Lecture 10 - Week 6 Tuesday - Attention (Selective)

Properties of Attention - What are the 2 properties of attention?

Attention is limited, meaning that not all sensory stimuli can be processed at the same time, and it is selective, meaning we must choose which specific stimuli to focus on.

Provisional Definition of Attention - What is the provisional definition of attention?

Attention is a cognitive process that allows for continued processing of information.

Visual Search Task - What is the visual search task and what does it tell us about attention?

This task involves searching through a stimulus array containing a target and distractors. It tells us that while some targets are identified instantly (pre-attentive), others require active attention to find, especially when distractors share features with the target.

Pop-out Phenomenon - What is the pop-out phenomenon, and when does it work and not work?

The pop-out phenomenon occurs when a target is identified incredibly easily and quickly. It works when the target differs from distractors by a single physical characteristic like color or shape, but it does not work when distractors share multiple features with the target (e.g., searching for a red circle among red squares and black circles).

Disjunctive Search - What is a disjunctive search?

A disjunctive search is a parallel search where the target differs from distractors by only one feature (like color). It is considered "pre-attentive" because reaction time remains fast regardless of the number of distractors.

Conjunctive Search - What is a conjunctive search?

A conjunctive search is a serial search where the target is defined by a combination of features (e.g., a red dot among black dots and red squares). In this search, attention is required, and reaction time increases as the number of distractors increases.

Treisman’s Cortical Maps - What is Ann Treisman’s cortical maps experiment and how does it give us a better definition for the function of attention?

Treisman proposed that the brain has individual cortical maps tuned for specific features (like color or orientation) that can monitor activity without attention. However, attention is needed to bind these separate maps together at the same spatial location, leading to a better definition of attention: the function of selection is to bind visual features into coherent objects.

Attention as a Spotlight - Is attention a spotlight?

According to Mike Posner’s Beam Metaphor, attention acts like a spotlight that moves around and enhances processing for whatever it focuses on, even if the eyes remain fixed.

Switching Attention - What are the 3 separate processes in switching attention?

The three processes are: disengage (releasing focus from the current target), move (shifting the "beam" to a new location), and engage (focusing on the new target).

Disengage Task - What part of the brain is associated with the disengage task? What does this mean for their performance?

The posterior parietal cortex is associated with disengaging. Patients with damage here perform fine on valid trials but are very slow on invalid trials because they cannot unstick their attention from the misleading cue.

Move Task - What part of the brain is associated with the move task? What does this mean for their performance?

The superior colliculus is associated with moving attention. Patients with damage here are slow to show the advantage of a cue on valid trials (needing long delays to use it) but perform normally at short delays on invalid trials because they haven't moved their attention yet.

Engage Task - What part of the brain is associated with the engaged task? What does this mean for their performance?

The thalamus is associated with engaging. Patients with damage here don't seem to use cues effectively for either valid or invalid trials; their attention "floats" and they are easily distracted by irrelevant stimuli because they cannot lock onto a target.

Posner's Architecture - How did Posner use localization and clues about architecture?

Posner used localization (identifying which brain areas handle specific tasks) as "clues about architecture" to suggest that attention is not one single thing, but a system comprised of at least three distinct sub-processes (disengage, move, engage).

Spatial Element of Attention - How are we sure that attention has a spatial element to it?

Evidence includes the fact that we point to call attention to things, the spotlight metaphor (which moves through space), and clinical cases like hemispatial neglect where patients ignore half of their visual space.

Red Ink Quiz - How does the Red ink quiz show us that attention is not a beam, and if it’s not a beam then what is it? (it switches between object and objects parts, and it’s a mix between the beam theory and the other theory)

Since subjects can focus on red words while ignoring overlapping green words, attention cannot be a simple spatial "beam" (which would process both). Instead, attention is a mix: it can select for space (beam theory) but also for objects and object parts.

Early vs. Late Filter - What is the difference between the early and late filter for attention?

The early filter suggests stimuli are filtered based on physical characteristics before semantic processing (meaning) occurs. The late filter suggests all stimuli are processed for both physical and semantic meaning before reaching the attentional filter.

Dichotic Listening & Shadowing - What is dichotic listening and what is shadowing?

Dichotic listening involves a subject listening to two different messages simultaneously (one in each ear). Shadowing is the process of repeating the message from the attended ear out loud to ensure the subject is maintaining focus.

Early Filter Support - How was the early filter of attention supported by the dichotic listening results initially, and what did it say about attention?

Early results showed subjects didn't notice semantic changes (like a different language) in the unattended ear but did notice physical changes (like a change in pitch). This suggested that unattended information is processed for physical traits but filtered out before semantic processing.

Cocktail Party Phenomenon - What is the cocktail party phenomenon, and how does it support the late filter of attention theory?

This is the ability to hear highly relevant information (like your name) from an unattended source. It supports the late filter theory because your brain must have been processing the semantics (meaning) of the background noise to recognize your name and trigger a shift in attention.

Modern View of Attention - How should we think of attention, if neither the early or late filter theories are completely correct?

Instead of a linear filter, we should think of attention as two simultaneous control processes—endogenous and exogenous—that determine how much we focus on a task versus the environment.

Attentional Control Processes - What are the two attentional control processes? Define endogenous and exogenous?

Endogenous is a top-down process under your conscious control (staying focused on a task). Exogenous is a bottom-up process driven by the environment (being pulled away by a loud noise or your name).

Feature Integration Theory - What is feature integration theory?

Developed by Anne Treisman and Garry Gelade, this is the theory that attention serves to bind together individual features (such as color and shape) into coherent objects in space. While individual features can be processed preattentively, localizing and combining them requires active attention.

Illusory Conjunctions - What are illusory conjunctions?

These are errors in which features from different objects are accidentally combined (e.g., reporting a red circle when the display actually contained a red triangle and a blue circle). According to feature integration theory, these occur when the attentional binding process is interrupted, leaving features "free floating".