been found to flow from neural networks known to support attentional control, which span the frontal and parietal cortex

Ambiguity resolution theory of visual selective attention

• theory that bc activations within the visual system can support multiple perceptual interpretations, attention helps resolve such ambiguities

  • Bc each cluster of neurons can participate in the generation of several different representations, the presence of multiple stimuli can lead to ambiguity about which mental representation corresponds to what’s out there

• attention help to resolve this by enhancing the activity of neurons tuned to the attended features, and by suppressing the activity of neurons tuned to irrelevant features

• theory is supported by converging neural recordings in both monkeys and humans (similar to biased competition)

4.3 Processing before versus after selection

When does attention do its selecting has important implications:

• If attention operates late (process meaning of everything around us before we selection what will gain entry to heightened awareness - Late selection), then it suggests that we may initially process everything, even their meaning, before selecting

  • Attention acts as a “gate” at the response or conscious awareness stage, not at the input stage

• If attention operates early (we attentionally select stimuli on the basis f physical features like color, pitch, or location, and that we register their meaning only after we select them), then it suggests selection happen based on physical features before meaning is processed

Preattentive processing: processing of info before it is attentionally selected

• during preattentive stages, stimuli are analyzed via parallel processing

  • we take in multiple stimuli quickly and all at once

• As items get attentionally selected, analysis of them processed via serial processing

  • we take processing of items one at a time

Real world implication

• EX: drivers who arrive at busy intersection and need to react to other vehicles, pedestrians and colors of stoplights → more quickly that drivers can process all the info, the lower the chance of getting into accident

Capture distinction between parallel and serial processing

• Visual search task: an experimental task in which participants look for a target embedded in an array of nontargets (parallel)

• when target is characterized by a distinctive feature (ex: red target among green nontargets) → results in visual popout (quick detection of target with distinctive features that can be processed in parallel among other items)

• Feature conjunction: in attention and perception, a combination of features like colors and shale, that distinguish a target stimulus (serial)

  • EX: red circle among red squares and blue circles

• means that ppl can only find it by combing colors and shape → search time increases as search array gets larger

Probably more accurate to characterize these processes as “efficient” and “inefficient” processing

• it may be possible for parallel processing mechanism to mimic patterns of data one would expect from serial processing mechanism (and vice versa)

• Debates over whether parallel and serial processes are categorically different are motivated by a desire to understand he mental architecture that enables us to perceive and react to the world around us

Feature integration theory

• theory that focused attention is needed to bind (integrate) multiple visual features into a cohesive object

  • Bc during preattentive processing, we may look at objects as color or different shapes, focusing on attention on objects that binds these feature together creates meaningful objects

Theory addresses the question of how do we make sense of the nearly infinite number of ways that such features can be combined?

• AKA binding problem: the challenge of figuring out which visual features in the environment combine to form cohesive perceptions of objects

• According to theory, such features are correctly bound to each other only as needed, thru the allocation of attention

Evidence/support

• illusory conjunction: the incorrect combining of features that are not actually combined in the real world, which occurs when attention is diverted away

  • study: participants viewed briefly flashed displays of colored letters flanked by two black digits. Instructed to (1) report the digits or (2) report the color of letters → either choice drew attention away from the other

  • Result: even tho letters and colors were correctly identified, ppl often combined them incorrectly

    • EX: reporting a red X when the screen showed a blue X

• Participants essentially confused which feature went together, not which feature had been present, consistent with the notion that we need attention to combine features accurately

Recent model added nuance to theory

• Guided search model: a model that posits that basic visual features are combined with top-down factors like goals and experience to make search more efficient

  • EX: ppl often find conjunctions of features faster than would be expected if they had to examine each item one at a time

• According to model, basic visual features (color and shape) are combined with top-down factors like search goals, mental representations of target, prior experience, and knowledge of context in order to produce a priority map

• the priority map is then continuously updated as attention moves through a scene

Model suggest that attention isn’t limited to fully processing one item before moving to the next

• processing of new item can begin before processing of the previous one is finished → allowing for more efficient performance than original feature integration model would predict

• attention may select items in sequence, even as processing of those items overlaps, thus speeding up the overall task

Dichotic Listening: an experimental task in which participants listen to two different messages played simultaneously over headphones

• Address Q of what happened to info that was unattended?

  • to test this, researchers needed to ensure participants were truly attending to assigned message → ask participants to repeat the message out loud as played (called shadowing)

Result: ppl were barely able to report anything about the unattended message

• the ability to attend to one message while ignoring the other has been similar to the way you can talk to a friend at a loud party → cocktail party problem (ppl’s ability to attend to one channel of info while ignoring others that impinge on the senses)

• ppl can also report there was a message present in the opposite ear, but they can’t report the meaning

  • they were able to report about physical properties of the unattended message

    • EX: noticed when speaker switched gender or when pitch was higher

Broadbent’s filter model

• notion that attention acts as a filter determining which info gains entry to more complex processing and which info gets excluded (typically based on “early” stimulus features like pitch or color, prior to the processing of semantic meaning)

  • one of first models to apply info theory to mental processes, emphasizing the idea that the mind handles info across multiple stages

• Important bc it helped formalize the idea of early selection, with attention filtering info based on physical characteristics

  • laid groundwork for early vs late selection debate

Challenges to model

• Example of participant noticing words with particularly personal relevance (like own name) when they were presented to the unattended ear

• Findings like this led some theorists to argue that ppl must process the semantic meaning even of unattended input

  • Deutsch argued that attention is characterized by late selection, where all incoming info is processed for meaning, and where attentional selection occurs only as the final gateway to conscious awareness

Treisman’s Attenuator Model (evidence for both early and late selection)

• a model of attentional filtering where different types of info have different thresholds for being selected and reaching awareness

• Proposed that attentional selection begins based on early, physical properties but does not fully block unattended info

  • instead, the unattended signal is weakened, or attenuated, while the attended info is fully processed

    • accounts attempt to explain how particularly meaningful stimuli like name might still be noticed even when unattended

Different types of info have different thresholds for reaching awareness

• very meaningful or familar info has a lower threshold → even a weak signal may be enough to reach awareness

  • EX: most of what a person say across a noisy room might fail to reach threshold, but if person say your name, you’re more likely to hear it

Evidence for a flexible locus of selection

• Perceptual load theory: the instructional design theory that learning can be facilitated by understanding different types of cognitive load such as the difficulty of the material, the learner’s skill lvl and the manner in which the material is taught

Much depends on the demans of the attended tasks

• if attended task is very demanding (high perceptual load), then attentional resources will largely be occupied with few spare attentional resources for processing unattended info

  • unattended info will then be filtered out at an early stage of processing and will neither reach awareness nor interfere with the attended task

• But if attend task is easy (low perceptual load), it may occupy few attentional resources, allowing attention to be “spill over” onto other items

  • unattended info is likely to be analyzed to greater extent and will be more likely to reach awareness and interfere with task at hand

4.4 Modulation: the process by which attention affects perception of a stimulus

• the way attention can change the way we perceive a stimulus

Vigilance: related to sustained attention, a state of heightened attentional anticipation that enables people to better respond to stimuli before they appear

• a state of heightened readiness and anticipation that can enable us to better respond to stimuli when they appear

Modulation → attention can change the way things look

• Experiment: viewed two Gabor patches (stripped patterns commonly used in vision research) → had to decide which patch had higher contrast and report whether patch was tilted right or left

  • before patches appeared, a attention-grabbing cue flashed either between them or at one of patch’s location

    • purpose of cue: manipulate where ppl directed their attention

      • If cue is between 2 patches = unbiased tilt judgement (neither patch received focused attention)

      • if cue flashed on one location, participants are more likely to report the tilt of patch at flashed location → reflecting they perceived that patch as having higher contrast even when it didn’t (spatial attention altered perceived contrast

Vigilance

• lapses in vigilance or sustained attention can result in errors at work or poor grades in school

Measure with continuous performance task

• an experimental task where participants are required to stay focused for a prolonged period

  • EX: ppl viewed letters that appear one at a time and need to press a key each time the letter X follows the letter A

    • Performance can either be attentive or not (it changes)

      • Even missing out a little sleep can impair the ability to stay vigilantly on task

• fMRI can reveal when a person is attentive or when they are unfocused and distractable (results in slowing and errors)

• tasks are also sensitive to brain damage and have been widely used by neuropsychologists

Real-world importance

• EX: analyzing millions of trials of a gamified smartphone app (Airport scanner), one research group found ppl were poor at detecting targets that appeared very rarely

  • ppl’s ability to stay vigilant can be trained

• using fMRI, researchers monitored ppl’s brain activities as they tried to sustain attention on a prolong sequence of images

  • when the neural activity indicated a lapse in focus, the difficulty of the task was ramped up to motivate them to re-establish focus

• ppl who received this training subsequently showed improved ability to maintain vigilance

4.5 Link between attention and awareness

• attentional distraction can be a big reason why ppl fail to notice important details of crimes that happen right in front of them

Inattentional blindness: phenomenon where ppl fail to notice an unexpected item right in front of their eyes when their attention is preoccupied

• coined by perception researchers Mach and Rock (tried to understand whether some kind of stimuli were more likely to capture awareness than others)

• Experiment: a cross appeared for 200 milisec, followed by a patterned mask to make the cross harder to see

  • participants indicated whether the horizontal or vertical parts of cross was longest → task was designed to preoccupy attention

• on Critical trial, an additional object unexpectedly appeared

  • Result: participants experienced a high degree of inattentional blindness

    • only meaningful stimuli like an iconic smiley face were more likely to be noticed (tho they weren’t noticed ALL the time)

  • Concluded that conscious perception relies on the availability of attention → stimuli that are not attended will NOT reach awareness

EX: monkey business illusion where ppl failed to notice an unexpected gorilla

• attentional preoccupation often causes us to miss the most obvious things

• inattentional blindness is influenced by our expectations

  • if you expected a gorilla, you probably saw the gorilla, but you might still have missed the player who left the game or changing color of the curtain

• researchers using eye trackers have found that ppl who miss seeing the unexpected object look at it for about the same amount of time as those who do see it → inattentional blindness reveals that despite what the eyes register, the things that we become aware of depend on which aspect of visual info in front of our eyes we select for further processing (what we attend to)

Called selective looking in early days

• in early demonstrations, the unnoticed event was less unusual (EX: women carrying an umbrella) and they were created by superimposing videos in a way that looked transparent and unnatural → making it unclear whether the phenomenon would generalize in real life

Real-world consequences

• EX: traffic accidents bc drivers failed to notice another vehicle or pedestrian, despite looking right at them

  • called “looked-but-failed-to-see” accidents

• in study that highlights the relevance of inattentional blindness in the health system, 83% of radiologists tasked with detecting small nodules in lung scans failed to notice something as striking as a photo of gorilla placed in the scan, even tho it was 48 times as large as the nodules they searched for

Role of feature-based attention in inattentional blindness

• Experiment: participants kept track of 4 white shapes that moved around a computerized display, while ignoring 4 black shapes.

  • had to count the number of times the white shapes touched the display edges

• on Critical trail, a novel white, black, or gray shape enter and travel across the display

  • when asked, almost no one noticed the black shape, almost everyone noticed the white shape, and some ppl noticed gray shapes

    • when asked to track 4 black shapes instead, the pattern reversed

  • suggests that ppl are most likely to notice unexpected objects that contain features that they have tuned their attention for

Real world implication

• study where ppl “drove” in VR cityscape while looking for a road sign of a particular color.

  • when a motorcycle veered into path, ppl were less likely to collide with it when it matched the color of the road sign they were looking for

Change blindness: failure to notice often large changes from one view to the next

EX: ordered a meal from one waiter but then failed to notice it was a different waiter who gave you the check

• experiment: ppl saw an array of objects, which disappeared and was then replaced with a new array (some objects may or may not have been changed)

  • were asked to select items that had been in the first array and items that had been in the second array

• Result: when a change occurred, ppl were often able to recognize both the first and second critical items even when they didn’t notice that a change had occurred

  • they seen and remembered all the items, but they just didn’t compare their 2 views

Different than inattentional blindness

• change blindness can sometimes occur not bc ppl fail to notice a stimulus, but bc ppl fail to compare two views of it in memory

Real world application

• in one study, experimenter stopped a stranger on camopus and asked for directions

  • midway thru the conversation, two ppl carrying a door rudely walked between them and blocked view of each other

    • the experimenter then changed to continue the conversation

• Result: 53% of strangers failed to notice the person they were talking to changed to a different person

  • ppl who did notice the change were roughly the same age as experimenters, whereas ppl who missed were older

• when repeated with construction workers, the proportion of same-age participants who noticed a change dropped to 33%

  • suggest our likelihood of noticing when a person changes depends on what aspects of a person we attend to

    • EX: when talking to an apparent out-group member, participants may have encoded their features enough to classify them as belonging in another social group

      • but if talking to in-group member, participants may have encoded their individuating features

Attentional Blink

• the failure to see the second of two targets in a rapid succession of items when it appears soon after the first target

  • Can occur even tho ppl are otherwise able to process visual stimuli at very fast speeds

• attention appears to need a “resting period” before a second item can be brought into conscious awareness

  • meaning we are limited in how quickly we can allocate attention to 2 points in time

Use of rapid serial visual presentation task (RSVP): a task that involves searching for targets appearing within a very rapid sequence of items

• reported having trouble reporting the second target if it appeared within about a half second of the first

Factors in attentional blink

• suggests ppl have difficulty reporting the second target bc of difficulty retrieving from short-term memory

• Another suggest that all items are identified at an early stage of perceuptual processing, but the info quickly deteriorates and becomes inaccessible unless it is quickly solidified in visual short-term memory (two-stage model)

  • the experience of trying to remember what you just saw (when it hasn’t have a chance to solidify) is akin to trying to remember a dream as you wake up (it quickly fades and too easily forgetten)

• suggest that regular meditation can lead to reduce attentional blinks (maybe thru improved attentional control that enable ppl to allocate their attention more efficiently)

Not being able to report what you saw doesn’t mean you didn’t see it

• evidence suggests that stimuli are identified at an early stage of processing, even when they fail to reach awareness

  • EX: when ppl fail to see the second target word in an attentional blink task, neural signatures indicative of word processing are still observable

Attention and neural correlates of Consciousness

• attention may be necessary for awareness, but it’s not always sufficient

Demonstration from patients with blindsight (but can still respond to and localize visual stimuli despite not being able to see them)

• pt with blindsight have been observed to shift attention to cues presented to their blind fields despite having no conscious awareness of the cues, consistent with attention not always leading to awareness

One approach to understand relationship between attention and awareness

• Neural correlates of consciousness: minimum neural mechanisms that need to be active for a person to be aware of something

  • how does neural processes give rise to states of awareness?

According to global neuronal workspace theory, we become more consciously aware of something when it engages neural activity across a distributed network of brain regions that work together

• the proposal that we become conscious of info when multiple areas and networks across the brain become rhythmically synchronized

• requires both a sufficiently strong stimulus signal (sensory input) and attention

  • if sensory input is weak, it activates only early sensory areas and stay subliminal

  • if sensory input is strong but not attended, it can spread to areas like parietal lobe and enter a preconscious state → meaning it has potential to reach awareness but doesn’t quite get there (EX: inattentional blindness and attentional blink)

• in order for full awareness, stimulus must also be attended, which allows initial neural activity to synchronize with regions in the frontal cortex and deeper brain structures

Evidence suggest that temporal properties of attention play important role in shaping what we become aware of

• EX: awareness of stimuli can be modulated by whether the stimuli are presented in sync with rhythmic fluctuations of activity in the brain (aka alpha oscillations)

  • our experience of the world comes in waves rather than as one continuous flow

Finding suggest we are only able to attend to about 4 items at one time

• we arrive at a deep and perplexing question that lies a the heart of attention and perception research

  • how it is that we experience a richly detailed world?

• EX: when sitting in library, you might perceive yourself to be surrounded by bookshelves and books. Perhaps you are also aware of a view out in the window

  • how is such a rich perception possible if you can only attend to and presumably be aware of, only 4 items at a time?

Part of answer involves the complex relationship between perception and memory

• our perception of the world at any given moment is a construction of the mind, which stitches together sensory info with info from immediately preceding and anticipated views

• also appears that we are able to rapidly process the gist (overall idea of a scene) more quickly than we can process a scene’s details, and this gist helps give us the sense of a richly perceived world

4.6

Attentional capture: involuntary (reflexive) grabbing of attention by certain kinds of stimuli

• some physical stimulus properties are particularly effective, but attention can also shift reflexively as the result of experience, learning, and emotion

Saliency map: a representational layout of the visual field which locations are tagged based on their visual salience or distinctiveness. Thought to play a role in reflexive shifts of attention

• locations that differ most from their surroundings (like in color, motion) stand out as most salient and are more likely to capture attention automatically

• this idea of bottom-up salience is sightly different from the priority map in relation to guided search (which also incorporates top-down factors like goals)

Evidence of this idea comes from additional singleton task

• task: search for unique target full of distractors and report the orientation of a line embedded within the target

  • in some trails, one of nontarget distractors might stand out bc it has a unique color → ppl are slower in reporting the target, indicating that the salient feature had captured attention

    • power of such salient items to capture attention is that ppl often can’t learn to ignore them (they continue to slow target responses even after more than 2000 trials)

Like salient colors, stimuli that appear abruptly has have found to capture attention

• EX: when ppl know in advance where a target will appear, the stimuli that abruptly appear elsewhere doesn’t capture attention

  • results from other tasks (called irrelevant precue task), suggest that stimuli capture attention when they match how ppl have “tuned” their attention

• EX: when ppl know that target will appear abruptly, abruptly onsetting cues affect response time but uniquely colored one don’t

  • in contrast, when participants know the target will have a unique color, uniquely colored cues capture attention but those with sudden onset don’t

The way ppl tune their attention can shape what does or doesn’t capture it

• suggestion is that bottom-up salience triggers a powerful “attend to me” signal, but that attentional capture is not inevitable

  • in certain conditions, it can be overridden by top-down inhibition

• this view may help resolve long-standing debates over whether attentional capture is outside our control

History based guidance of attention

• EX: when you misplace your glasses, you check thru places where you have found them before

Experience can guide attention even when we’re not aware of it

• in lab-based visual search tasks, when certain locations are more likely to contain a target, ppl learn these probabilities (sometimes without realizing it) and become faster at detecting targets in those locations

Experience also shape attention thru what we’ve learned to value

• EX: ripe red strawberries = deliciousness, 100 dollars = purchasing power

• in lab, neutral stimuli (colored shape) can gain attentional priority if they’ve been paired with reward or punishment

Experiment: ppl responding to target quickly to earn money

• in each trail, uniquely colored distractor appeared and its color indicated how much money was at stake → ppl should ignore these distractors when potential reward was high

• Result: when the distractor color indicated more money, it captured attention and slowed ppl’s responses

  • showed value-modulated attentional capture: reflexive allocation of attention based on learned value

    • things we learn to associate with value capture attention reflexively to the point where it interferes with our goals

Emotion-Driven Guidance of Attention

Attentional bias: often involuntary tendency to attend to a particular type of (often-emotional) stimulus

Emotional-driven attentional bias: our tendency to direct attention to some types of stimuli over others, and when we show a preference to attend to emotional stimuli

Experiment: dot probe task

• task where participants respond quickly to a target (a dot) that could appear in one of two locations, and where an emotional or personally relevant stimulus may precede the target at the target or nontarget location

• finding: anxious participants respond more quickly when target appears at the location of the threatening stimulus → suggesting that threat drew their attention to that location

  • depression (contrast to anxiety), appears to be characterized more by a tendency to linger on negative info than to orient towards it in the first place

Attentional bias modification

• a therapeutic approach aiming to help people reduce maladaptive biases to attend to clinically relevant stimuli

  • effectiveness is mixed, with some studies reporting benefits and some showing no effect

Evidence supporting early preattentive detection of emotional stimuli

• EX: when ppl with snake phobia searched for a snake among pics of flowers, they were more quickly to find it no matter how large the search display is

  • suggesting they registered the emotional stimulus w/o having to attend serially to each display item

• led to ppl suggest that evolution has equipped us with specialized threat detection system

  • fMRI findings that amygdala exhibits heightened activity to emotional faces even when ppl’s attention is directed elsewhere

Evidence supporting not preattentively

• EX: when perceptual load is high enough, ppl don’t appear to show particular sensitively to either emotional words or self-relevant info like names

• when ppl direct attention away from faces on computer screen under conditions where task demands are high enough, fMRI results indicate no heightened amygdala activity in response to emotional faces

  • suggest that emotion-driven attention may reflect more of a difficulty in disengaging attention from emotional stimuli rather than a rapid orienting of attention to them

    • EX: gory scene may be harder to look away from, even if it didn’t initially capture attention than a nongory scene

Emotion and Temporal attention

• EX: in attentional blink. emotional stimuli that appear as firs of two target cause longer and more pronounced impairment in detecting the second target

  • when emotional items appear as second target, they appear to “break into” awareness, seemingly bypassing the processing limitations that nonemotional items are subject to

    • this pattern may involve the amygdala → among pt with amygdala damage, emotional stimuli no longer break thru into awareness

Emotional stimuli affect awareness even when ppl try to ignore them

• EX: when ppl view rapid streams of upright landscape photos and try to find the one rotated 90 degrees to left or right, they often fail to see the target when it appears within about half a sec after a task irrelevant emotional picture

  • this occurs even tho they were looking right on the target (called emotion-induced blindness)

Attention and Biological preparedness

• notions that we are biologically prepared to respond emotionally to some stimuli more than to other are consistent with evidence that some stimuli are particularly easy to associate with an emotional response (like fear)

  • EX: in one study, monkeys that had never before encountered snakes watched other monkeys exhibit fearful reaction to snakes or flowers

    • finding: more likely to exhibit similar fearful reaction to snakes than to flowers

  • suggest they didn’t learn to mimic a fearful reaction to anything → more like to do some in response to something that may have been dangerous to their evolutionary past

Emotional and attentional modulation

• EX: when an emotional face was briefly presented, ppl’s contrast sensitivity for a set of subsequently presented Gabor patches increased

• occurred even tho faces didn’t appear in the same location as Gabor patches → suggesting the effect was independent of spatial selection

Emotional state

Broaden-and-build theory: theory that positive emotions widen the range of info that ppl readily consider and attend to

• can be adaptive, helping us grow and explore new possibilities

• negative emotions can narrow focus

Experiment: watched clips designed to elicit positive, negative, or neutral emotional state

• their attentional breadth was then tested using a global-local visual processing task

  • each trial, participants saw a large “global” shape composed of smaller different “local” shapes. Asked then to choose which of two options matched the target shape (either based on global or local form)

• results: ppl who watched positive clips were more likely to match based on global form, showing a global bias consistent with broadened attention

BUT some findings refine this theory by showing not all positive emotions broadened attention equally

• positive emotions that are strongly linked to approach motivation (a desire to move closer to something) appear to actually narrow attention

  • Experiment: ppl who watched video designed to evoke approach-related positive emotion (like showing delicious dessert) were less likely to show a global bias than those who viewed video evoking positive emotion with less intense approach motivation (like funny cat videos)

Tendency to attend to emotional info may change over life span

• discovered positivity effect: tendency for older adults to dwell less on negative info and preferentially attend to positive stimuli

  • may be drive by motivational changes instead of age-related declines in cognitive capacity.

    • older adults with better cognitive function were more likely to show this effect

• one suggestion is that limited time horizon that comes with aging motivate ppl to engage in emotional maintenance that support well-being