Early or Late Selective Attention, Attentional Capacity and Spatial Attention Psychology 355: Cognitive Psychology Instructor: John Miyamoto 04/10/2018:

Early or Late Selective Attention, Attentional Capacity and Spatial Attention
Psychology 355: Cognitive Psychology Instructor: John Miyamoto 04/10/2018: Lecture 03-2 Note: This Powerpoint presentation may contain macros that I wrote to help me create the slides. The macros aren’t needed to view the slides. You can disable or delete the macros without any change to the presentation.

Lecture probably ends here
Outline Where does selective attention occur in the information flow? Broadbent's early selection model of attention Treisman's attenuation model Mackay's late selection model Attention as a divisible capacity Whether selective attention occurs early or late depends on whether the task is easy or hard (demanding only part of attentional capacity or nearly all of it). Physiological evidence for visual spatial attention. Unilateral neglect, a.k.a., hemispatial neglect. Lecture probably ends here Example 1: Capacity Limitation in Spatial Attention Psych 355, Miyamoto, Spr '18

Attentional Filter Filter Inputs
Filter Hypothesis: There is a cognitive mechanism called a "filter" that allows some sensory inputs to pass to deeper levels of processing, and blocks other inputs from continued processing. Where is the attentional filter in the cognitive process? Early selection model: Broadbent’s filter model Intermediate selection model: Treisman’s attenuation theory Late selection model: McKay (1973) Filter Inputs Early filter models assume that attentional selection precedes the extraction of meaning. So early selection models must distinguish between inputs based on physical features like which ear has the sound, or color. Broadbent's Split Scan Experiment - Reminder Psych 355, Miyamoto, Spr '18

Broadbent's (1958) Split-Scan Experiment
Trials 1, 2 & 3 occur in rapid succession. Cond 1: Report letters in any order. Typical Result: Subjects says: "M, R, W", then "H, S, P". 65% correct Cond 2: Report letter pairs for each trial (pair 1, then pair 2, then pair 3) TypicalResult: Subjects says: "M, H", "R, S", "W, P". 20% correct. Subjects say Cond 2 is more difficult than Cond 1. 1. M H 2. S R 3. P W Psych 355, Miyamoto, Spr '18 How does Broadbent's filter model explain this pattern of results?

How does Broadbent's (1958) filter model explain this pattern of results?
Switching attention requires a change (retuning) of the filter. This takes time and cognitive effort. Cond 1 requires 1 switch of attention; Cond 2 requires 5 switches of attention. Therefore Cond 2 is harder (more errors; feels more difficult). NOTE: Later research has shown that the cognitive process is more complex. This example only illustrates how a Broadbent’s Filter Model explains the findings of the split scan experiment. P W S R H M Psych 355, Miyamoto, Spr '18 Problems with Broadbent's Filter Model

Problems with Broadbent's Filter Model
Problems with Broadbent’s filter model are due to the assumption of early selection (selection precedes the extraction of meaning). Cocktail Party Phenomenon: People remember hearing their own name even if it is presented in the unattended ear. Broadbent's filter model says that unattended messages are completely blocked. Cocktail Party Phenomenon should not occur. Gray & Wedderburn's (1960): "Dear Aunt Jane" experiment Psych 355, Miyamoto, Spr '18 Grey & Wedderburn – Dear Aunt Jane Experiment

Gray & Wedderburn's (1960) "Dear Aunt Jane" Experiment
Subject is told to report what you hear in your left ear. Correct response: "Dear, 7, Jane" Typical response: "Dear Aunt Jane" If Broadbent's filter is all-or-none, then subjects should give correct response. Conclusion: Subjects extract some meaning from the message in the unattended ear. Broadbent's filter leaks! Dear 9 7 Aunt Jane 6 Psych 355, Miyamoto, Spr '18 Return to Problems with Broadbent's Filter Model

Problems with Broadbent's Filter Model
Cocktail Party Phenomenon: People remember hearing their own name even if it is presented in the unattended ear. Broadbent's filter model says that unattended messages are completely blocked. Cocktail Party Phenomenon should not occur. Participants track meaningful messages that switch from one ear to another even when they are not supposed to do this. Gray & Wedderburn's (1960): "Dear Aunt Jane" experiment Effects of practice on detecting information in unattended ear You can be trained to detect information in the unattended ear (based on the meaning of the message) Psych 355, Miyamoto, Spr '18 Treisman's Attenuation Model

Treisman's Attenuation Model
The attenuator intensifies the attended message, and weakens (attenuates) the unattended message. The attenuator analyzes information in terms of (a) physical characteristics and (b) linguistic form, e.g., sentence structure. Dictionary Unit detects words according to importance, Words in the attended channel automatically get a boost in importance. Word in unattended channels can still get through if words in these channels have sufficient importance. Explain how attenuation model explains Cocktail Party Phenomenon. Explain how attenuation model explains "Dear Aunt Jane" experiment. Psych 355, Miyamoto, Spr '18 MacKay's Late Selection Model

Evidence for Late Selection (MacKay, 1973)
Subjects told to attend to the left ear. All sentences in left ear were ambiguous. Word in right ear suggests one of two interpretations for ambiguous sentence. They threw stones at the bank Money They threw stones at the bank River Psych 355, Miyamoto, Spr '18 Example of a Question Asked to the Subjects

Evidence for Late Selection (MacKay, 1973)
Later, subjects were asked: Which sentence is closer to the meaning of a sentence that you heard? They threw stones at the savings and loan association. They threw stones towards the side of the river. Finding: Word in right ear biases interpretation of sentence in left ear. They threw stones at the bank Money Result is hard to explain if selection preceeds extraction of meaning from input. They threw stones at the bank River Psych 355, Miyamoto, Spr '18 Diagram of Early vs Late Selection Models & Attenuator Model

Before Extraction of Meaning After Extraction of Meaning
Contrast Between Early Selection, Attenuator, and Late Selection Models Before Extraction of Meaning Extraction of Meaning After Extraction of Meaning Early Selection Attenuator Late Selection Psych 355, Miyamoto, Spr '18 Text Version that Contrasts Early, Intermediate & Late Selection Models

Contrast Between Early, Intermediate, and Late Selection Models
This slide is pretty much the same as the preceding slide, except that the information is stated verbally. Early selection models: Attentional selection is based exclusively on physical characteristics of the signal. Attentional selection cannot be based on meaning of signal Unattended signals (messages) are completely blocked Intermediate selection model (attenuator model) Unattended signals (messages) are weakened (attenuated), not blocked Late selection models Attentional selection can be based on meaning as well as on physical characteristics of the signal Unattended signals are only partially blocked Psych 355, Miyamoto, Spr '18 Which Is Correct? Early or Late Selection?

Which is Correct, Early Selection or Late Selection?
Evidence shows that the correct model depends on the nature of the task. Some tasks force the human to filter information at an early stage of information processing. Other tasks allow the human to filter information at later stages of information processing. Next slide clarifies the issues between early, intermediate and late selection models. Psych 355, Miyamoto, Spr '18 Is Attention a Divisible Cognitive Resource?

Is Attention a Divisible Cognitive Resource?
Hypothesis: Attention is like a finite cognitive resource. We can use up some of it, or all of it, on any given task. Figure 4.8 Left (low cognitive load): Low demand task leaves excess attention to wander to irrelevant stimuli. Figure 4.8 Right (high cognitive load): High demand task requires 100% of attention. Irrelevant stimuli are ignored. Goldstein’s Figure 4.8. Attention as a Finite Cognitive Resource Resources used by low-load primary task Remaining cognitive resources No cognitive resources remain Resources used by high-load primary task Psych 355, Miyamoto, Spr '18 Expanded Discussion of Figure 4.8: Contrast Low vs High Load Task

Influence of Cognitive Load on Early versus Late Selection
Figure 4.8 Left: Low demand task leaves excess attention to process meaning of irrelevant stimuli. When subjects are affected by meaning of irrelevant stimuli, results support late selection models. Therefore low demand task should produce results that support late selection. Goldstein's Figure 4.8. Attention as a Finite Cognitive Resource Remaining cognitive resources No cognitive resources remain Resources used by low-load primary task Resources used by high-load primary task Psych 355, Miyamoto, Spr '18 Same Slide with Discussion of Figure 4.8 Right

Influence of Cognitive Load on Early versus Late Selection
Figure 4.8 Left: Low demand task leaves excess attention to process meaning of irrelevant stimuli. When subjects are affected by meaning of irrelevant stimuli, results support late selection models. Therefore low demand task should produce results that support late selection. Figure 4.8 Right: High demand task requires 100% of attention. There is no excess attention to process meaning of irrelevant stimuli. Therefore high demand task should produce results that support early selection. Goldstein's Figure 4.8. Attention as a Finite Cognitive Resource Remaining cognitive resources No cognitive resources remain Resources used by low-load primary task Resources used by high-load primary task Table Showing Experimental Design for Testing This Hypothesis Psych 355, Miyamoto, Spr '18

Fig. 4.7: [Easy or Hard] x [Distractor Present or Absent]
Goldstein Figure Detection task was EASY or HARD. Distractor (dog face) was ABSENT (Panel a) or PRESENT (Panel b) TASK: Say "N" if "N" is present. Say "Z" if "Z" is present. EASY HARD Irrelevant ABSENT Irrelevant PRESENT EASY Condition: Non-target stimuli are "o". HARD Condition: Non-target stimuli are similar to "N" and "Z". Irrelevant stimulus ABSENT (a): No dog face in the display Irrelevant stimulus PRESENT (b): Irrelevant dog face in the display Psych 355, Miyamoto, Spr '18

Fig. 4.7: [Easy or Hard] x [Distractor Present or Absent]
Panel (b) on right: Grey tops to bars show how much the irrelevant stimulus (dog face) slowed down the RT. Irrelevant stimulus had greater influence in EASY condition. Goldstein Figure Detection task was EASY or HARD. Distractor (dog face) was ABSENT (Panel a) or PRESENT (Panel b) Interpretation: Subjects had more excess attention to divert to distractor when the task was EASY. Results Support Hypothesis: Attention is Divisible Resource Psych 355, Miyamoto, Spr '18

Results Support Hypothesis: Attention a Divisible Cognitive Resource
Hypothesis: Attention is like a finite cognitive resource. We can use up some of it, or all of it, on any given task. Figure 4.7 Left (low cognitive load): Low demand task leaves excess attention to wander to irrelevant stimuli. Figure 4.7 Right (high cognitive load): High demand task requires 100% of attention. Irrelevant stimuli are ignored. Goldstein’s Figure 4.8. Attention as a Finite Cognitive Resource Remaining cognitive resources No cognitive resources remain Resources used by low-load primary task Resources used by high-load primary task Video Game Study Psych 355, Miyamoto, Spr '18

Study of Novice & Expert Video Game Players
Low Load (easy game): Both novices and experts are affected by irrelevant stimuli. High Load (difficult game): Experts are affected by irrelevant stimuli; novices are not affected. Cognitive load has to be defined in terms of the difficulty of the task for a particular individual (it can vary from one person to the next). Conjecture (Invisible Gorilla Experiment): If subjects were trained to count passes and bounces (subjects become "experts"), then they would notice the gorilla. Psych 355, Miyamoto, Spr '18 Conclusions: Early vs Late Selection Depends on Available Excess Attention

Conclusions: Early versus Late Selection Models
Main Question: Where in the cognitive process does attentional selection occur? Early? Late? In between? Some kinds of tasks provide evidence for early selection. Other tasks provide evidence for late selection. There is evidence that early selection occurs with hard tasks; Late selection occurs with easy tasks. (Remember the issue in early versus late selection is the question whether attentional selection occurs before or after the assignment of meanings to stimuli.) Attention is like a divisible cognitive resource. Psych 355, Miyamoto, Spr '18 Define Spatial Attention. Physiological Evidence for Spatial Attention.

Spatial Attention – What Is It?
█ ▲ Fixation Point It is possible to attend to either the red rectangle or the blue triangle while maintaining eye fixation at the +. Spatial attention is attention to different locations in visual space. Spatial attention is not exactly the same as the direction that one is looking. Psych 355, Miyamoto, Spr '18 Monkey Experiment - Neuropsych Evidence for Spatial Attention

Monkey Attention Experiment (Colby, Duhamel, Goldberg, 1995)
Fixation Point Peripheral Stimulus BOTH CONDITIONS: Monkey holds down a bar while fixating the fixation point. Monkey is rewarded if he releases the bar at the “right” moment. FIXATION ONLY CONDITION: When the fixation point dims, the monkey must release the bar. FIXATION & ATTENTION CONDITION: When the peripheral stimulus dims, the monkey must release the bar. Psych 355, Miyamoto, Spr '18 Single-Cell Recording in Monkey Parietal Cortex

Single-Cell Recording in Monkey Parietal Cortex
FIXATION ONLY FIXATION & ATTENTION Firing Rate Firing Rate Also there is human fMRI evidence for spatial attention. Activity is found especially in parietal cortex, but also temporal cortex and frontal cortex. See Goldstein textbook, Fig. 4.38, p. 108. Recording is made during the period while monkey is waiting for the signal to respond. The stimulus is the same for the left & right graph, but the monkey is attending to the peripheral location on the right. Results constitute neuropsychological evidence for spatial attention (attention to the location of the peripheral stimulus). Psych 355, Miyamoto, Spr '18 Unilateral Neglect & Spatial Attention

Unilateral Neglect – A Pathology of Attention
Unilateral Neglect: A deficit of attention in which one entire half of a visual scene is simply ignored. (Discussed in Goldstein Chapter 10) The cause of unilateral neglect is often a stroke that has interrupted the flow of blood to the right parietal lobe. Figure to the right: Patient’s copy of an image (model) shows systematic deficits. This slide is based on instructional material that was downloaded from the Pearson Publishers website ( for Smith & Kosslyn (2006; ISBN ). The patient’s copy in the right column neglects the left side of the visual field (opposite to the side of brain damage). Psych 355, Miyamoto, Spr '18 Brain Diagram - Locate Parietal Lobe

Tuesday, 10 April, 2018: The Lecture Ended Here
Psych 355,, Miyamoto, Spr '18

Left Hemisphere: Note Location of Parietal Cortex
Head is facing LEFT Unilateral neglect is associated with injury to the left or right parietal cortex. Psych 355, Miyamoto, Spr '18 More Examples of Unilateral Neglect

Early or Late Selective Attention, Attentional Capacity and Spatial Attention Psychology 355: Cognitive Psychology Instructor: John Miyamoto 04/10/2018:

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Early or Late Selective Attention, Attentional Capacity and Spatial Attention Psychology 355: Cognitive Psychology Instructor: John Miyamoto 04/10/2018:

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