9.1 Selective attention

Selective attention is our brain's superpower, allowing us to focus on what matters while ignoring distractions. It's how we navigate a noisy world, picking out important information from the constant stream of sensory input bombarding our senses.

This topic explores key phenomena like the cocktail party effect and inattentional blindness. We'll look at how our brains filter information, the limits of our attention, and how factors like perceptual load and individual differences shape our ability to selectively attend.

Definition of selective attention

• Selective attention involves focusing on specific stimuli while ignoring or filtering out irrelevant information
• Enables efficient processing of important sensory input in complex environments with numerous distractions
• Necessary for effectively navigating and interacting with the world by prioritizing pertinent details

Cocktail party effect

• Phenomenon where individuals can selectively attend to a particular conversation or sound source amidst competing auditory stimuli
• Demonstrates the ability to focus attention on a target stimulus while filtering out background noise
• Relies on both bottom-up (e.g., pitch, volume) and top-down (e.g., relevance, familiarity) factors to guide attentional selection

Dichotic listening tasks

• Experimental paradigm used to study selective auditory attention by presenting different stimuli simultaneously to each ear
• Participants are instructed to attend to information presented in one ear while ignoring input from the other ear

Attended vs unattended messages

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• Attended messages are processed more deeply and can be recalled more accurately than unattended messages
• Unattended messages often go unnoticed, demonstrating the selectivity of attention and the filtering of irrelevant information
• However, certain salient or personally relevant stimuli in the unattended channel may capture attention (e.g., one's name)

Early vs late selection models

• Early selection models propose that attention filters irrelevant information early in the perceptual process, based on physical features
• Late selection models suggest that all stimuli are processed semantically before attention selects relevant information for further processing
• Current theories often incorporate aspects of both models, acknowledging the flexibility of attentional selection depending on task demands and perceptual load

Visual search

• Process of locating a target stimulus among distractors in a visual scene
• Efficiency of visual search depends on the similarity between the target and distractors and the complexity of the search array

Feature integration theory

• Proposed by Anne Treisman to explain how features are combined to form object representations in visual search
• Suggests that early visual processing occurs in parallel for basic features (e.g., color, orientation), while the integration of these features into objects requires focused attention
• Explains the difference between efficient "pop-out" searches for unique features and inefficient conjunction searches for targets defined by a combination of features

Guided search model

• Developed by Jeremy Wolfe as an extension of feature integration theory
• Proposes that visual search is guided by both bottom-up (stimulus-driven) and top-down (goal-directed) factors
• Bottom-up guidance is based on the salience of stimuli, while top-down guidance is influenced by the observer's knowledge, expectations, and goals

Top-down vs bottom-up processing

• Top-down processing is driven by higher-level cognitive factors, such as goals, expectations, and prior knowledge
• Bottom-up processing is driven by the properties of the stimuli themselves, such as salience, contrast, and motion
• Both top-down and bottom-up factors interact to guide attention in visual search and other perceptual tasks

Stroop effect

• Classic demonstration of selective attention and the automatic processing of well-learned information
• Participants are asked to name the color of the ink in which a word is printed, while ignoring the word itself
• Interference occurs when the word and ink color are incongruent (e.g., the word "blue" printed in red ink), leading to slower and less accurate responses

Response competition

• Stroop effect is thought to arise from competition between the automatic reading response and the desired color-naming response
• The incongruent condition creates conflict between the two responses, leading to slower reaction times and increased errors
• Congruent conditions (e.g., the word "red" printed in red ink) may facilitate responses due to the alignment of the word meaning and ink color

Automaticity of reading

• Reading is a highly practiced and overlearned skill for most adults, making it an automatic process that is difficult to suppress
• The automaticity of reading contributes to the Stroop effect, as participants struggle to ignore the irrelevant word meaning and focus on the ink color
• The Stroop effect highlights the challenge of selective attention when faced with conflicting automatically processed and goal-relevant information

Inattentional blindness

• Phenomenon where individuals fail to notice a fully visible but unexpected stimulus when their attention is focused elsewhere
• Occurs when attentional resources are allocated to a primary task, leaving little capacity for processing unexpected stimuli
• Demonstrates the selective nature of attention and the limitations of perceptual awareness

Simons & Chabris (1999) study

• Classic study demonstrating inattentional blindness using a video of people passing a basketball
• Participants were instructed to count the number of passes made by one team, while a person in a gorilla suit walked through the scene
• Many participants failed to notice the gorilla, illustrating the effects of selective attention on conscious perception

Change blindness

• Difficulty detecting changes in a visual scene, particularly when the change occurs during a brief disruption or distraction
• Reveals limitations in the ability to form and maintain detailed representations of the environment
• Suggests that attention is necessary for change detection and that unattended changes often go unnoticed

Flicker paradigm

• Experimental method used to study change blindness by alternating between two images with a brief blank screen in between
• The two images are identical except for a single change, which can be difficult to detect due to the disruption caused by the flicker
• Demonstrates the role of attention in change detection and the difficulty of spotting changes without focused attention

Mudsplashes

• Another technique used to study change blindness, involving the brief presentation of small, high-contrast shapes (resembling mudsplashes) on an image
• The mudsplashes serve to distract attention and mask the change, making it more difficult to detect
• Highlights the role of attention in change detection and the impact of distractions on perceptual awareness

Attentional blink

• Phenomenon where the detection of a second target stimulus is impaired when it appears shortly after the first target in a rapid stream of stimuli
• Occurs when attentional resources are temporarily depleted by processing the first target, leaving little capacity for the second target
• Demonstrates the temporal limitations of attention and the need for time to reorient attention after processing a stimulus

Rapid serial visual presentation

• Experimental paradigm used to study the attentional blink, involving the rapid presentation of a series of stimuli (e.g., letters, numbers, or pictures) at a fixed location
• Participants are typically asked to identify one or two target stimuli embedded within the stream
• The attentional blink is observed when the second target appears within a critical time window (usually 200-500ms) after the first target

Perceptual load theory

• Proposed by Nilli Lavie to explain the role of perceptual demands in selective attention
• Suggests that the efficiency of selective attention depends on the perceptual load of the task
• When perceptual load is high, attentional resources are fully engaged, leaving little spare capacity for processing irrelevant distractors

High vs low perceptual load

• High perceptual load tasks involve complex stimuli or require discriminating between similar targets and distractors, consuming most of the available attentional resources
• Low perceptual load tasks are simpler and less demanding, leaving spare attentional capacity that may involuntarily spill over to process irrelevant distractors
• The level of perceptual load determines the extent to which irrelevant information is processed, with high load leading to more effective selective attention

Attentional capture

• Phenomenon where certain stimuli automatically draw attention, even when they are irrelevant to the current task or goals
• Can be driven by bottom-up factors (e.g., salience, novelty) or top-down factors (e.g., similarity to the target, relevance to current goals)
• Attentional capture can facilitate detection of important stimuli but can also lead to distraction and impaired performance

Singleton vs non-singleton distractors

• Singleton distractors are unique items that differ from other stimuli in a single feature (e.g., a red item among green items)
• Non-singleton distractors share features with other stimuli and do not stand out in the same way
• Singleton distractors are more likely to capture attention due to their salience, even when they are irrelevant to the task

Contingent capture hypothesis

• Proposed by Folk, Remington, and Johnston to explain the role of top-down factors in attentional capture
• Suggests that attentional capture is contingent upon the match between the properties of the stimulus and the observer's attentional control settings
• Stimuli that share features with the target or are relevant to the current goals are more likely to capture attention than those that do not match the attentional set

Attentional control settings

• Top-down factors that guide the allocation of attention based on current goals, expectations, and task demands
• Attentional control settings determine which stimuli are prioritized for processing and which are filtered out as irrelevant
• Can be flexibly adjusted to optimize performance in different contexts and to meet changing task requirements

Folk, Remington & Johnston (1992) study

• Seminal study demonstrating the role of attentional control settings in attentional capture
• Participants were asked to detect a target defined by a specific feature (e.g., color or onset) while ignoring irrelevant distractors
• Distractors that matched the target-defining feature captured attention, while those that did not match the attentional set were effectively ignored
• Highlights the importance of top-down factors in guiding attentional selection and the flexibility of attentional control settings

Individual differences in attention

• People vary in their attentional abilities, including the capacity to focus, sustain, and control attention
• Individual differences in attention can be influenced by factors such as age, experience, and cognitive abilities
• Understanding individual differences in attention can inform our understanding of attentional processes and their impact on daily life

Working memory capacity

• Working memory is a cognitive system responsible for temporarily holding and manipulating information
• Individual differences in working memory capacity are related to differences in attentional control and the ability to filter out irrelevant information
• Higher working memory capacity is associated with better performance on selective attention tasks and more efficient filtering of distractors

Attention deficit hyperactivity disorder (ADHD)

• Neurodevelopmental disorder characterized by persistent inattention, hyperactivity, and impulsivity
• Individuals with ADHD often struggle with selective attention, sustained attention, and attentional control
• Studies of ADHD can provide insights into the nature of attentional deficits and the role of attention in cognitive and behavioral functioning