Attention

Attention purpose

- Select behaviourally relevant input
- Ignore the rest

What are the two features of attention classification based on motive?

Exogenous and endogenous

What are the different types of attention based on spatial characteristics?

- Spatial
- Feature-based
- Object-based
- Focused
- Divided

What are the two types of attention based on visibility?

- Overt
- Covert

What feature of attention allows for concentration on a specific stimulus?

Selective

What feature of attention is maintained over a prolonged period?

Sustained

What are the different sensory modalities that attention can be classified into?

- Visual
- Auditory
- Tactile

What are the two categories of attention based on the source of focus?

- External
- Internal

Cocktail Party Phenomenon

- Top-down
- Bottom-up

Top-down attention

- Focussed (even in noisy room)

Bottom-up attention

- Stimuli captures attention when not selectively paying attention to it first

Top-down attention features

- Goal-directed
- Internal priorities
- Task demands

Bottom-up attention features

- Stimulus driven
- Salient / unexpected features

Everyday perception is driven by:

- Interaction of top-down and bottom-up attention

Cocktail Party Model Dichotic Listening Task *

- Headphones played 2 different stories
- Ppt asked to repeat one
- Voices were manipulated

Cocktail Party Model results *

- Ppt couldn't focus on one story if voices were the same
- More different voices = easier (gender, pitch)

Filter theory

-A selective filter interrupts the access of irrelevant input to the subsequent processes

-The selection is based on the physical characteristics of the input

-The excluded input remains briefly in the sensory register and is rejected unless attended to rapidly

-The selective filter rejects the unattended input at an early stage of processing

What was the selective filter designed to prevent?

the information processing system from becoming overloaded

Attenuation theory

The attenuator reduces, but not eliminates, unattended material.

The information is analysed if its activation exceeds a threshold, which is affected by:

• Context

• Subjective importance

• Saliency

• Priming

Late selection model

All stimuli are fully analysed for meaning & only then filtering takes place based on physical properties and meaning

Load Theory

Suggests there’s evidence supporting both early and late selection depending on the situation

Spacial attention

-Attention is directed to an area of the visual field (visual space)

-Often described as a “spotlight”

Exogenous (peripheral) cues

Appear at or near the target location in the periphery

Capture attention automatically

Effect is fast (onset ~100ms) but short-lived

Driven by bottom-up processes

Example: a sudden flash in your peripheral vision

Endogenous (central) cues

Typically appear at fixation (e.g., an arrow pointing left or

right)

Require voluntary interpretation — you must read and follow the cue

Effect is slower (onset ~300ms) but more sustained

Driven by top-down processes

Example: a sign telling you where to look

Inhibition of Return

• After attention is directed to a location, there is a cost to returning to that location shortly afterwards

-Only produced by exogenous cues

Gaze cueing

seeing another persons gaze automatically shifts your attention in the same direction

the effect is reflexive and cannot be suppressed

PET scans

• Positron emission tomography

-Participants are injected with a radioactive tracer that accumulates in active brain regions. Scanner detects signal emitted by the tracer to produce images of regional blood flow

fMRI scans

-functional Magnetic Resonance Imaging

-Measures the bold signal - a proxy for neural activity

Dorsal frontoparietal network

-Active during voluntary, goal-driven, top-down orienting

-Bilateral; involved in preparing attention toward expected locations

Feature-based attention

-When you attend to a feature, processing of that feature is enhanced across the entire visual field, not just at one location

-If you are looking for a red object, all red things get a processing boost — even ones you are not directly looking at

Feature-similarity gain model

-Neural responses are scaled according to how similar a

stimulus is to the attended feature

-The closer a stimulus matches what you are attending to, the stronger the neural response - regardless of where it appears in the visual field

Real-life relevance

-When you are looking for something specific, you tune your visual system to that feature — you are in a particular attentional set

-This makes you faster at detecting matching stimuli but less sensitive to things that don't match your current set

-Looked-but-did-not-see: Drivers with an attentional set tuned to a specific feature (colour) were more likely to miss an unexpected hazard that did not share that feature

Object-based attention

directs attention to coherent forms or objects in the visual field

Rapid Serial Visual Presentation (RSVP)

A method in which stimuli are presented one at a time at a single location in rapid succession

Attentional blink

In the RSVP task, participants see a train of letters each presented very briefly (15ms)

Two conditions:

• Control: The task was to detect the presence (or absence) of the probe (X).

• Experimental: The task was to indicate the white letter (target) AND to detect the presence of the probe (X).

results of Attentional blink

-Control: ppts detected the probe almost always

-Experimental: the probability to detect the probe depends on its position after the target.

Psychological Refractory Period

people are slow to perform a task if it occurs closely after another one

Hemispatial neglect

reduced awareness of stimuli on one side of space (affects 2/3 of right hemisphere stroke patients)

fail to acknowledge contralesional stimuli, people & their own body parts

Representational neglect

only could imagine the right side of images

info not lost from memory and instead spatially inaccessible

Simultagnosia

only one object wins the competition for attentional selection at any moment

Optic ataxia

can describe where something is but cannot reach for it accurately

Ocular apraxia

cannot voluntarily move their eyes to a target even though reflexive eye movements are preserved