2 Some Questions to Consider Is it possible to focus attention on just one thing, even when lots of other things are going on at the same time?Under what conditions can we pay attention to more than one thing at a time?What does attention research tell us about the effect of talking on cell phones while driving a car?Is it true that we are not paying attention to a large fraction of the things happening in our environment?
3 AttentionProcess of concentrating on specific features of the environment or on certain thoughts or activitiesSelective: excluding of other features of the environmentLimited: in capacity and timingBoth overt and covert: we can consciously attend to information but some information grabs our attention
4 Selective AttentionAbility to focus on one message and ignore all othersWe do not attend to a large fraction of the information in the environmentFiltering out some information and promoting other information for further processing
5 Research Method: Dichotic Listening One message is presented to the left ear and another to the right earParticipant “shadows” one message to ensure he is attending to that messageCan we completely filter out the message to the unattended ear and attend only to the shadowed message?
6 Caption: In the shadowing procedure, a person repeats out loud words he has just heard.
7 Results of Dichotic Listening Participants could not report the content of the message in unattended earKnew that there was a messageKnew the gender of the speakerHowever unattended ear is being processed at some levelCocktail party effectChange in gender is noticedChange to a tone is noticed
8 Models of Selective Attention Models of Selective AttentionWhere does the attention filter occur?Early in processingLater in processingEarly selection modelBroadbent’s filter modelIntermediate selection modelTresiman’s attenuation theoryLate selection modele.g. McKay (1973)
9 Broadbent’s Filter Model Early-selection modelFilters message before incoming information is analyzed for meaningCaption: Flow diagram of Broadbent’s filter model of attention.
10 Broadbent’s Filter Model Sensory memoryHolds all incoming information for a fraction of a secondTransfers all information to next stage
11 Broadbent’s Filter Model Identifies attended message based on physical characteristicsOnly attended message is passed on to the next stageDetectorProcesses all information to determine higher-level characteristics of the message
12 Broadbent’s Filter Model Short-term memoryReceives output of detectorHolds information for seconds and may transfer it to long-term memory
13 Broadbent’s Model Could Not Explain Broadbent’s Model Could Not ExplainParticipant’s name gets throughCocktail party phenomenonParticipants can shadow meaningful messages that switch from one ear to anotherDear Aunt Jane (Gray & Weddeburn, 1960)Effects of practice on detecting information in unattended earYou can be trained to detect in unattended earBased on the meaning of the message
14 Tresiman’s Attenuation Theory Intermediate-selection modelAttended message can be separated from unattended message early in the information-processing systemSelection can also occur laterCaption: Flow diagram for Treisman’s attenuation model of selective attention.
15 Treisman’s Attenuation Theory AttenuatorAnalyzes incoming message in terms of physical characteristics, language, and meaningAttended to message is let through the attenuator at full strengthUnattended message is let through at a much weaker strength
16 Treisman’s Attenuation Theory Dictionary unitContains words, each of which have thresholds for being activatedWords that are common or important have low thresholdsUncommon words have high thresholds
17 Caption: The dictionary unit of Treisman’s model contains words, each of which has a threshold for being detected. This graph shows the thresholds that might exist for three words. The person’s name has a low threshold, so it will be easily detected. The thresholds for the words rutabaga and boat are higher, because they are used less or are less important to this particular listener.
18 Late Selection ModelsSelection of stimuli for final processing does not occur until after information has been analyzed for meaning
19 Late Selection Models McKay (1973) In attending ear, participants heard ambiguous sentences“They were throwing stones at the bank.”In unattended ear, participants heard either“river”“money”
20 Late Selection Models McKay (1973) In test, participants had to choose which was closest to the meaning of attended to message:They threw stones toward the side of the river yesterdayThey threw stones at the savings and loan association yesterday
21 Late Selection Models McKay (1973) The meaning of the biasing word affected participants’ choiceParticipants were unaware of the presentation of the biasing words
22 Task Load and Selective Attention? Task load: how much of a person’s cognitive resources are used to accomplish a taskHigh-load: uses almost all; no resources for other tasksLow-load: uses few; resources for other tasks
23 Caption: Flanker-compatibility task Caption: Flanker-compatibility task. (a) Display in which the small square is the target, and the large square on the right is the distractor. This distractor is “compatible” because it is the same as the target. (b) Display in which the distractor is “incompatible” because it is different from the target. (c) Results of Green and Bevelier’s (2003) experiment, which found that the reaction time to indicate the presence of a target is longer for the incompatible distractor (bar I) than for the compatible distractor (bar C).
24 Flanker-Compatibility Task Can participants focus their attention on detecting the target so that the identity of the distractor will not affect their performance?
25 Flanker-Compatibility Task Low-load condition: one potential targetReaction time is longer for incompatible distractorsParticipant still had resources available to process additional information
26 Caption: Stimuli for the flanker-compatibility task in which the load is increased by adding additional stimuli to the display. The target is still the square, as in figure 4.10, so the distractor is compatible in (a) and incompatible in (b). The results, shown in (c), indicate that under this high-load condition, the reaction times are the same for both compatible and incompatible distractors. (From Green & Bevelier, 2003).
27 Flanker-Compatibility Task High-load condition: type of distractor does not affect reaction timeParticipants use all resourcesNo resources to process the distractor
28 Low load: experts’ performance is similar to non-experts Video-Game ExpertsLow load: experts’ performance is similar to non-expertsHigh load: experts still had enough resources left to process distractorsPerformance transferable to flanker-compatibility task
29 Effect of Load on Selective Attention High-load experiments support early selectionLow-load experiments support late selection
30 Divided AttentionPractice enables people to simultaneously do two things that were difficult at firstSpelke et al. (1976)After hours of practice, participants could read and categorize dictated words
31 Schneider and Shiffrin (1977) Divided AttentionSchneider and Shiffrin (1977)Divide attention between remembering target and monitoring rapidly presented stimuliMemory set: 1-4 target charactersTest frames: could contain random dot patterns, a target, distractors
32 Caption: Consistent mapping condition for Schneider and Shiffrin’s (1977) experiment.
33 Caption: Improvement in performance with practice in Schneider and Schiffrin’s (1977) experiment. The arrow indicates the point at which participants reported that the task had become automatic. This is the result of experiments in which there were four target stimuli in the memory set and two stimuli in each frame.
34 Divided AttentionConsistent mapping condition: target would be numbers, and distractors would be lettersOver time, participants became able to divide their attentionAutomatic processing occurs without intention and only uses some of a person’s cognitive resources
35 Divided Attention Stroop effect Name of the word interferes with the ability to name the ink colorCannot avoid paying attention to the meanings of the words
36 Caption: Varied mapping condition for Schneider and Shiffrin’s (1977) experiment. This is more difficult than the consistent mapping condition because all the characters are letters and also because a character that was a distractor on one trial (like the T) can become a target on another trial, and a character that was in the memory set on one trial (like the P) can become a distractor on another trial.
37 Schneider and Shiffrin (1977) Divided AttentionSchneider and Shiffrin (1977)Varied mapping condition: rules changed from trial to trailOver time, participants never achieved automatic processing
38 Divided AttentionControlled processing: participants paid close attention, and their search was slow and controlled
39 Caption: Comparing performance on the consistent and varied mapping tasks. Note that the horizontal axis indicates the duration of each target frame. These graphs show that frames must be presented for longer durations to achieve good performance in the varied mapping condition.
40 100-car naturalistic driving study Divided Attention100-car naturalistic driving studyVideo recorders placed in carsRisk of accident is four times higher when using a cell phone
41 Strayer and Johnston (2001) Divided AttentionStrayer and Johnston (2001)Simulated driving taskParticipants on cell phone missed twice as many red lights and took longer to apply the brakesSame result using “hands-free” cell phone
42 Attention and Visual Perception Inattentional blindness: a stimulus that is not attended is not perceived, even though a person might be looking directly at it
43 Caption: Inattentional blindness experiment Caption: Inattentional blindness experiment. (a) On each trial, participants judge whether the horizontal or vertical arm is longer. (b) After a few trials, the inattention trial occurs, in which a geometric object is flashed along with the arms. (c) In the recognition test, the participant is asked to indicate which geometric object was presented.
44 Attention and Visual Perception Change blindness: if shown two versions of a picture, differences between them are not immediately apparentTask to identify differences requires concentrated attention and search
45 Caption: Frames from the video shown in the Levin and Simons’ (1997) experiment. Note that the woman on the right is wearing a scarf around her neck in shots A, C, and D, but not in shot B. Also, the color of the plates changes from red in the first three frames to white in frame D, and the hand position of the woman on the left changes between shots C and D.
46 Eye movements, attention, and perception Overt AttentionEye movements, attention, and perceptionSaccades: rapid movements of the eyes from one place to anotherFixations: short pauses on points of interestStudied by using an eye tracker
47 Bottom-up Determinants of Eye Movement Stimulus salience: areas that stand out and capture attentionBottom-up processDepends on characteristics of the stimulusColor and motion are highly salient
48 Top-Down Determinants of Eye Movements Scene schema: knowledge about what is contained in typical scenesHelp guide fixations from one area of a scene to anotherEyes movements are determined by taskEyes movements preceded motor actions by a fraction of a second
49 Caption: Sequence of fixations of a person making a peanut butter sandwich. The first fixation is on the loaf of bread.
50 Covert Attention: Attention without Eye Movements Precueing: directing attention without moving the eyesParticipants respond faster to a light at an expected location than at an unexpected locationEven when eyes kept fixed
51 Caption: Procedure for (a) valid trials and (b) invalid trials in Posner et al.’s (1978) precueing experiment; (c) the results of the experiment. The average reaction time was 245 ms for valid trials but 305 ms for invalid trials.
52 Object-Based Visual Attention Location-based: moving attention from one place to anotherObject-based: attention being directed to one place on an object
53 Object-Based Visual Attention Egly et al. (1994)Participants saw two side-by-side rectangles, followed by a target cueReaction time fastest when target appeared where indicatedReaction time was faster when the target appeared in the same rectangle
54 Object-Based Visual Attention The enhancing effect of attention spreads throughout the objectAttention can be based on theEnvironmentstatic scenes or scenes with few objectsSpecific objectdynamic events
55 Caption: Steps in Treisman’s feature integration theory Caption: Steps in Treisman’s feature integration theory. Objects are analyzed into their features in the preattentive stage, and then the features are combined later with the aid of attention.
56 Feature Integration Theory (FIT) Preattentive stageAutomaticNo effort or attentionUnaware of processObject analyzed into features
57 Feature Integration Theory (FIT) Treisman and Schmidt (1982)Participants report combination of features from different stimuliIllusory conjunctions occur because features are “free floating”
59 Feature Integration Theory (FIT) Focused attention stageAttention plays key roleFeatures are combined
60 Feature Integration Theory (FIT) Treisman and Schmidt (1982)Ignore black numbers and focus on objectsParticipants can correctly pair shapes and colors
61 Feature Integration Theory (FIT) R.M.: Patient with Balint’s syndromeInability to focus attention on individual objectsHigh number of illusory conjunctions reported
62 Feature Integration Theory (FIT) Mostly bottom-up processingTop-down processing influences processing when participants are told what they would seeTop-down processing combines with feature analysis to help one perceive things accurately
63 Physiology of Attention Attention enhances neural respondingAttentional processing is distributed across a large number of areas in the brain
64 Physiology of Covert Attention Monkey trained to fixate eyes on a dot while a peripheral light was flashedFixation only: monkey was to release bar when the fixation light dimmedFixation and attention: monkey was to release bar when peripheral dimmed
65 Caption: Top: Stimuli for Colby et al Caption: Top: Stimuli for Colby et al.’s (1995) selective attention experiment. The monkey always looked at the fixation light. A peripheral stimulus light was flashed inside the circle on the right. Below: (a) Nerve firing when the monkey was looking at the fixation light but was not paying attention to the peripheral light; (b) firing when the monkey was looking at the fixation light and paying attention to the peripheral stimulus light.
66 Physiology of Covert Attention Single cell recordings showed monkey’s response when paying attention to the peripheral light was not caused by changes of the stimulus on the retina but by the monkey’s attention to light
67 Attention Processing Distributed Across the Cortex Using fMRI to detect cortical activity during a search taskAttention to an expected direction of motion caused brain activity to increase in a number of brain areas
68 Caption: The results of Schulman and coworkers’ (1999) experiment, showing some of the brain areas activated by viewing the moving dots. The graphs indicate the amount of brain activity when participants were cued to pay attention to a particular direction of movement (red lines) and when they were cued to just passively view the moving dots (green lines).
69 Attention in Social Situations: Autism Autism: serious developmental disorder in which one of the major symptoms is the withdrawal of contact from other people
70 Attention in Social Situations: Autism Can solve reasoning problems that involve social situationsCannot function when placed in an actual social situationThis may be due to the way those with autism observe what is happening
71 Attention in Social Situations: Autism Non-autistic observers look to eyes to assess emotional reactionAutistic observers look to the mouth or off to the side of the face to assess emotional reaction
72 Attention in Social Situations: Autism Autistic people’s attention (or lack thereof) may be one way in which they see things differently in the environment