Chapter 4 - Attention Flashcards
-Attention:
-the ability to focus on specific stimuli or locations in our environment
-Selective attention:
attending to one thing while ignoring others
Divided attention
paying attention to more than one thing at a time
-Selective Attention
- ability to focus on one message and ignore all others
- we do not attend to a large fraction of the information in the environment
- we filter out some information and promote other information for further processing
distraction
one stimulus interfering with the processing of another stimulus
attentional capture
rapid shifting of attention usually caused by a stimulus such as a loud noise, bright light, or sudden movement
-visual scanning
movements of the eyes from one location to another
Research Method: Dichotic Listening
- one message is presented to the left ear and another to the right ear
- participant “shadows” on message to ensure they are attending to that message
- can we completely filter out the message to the unattended ear and attend only to the shadowed message?
- Results
- participants could not report the content of the message in unattended (overshadowed) ear
- knew that there was a message
- knew the gender of the speaker
- However unattended ear being processed at some level
- cocktail party effect – filtering out other stimuli to hear what you want
- change in gender is noticed
- change to a tone is noticed
Models of Selective Attention
- where does the attention filter occur?
- early in processing
- later in processing
-Early selection model
Braodbent’s filter model
-Intermediate selection model
-Treisman’s attenuation model
-Late selection model
-McKay (1973)
Braodbent’s Filter Model
-Early Selection Model
-filters messages before incoming information are analyzed for meaning
-Sensory memory
- holds all incoming information for a fraction of a second
- transfers all information to next stage
-Filter
- identifies attended message based on physical characteristics (e.g., pitch of the speaker’s voice)
- only attended message is passed on to the next stage
-Detector
-processes all attended information to determine higher-level characteristics of the message
-Short-Term memory
- received output detector
- holds information for 10-15 seconds and may transfer it to long-term memory
-Early-selection model
-filters message before incoming information is analyzed for meaning
Broadbent’s Model Could Not Explain
- participants name gets through
- cocktail party phenomenon
- Participants can shadow meaningful messages that switch from one ear to another
- Dear Aunt Jane (Gray and Wedderburn, 1960)
- Effects of practice on detecting information in unattended ear
- you can be trained to detect unattended ear
- based on the meaning of the message
Treisman’s Attenuation Theory
-Intermediate-selection model
- attended messages can be separated from unattended messages early in the information-processing system
- selection can occur also occur later
-Attenuator
- analyzes incoming messages in terms of physical characteristics, language and meaning
- Attended to message is let through the attenuator at full strength
- Unattended message is let through at a much weaker strength
-Dictionary unit
- contains words, each of which have thresholds for being activated
- words that are common or important have low thresholds
- uncommon words have high thresholds
Late Selection Models
-selection of stimuli for final processing does not occur until after the information has been analyzed for meaning
-McKay (1973)
- in attending ear, participants heard ambiguous sentences
- “They were throwing stones at the bank”
In unattended ear, participants heard either
- “river”
- “honey”
- in test participants had to choose which was closest to the meaning of the attended message
- they threw stones toward the side of the river yesterday
- they threw stones at the savings and loan association yesterday
- the meaning of the biasing words affected the participants’ choice
- participants were unaware of the presentation of the biasing word
Load Attention Theory
- processing capacity – how much information a person can handle at any given moment
- perceptual load – the difficulty of a task
- high-load (difficult) tasks use higher amounts of processing capacity
- lower-load (easy) tasks use lower amounts of processing capacity
Flanker-Compatibility Task
-can participants focus their attention on detecting the target so that the identity of the distractor will not affect their performance?
The Stroop Test
- not only the load but also the property of the irrelevant stimulus or dimension
- The Stroop Effect
- name of the word interferes with the ability to name the ink color
- cannot avoid paying attention to the meanings of the words
Coglab: Stroop Effect
- conditions
- congruent = color and word same
- incongruent = color and word are not the same
- result
- incongruency doesn’t matter much for word reading
- incongruency hurts a lot from color naming
- Can you stop yourself from reading a word?
- if you could, then incongruent conditions wouldn’t slow you down in color naming
- automatic tasks are harder to control
- Explanation
- observers (especially college undergrads) have automatized the process of reading. Thus, the color names of the words are always processed very quicky, regardless of the color of the ink
- on the other hand, identifying colors is not a task that observers must report on very often and because it is not automatized, it is slower
- the fast and automatic processing of the color names of the word interferes with the reporting of the ink color
Divided Attention
-the Stroop Effect
- name of the words interferes with ability to name the ink color
- cannot avoid paying attention to the meanings of the word
Overt Attention
- eye movements, attention and perception
- Saccades: rapid eye movements from one place to another
- Fixations: short pauses on points of interest
- Studied by using an eye tracker
Bottom-up Determinants of Eye Movement
- stimulus salience: areas that stand out and capture attention
- bottom-up processing
- depends on characteristics of the stimulus
- color and motion are highly salient
Top-Down Determinants of Eye Movement
- scheme schema: knowledge about what is contained in typical scenes
- help guide fixations from one area of a scene to another
- Eye movements are determined by task
- eye movements precede motor actions by a fraction of a second
Covert Attention: Attention Without Eye Movements
- precueing: directing attention without moving the eyes
- participants respond faster to a light at an expected location than at an unexpected location
- even when eyes are kept fixed
-stimulus salience:
areas that stand out and capture attention
-scheme schema:
knowledge about what is contained in typical scenes
-precueing:
directing attention without moving the eyes
Coglab: Attentional Cues (Posner)
- focus visual attention to an area by using a cue
- Spotlight or zoom lens
- measure time to identify target item when:
- observer does not know where item will appear
- they know where it will appear
- cue is a briefly presented arrow which indicates where the item appears
- Results
- advance knowledge location improves performance
- amount of reduction depends on distance from cue
- attention id like a spotlight or a zoom lens
Cue Triggers “Formation of a Spotlight”
- whatever is in spotlight is attended
- more it is attended, the better it is processed
- size, shape of spotlight can be controlled
-Exogenous (outside generating) - cue
- low-level reflexes
- sudden changes (e.g., flash or movement)
- draws attention automatically
Endogenous (inside generating) - cue
- high-level control
- instruction (via some kind of visual sign or pattern)
- sends attention to requested location)
Effects of Cues
- Both types of cues control an attentional mechanism (spotlight) but reflect different strategies
- exogenous (low level control)
- bottom-up attention
- based on what is happening in the environment
- endogenous (high-level control)
- top-down control of attention
- based on what observer believes
Inhibition of Return
-(IOR) refers to the observation that the speed and accuracy with which an object is detected are first briefly enhanced (for perhaps 100-300 mS) after the object is attended, and then detection speed and accuracy are impaired (for perhaps 500-3000 mS). It has been suggested that IOR promotes exploration of new, previously unattended objects in the scene during visual search or foraging by preventing attention from returning to already-attended objects
Object-Based Visual Attention
-location based:
moving attention from one place to another
-object-based:
attention being directed to one place on an object
Egly et al. (1994)
- participants saw two side-by side rectangles, followed by a target cue
- reaction time fastest when target appeared where indicated
- reaction time was faster when the target appears in the same rectangle
- The enhancing effect of attention spreads throughout the object
-Attention can be based on the
- Environment
- static scenes or scenes with few objects
- Specific object
- dynamic events
Divided Attention
-practice enable people to simultaneously do two things that were difficult at first
-Schneider and Shiffrin (1977)
- divide attention rapidly remembering target and monitoring rapidly presented stimuli
- memory set: 1-4 target characters
- test frames: could not contain random dot patterns, a target, distractors
- automatic processing occurs without intention and only uses some of a person’s cognitive resources
-automatic processing
a type of processing that occurs with intention and at a cost of only some of a person’s cognitive resources
Divided-Attention – Distractions While Driving
- 100 car naturalistic driving study
- video recorders placed in cars
- risk of accident is 4 times higher when using a cell phone
-Strayer and Johnston (2001)
- simulated driving task
- participants on cell phone missed twice as many red lights and took longer to apply the brakes
- same result using “hands-free” cell phone
-inattentional blindness:
: a stimulus that is not attended is not perceived, even though a person might be looking directly at it
-change blindness:
if shown two versions of a picture, differences between them are not immediately apparent
- task to identify differences requires concentrated attention and search
- we are surprisingly poor at noticing certain large-scale events going on around us
- magicians have known about for ages (sleight of hand)
- measure time to detect a change in two images
- attention was drawn by flicks between images
- attention was not drawn by flicks between images
Explanation of change blindness
- attention is needed to see change
- without it, observers are “change blind”
- the impression we have of rich sensory representations is illusory
- actual sensory representations are sparse
- little is retained over time
Notes on Change Blindness
- in everyday life, we usually see change
- if something changes, creates a motion signal
- motion is an exogenous cue; draws attention
- if something interferes with drawing of attention (flicker, occlusion) then attention doesn’t go to change
- won’t see it
- attentional distraction is a major cause of traffic accidents (e.g., cell phone)
-Binding
-the process by which features such as color, form, motion, and location are combined to create our perception of a coherent object
Feature Integration Theory (FIT)
-Preattention Stage
- automatic
- no effort or attention
- Unaware of process
- object analyzed into features
-Focused attention stage
- attention plays a key role
- features are combined
-Treisman and Schmidt (1982)
-participants report combination of features from different stimuli
- illusory conjunctions occur because features are “free floating”
- ignore black numbers and focus on objects
-participants can correctly pair shapes and colors
-R.M.: Patient with Balint’s Syndrome
- inability to focus on individual objects
- high number of illusory conjunctions reported
- Mostly bottom-up processing
- top-down processing influences processing when participants are told what they would see
- top-down processing combines with a feature analysis to help one perceive things accurately
Physiology of Attention
- attention enhances neural responding
- attentional processing is distributed across many areas in the brain
Attention Processing Distributed Across the Cortex
- using fMRI to detect cortical activity during a search task
- attention to an expected direction of motion caused brain activity to increase in a number of brain areas
COGLAB: Attentional Blink
- if visual search reflexes the spatial properties of our attention, attentional blink reflexes the temporal properties of our attention
- by looking at recognition of the 2nd target as a function of separation between the two targets, we can estimate the time required to focus and break attention for stimuli
- Experiment: identify the target X and report when seen. In half the trials, there was no X
- for the control condition, subjects correctly detected the probe on 85% trials for all probe serial positions relative to the target. For the experimental condition however, the detection of the percentage correct dropped below 60% for the post-target interval from 180 to 450 mS
- the lab combines the control of experimental condition into a single RSVP stream of 19 letters each presented for 1000 mS
- two targets are presented in the RSVP stream
- the separation between the 2 targets could be 0, 2, 4, 6, and 8
- separation 0 means only one target was presented
- Results:
- identification of the 2nd target letter is very low when it quickly follows the first target letter. As temporal separation increases, identification of the 2nd letter improves
- Explanation
- when the observer sees the 1st target letter, they must attend to it to ensure that it will be remembered later. The focusing of attention to that letter apparently requires time and if the 2nd target letter appears during that time, it is not attended and not reported
Ventral attention network
which controls the attention based on salience
Dorsal attention network
which controls attention-based on top-down processes
Executive attention network
a proposed network that is extremely complex and may involve two separate networks
