Chapter 4 - External Attention

Attention

Cognitive mechanisms that combine to help us select, modulate, and sustain focus on information that might be most relevant for behavior.

External Attention

When we attend outwardly to select and modulate sensory information.

Internal Attention

When we select, modulate, and maintain internally generated information such as thoughts and memories.

Overt Attention

Looking at an object or location of interest, causing the object to fall on the fovea of the eye. It can be measured with eye-trackers.

Covert Attention

Attention is moved independently of where the eyes are pointed. Followed by Saccades (eye movements).

What is an example of using covert attention?

An example is tracking multiple objects while not directly looking at each one.

Selective Attention

The ability to focus on one source of information while ignoring other sources.

Why do we need selective attention?

We need selective attention because we have limited processing capacity and can only process so much information at once. It helps prioritize necessary information and suppress irrelevant information.

Voluntary Attention (endogenous)

Top-down Attention controlled by the individual's goals and conscious decisions.

EX: Searching for a red apple.

Reflexive attention (exogenous)?

Bottom-up attention controlled by the environment and salient information that “captures” your attention.

EX: Loud noise or bright light.

Spatial attention, according to Posner (1980)?

Attention to a spotlight that selects regions of space for special processing.

EX: Where's Waldo

Spatial cuing experiments (Posner)

Experiments that direct attention to a region of space to test if attention influences the time needed to detect a stimulus there.

What are the three types of cues in Posner’s spatial cuing experiments?

1. Valid: Cue indicates the correct location of the target.

2. Invalid: Cue indicates an incorrect location of the target.

3. Neutral: Cue provides no information about the target’s location.

Stimulus Onset Asynchrony (SOA)

The time between the onset of the cue and the onset of the target, indicating how much time you have to process the cue before the target appears.

Peripheral cues

Exogenous shifts of attention, stimulus-driven, automatic, and fast.

Symbolic cues

Endogenous shifts of attention, goal-driven, volitional, and slow.

Attentional focus in spatial attention

Processing of the selected region is enhanced, and processing at other locations is suppressed.

Feature-based attention

Directing attention to a region of space and specific features, such as color, motion, or orientation.

How does feature-based attention affect neurons?

Neurons responsive to the selected feature show an enhanced response, making the feature more noticeable. In contrast, neurons tuned to other features show a suppressed response when attention is focused on a specific feature.

Neglect Syndrome

A condition where there is damage to the parietal lobe. Individuals ignore one half of their visual field (space-based) or one half of objects (object-based).

What kind of deficits are seen in Neglect Syndrome?

The deficits are contralesional, meaning neglect occurs in the side opposite to the damaged hemisphere. Neglect Syndrome often results from damage to the right hemisphere, leading to left neglect.

What is the Ventral Attention Network responsible for?

Bottom-up attentional control, responding to salient events in the environment. Associated with exogenous attentional control.

What is the Dorsal Attention Network responsible for?

Top-down attentional control, where goals influence attention. Associated with endogenous attentional control.

Corbetta & Shulman (2002) Theory Of Neglect

Patients with neglect have damage to the to the right temporo-parietal junction affecting their stimulus-driven (exogenous) attentional system.

How does attention work in a normal individual vs Individuals with neglect when objects are competing for attention?

In normal individuals, objects compete for attention exogenously, meaning attention is drawn automatically to salient stimuli in the environment.

In neglect, objects in the neglected field can’t compete for attention exogenously. Stimuli in the neglected visual field can’t automatically draw attention to themselves.

How can attention still be allocated to the neglected visual field in neglect patients?

Through volitional shifts of attention, such as consciously directing focus.

Biased Competition Theory

Too much information at any one time leads to competition among stimuli for neural control and awareness.

How does each neuron respond to stimuli in the visual world?

Each neuron responds optimally to stimuli within a specific part of the visual world, known as the neuron’s receptive field (RF).

How does selective attention affect the competition for neural control in the visual system?

Attention can be biased bottom-up by salient stimuli or top-down based on goals.

Role of attention in awareness

Attention shapes awareness, and we are primarily aware of what we attend to.

What happens before attention is applied to a stimulus?

Basic features are processed without focused attention called preattentive processing

When does attentional selection happen during processing?

Can happen early in processing (e.g., feature detection) or later (e.g., object recognition).

Visual Search

Process of looking for a target in a display containing distractors.

EX:Finding your favorite cereal in a grocery store.

What is measured in laboratory visual search tasks?

Reaction Time (RT) to find the target is plotted as a function of set size (the number of distractors in the display). This includes both target present trials (target is there) and target absent trials (target is not there).

How does reaction time (RT) change in visual search tasks with increasing set size?

Reaction time (RT) to find the target increases as set size (number of items in the display) increases, especially for conjunction searches.

Feature search in visual search tasks?

A feature search occurs when the target is defined by a single feature (e.g., color, shape).

How does a feature search work in terms of processing?

In feature searches, the target "pops out" of the display, and it doesn’t matter how many distractors there are; reaction time remains constant regardless of set size.

Conjunction search in visual search tasks?

Occurs when the target is defined by a combination of features (e.g., a red circle among green circles and red squares). It’s done serially, meaning items are checked one at a time.

How does set size affect reaction time in a conjunction search?

Reaction time increases as the set size increases, because more items must be checked before the target is found.

Feature Integration Theory (FIT) by Treisman and Gelade (1980)

There are two distinct processing stages: Preattentive Stage and Attentive Stage.

Preattentive Stage of FIT?

Features are analyzed automatically with no effort required. This stage is parallel processing and features are registered on separate feature maps (e.g., orientation, color, size).

How are object features organized in the Preattentive Stage?

Retinotopic organization, meaning they are mapped to specific locations in the visual field based on where the features are located.

Focused Attention Stage of FIT

Features are combined to form a complete object representation. This process is known as binding and requires focused attention.

What does the Focused Attention Stage require and how does attention work?

The Focused Attention Stage requires serial attention, where attention moves from item to item, binding the features into a cohesive object representation. Prior to attention, features are free-floating.

Illusory Conjunctions

Occur when participants report a combination of features from different stimuli. This happens because features are free-floating before they are bound together through attention.

Treisman and Schmidt (1982)

Participants were asked to report two black digits (primary task) and describe the objects present (secondary task). They often reported combinations of features from different stimuli, leading to illusory conjunctions.

Dichotic Listening Task

A cognitive psychology experiment where different messages are presented to each ear, and the participant is asked to "shadow" (repeat) one message to test selective attention and the ability to filter out the unattended message.

What do participants fail to notice in the unattended ear during Dichotic Listening?

• Change in content

• Change in language

What basic features of the message in the unattended ear are processed at some level?

• Sex of the speaker (pitch of voice)

• Change in location (e.g., from left to right)

• Change from speech to another sound

What basic findings emerge from Dichotic Listening experiments?

• Participants cannot report the content of the message in the unattended ear.

• They can identify that there is a message.

• They can identify the sex of the speaker and pitch of the voice.

What are the three main models of attentional selection?

• Early selection model (Broadbent’s filter model)

• Intermediate selection model (Tresiman’s attenuation theory)

• Late selection model (McKay (1973); Deutsch & Deutsch (1963))

Broadbent's (1958) filter theory

The filter selects information before meaning is extracted, in early selection. A filter controls what inputs are further processed, selecting based on physical characteristics like location or pitch. Meaning is not extracted until after information passes through the limited capacity channel.

What is the "bottleneck" in Broadbent’s filter theory?

The bottleneck refers to the limited capacity channel, where meaning is extracted from the input after it has been filtered.

Data Broadbent’s Model Could Not Explain

Participants sometimes notice their name in the unattended channel (Moray, 1959). Participants may switch which ear they shadow if the meaningful message switches (Treisman, 1960, 1961, 1964).

Treisman’s Attenuation Theory

It suggests that incoming messages are analyzed in terms of physical characteristics, language, and meaning. The attended message passes through at full strength, and the unattended message is weakened but still processed.

Dictionary unit

Words we know, each with different activation thresholds. Common or important words have low thresholds (e.g., your name), while uncommon words have higher thresholds.

How can thresholds in Treisman’s theory be affected?

Thresholds can be lowered by context or expectations, making it easier to activate certain words.

Late Selection model (Deutsch & Deutsch, 1963)

Selection occurs after all stimuli have been processed for meaning (semantic analysis), and selection is based on meaning.

McKay’s (1973)

In a dichotic listening task, participants were unaware of biasing words (e.g., “river” or “money”) in the unattended ear, but the meaning of those words influenced their choices based on the attended message.

Example: “They were throwing stones at the bank.”

Load Theory (Lavie, 1995)

The locus of attentional selection depends on the demand of the attended task—high load tasks filter out unattended information early, while low load tasks allow unattended information to be processed later.

Perceptual Load (Lavie & Cox (1997))

Subjects performed a search task where they had to identify if an X or an N present in the center ring. They had to ignore flanking letters outside the ring which could be compatible, incompatible, or neutral. In a low load (Easy Search) task, flanker letters interfered with the task, but in a high load (Hard Search) task, flanker letters did not interfere because attentional resources were focused on the target.

What is Inattentional Blindness?

When people fail to notice an unexpected item right in front of their eyes when their attention is preoccupied demonstrating that things we become aware of require selection for further processing.

Most et al. (2001)

Detection rates higher when unexpected objects were similar in color to target objects.

What is Change Blindness?

Failure to notice large changes in a visual scene from one view to the next.

Ways to study change blindness

The Flicker technique alternates pairs of images, measuring the time taken to notice a change between frames.

Most & Astur 2007 – Inattentional Blindness & Driving

Drivers were slower to brake and more likely to hit a motorcycle when it did not match the color of the arrows they were attending to, demonstrating feature-based attention.

Temporal Attention

Temporal attention involves attending to information over time, such as when focusing on a sequence of events.

Attentional Blink

The attentional blink occurs when participants struggle to report a second target if it appears too soon after the first target, requiring a "resetting period" for attention.

How do Emotional Stimuli capture attention?

Emotional stimuli can capture attention, and this can be tested using the Dot Probe Task, where participants respond faster to targets when preceded by emotional stimuli.

What did Bradley et al. (1999) find in their Dot Probe Task with patients with Generalized Anxiety Disorder (GAD)?

Patients with GAD were faster to respond to a probe when it appeared at the location of an angry face, showing a bias toward emotionally salient stimuli.

Most et al. (2005): Attentional Rubbernecking

The tendency to focus on emotional distractors even when they are irrelevant to the task, such as in a Rapid Serial Visual Presentation (RSVP) task.

Broaden-and-Build Theory

When people are in a safe or positive mood, they have a broader attentional focus, while anxiety or negative emotions narrow attentional focus.

Fredrickson & Brannigan (2005) mood induction experiment

After a positive mood induction, participants chose more global matches in a local-global processing task, while after a negative mood induction, they chose more local matches.

You can focus more on global properties (seeing the forest) or local properties (seeing the trees).  According to the broaden and build hypothesis, if you have just watched a movie that scared you, what should happen to your focus?

You will be more locally focused

According to Treisman's attenuation model of selective attention, why are some words from the unattended channel noticed?

• The activation threshold for words change with the context you are in

• The threshold for activation is lower for important words like your name

• The threshold for activation is lower for more common words

• All of the above

• The activation threshold for words change with the context you are in

• The threshold for activation is lower for important words like your name

• The threshold for activation is lower for more common words

• All of the above

According to Corbetta and Shulman's (2002) theory of neglect, patients suffering from neglect have damage to their…?

endogenous attentional system

Which of the following would be considered an overt, endogenous shift of attention.

Moving your eyes to look at individual items in your refrigerator while looking for your yogurt

In order to find a red headed woodpecker in a forest, a birder pays attention to red, the color of the bird's head. This is an example of _______ attention.

Feature-based

According to Load Theory, in which case are people more likely to process task-irrelevant information?

Low perceptual load

According to Corbetta and Shulman (2002), what is the relationship between exogenous and endogenous attention?

The two types of attention rely on different brain networks

According to the biased competition model,…?

objects near one another in the visual scene compete with one another to be represented by neurons responding to that location

What do illusionary conjunctions demonstrate?

Binding the different features of an object together requires attention

The Most and Astur (2007) driving simulator study shows that feature-based attention can

lead to inattentional blindness for objects not possessing that feature.