PerLecture 6 - Visual Attention Lecture Notes

A comprehensive set of vocabulary flashcards covering the definitions of attention types, visual search mechanisms, orientation tasks, and clinical conditions related to visual attention.

Attention

Selectively concentrating on a discrete aspect of information while ignoring other perceivable information.

Selective Attention

Selectively concentrating on a specific aspect of a scene while ignoring other aspects.

Inattentional blindness

The failure to notice a fully visible, but unexpected, object because attention was engaged elsewhere (selective attention).

Drew et al. ($2013$) Study

Found that over $80\%$ of radiologists missed a gorilla $48x$ the size of a nodule when identifying cancerous nodules on a lung scan.

Divided Attention

Giving attention to multiple sources of information at once.

Sustained Attention

Giving attention to one object for a sustained period of time.

Spatial Attention

Attention directed to a specific location in space.

Object-based Attention

Attention directed to a specific object.

Feature-based Attention

Attention directed to a specific feature of an object.

Visual Search

The search for a particular object or feature (target) among distractors.

Covert Attention

Mentally focussing your attention without moving your eyes.

Overt Attention

Selectively attending to an item/location by looking at it.

Exogenous Orientation

Being automatically or unconsciously oriented towards an external signal or cue.

Endogenous Orientation

Intentionally orienting according to an observer's goals or desires, also known as concentration.

Fovea

Part of the eye that fixates on areas with high visual activity; it contains many cones for high visual acuity and clarity.

Fixation

Maintaining the visual gaze on a single location.

Saccade

Quick, simultaneous movement of both eyes in the same direction.

Posner’s Pre-cueing Task

An experimental protocol where individuals are presented with a fixation, a cue, and a target to measure response times.

Valid Trial

A trial in the Posner task where the cue correctly shows the direction the target will later appear in.

Invalid Trial

A trial in the Posner task where the cue shows the opposite direction of where the target appears.

Posner et al ($1978$) Finding

Discovered that cues directing attention nearer to an object can increase the perceived contrast of that object.

Psychological Misdirection

Redirection of attention to irrelevant objects driven by expectations and endogenous orientation.

Physical Misdirection

Redirection of attention to irrelevant objects typically caused automatically by exogenous orientation.

Salience

The property by which an item stands out from its surroundings.

Attentional Capture

Properties of a stimulus grabbing attention beyond the observer's will, possibly exogenously.

Saliency Maps

Computed topographical descriptions of a scene based on brightness, colour contrast, and other factors.

Change Blindness

A phenomenon where an observer does not notice a change introduced into a visual stimulus.

Pop out

When a target is found fast during visual search, and search time does not typically change with an increase of distractors.

Serial Search

A visual search where search time increases linearly as the number of distractors increase because each must be searched one by one.

Feature Search

A visual search where the target and distractor differ by a single feature; it is efficient, fast, and requires no attention.

Conjunction Search

A search where the target and distractor differ by more than one feature, requiring attention to bind features together.

Feature Integration Theory

Suggests conjunction searches require binding features processed in parallel by different specialized structures onto a single object.

Illusory Conjunctions

Incorrect combinations of features that occur when there is a lack of attention.

Liu ($2005$)

Implicated $V1-V4$ in attention, noting higher activity from endogenously allocated attention.

Datta & DaYoe ($2009$)

Implicated the brain regions $V1$ and $V2$ in covert attention.

Scolari et al. ($2015$)

Implicated $15$ separate regions in the frontal brian regions & parietal lobe regarding attention.

Spatial Neglect

Faliure to pay attention to visual input, typically due to a right parietal lobe lesion; categorized as a blindness.

Spatial Blindness

Condition where one can imagine an entire scene but cannot see part of the visual field.

Scotoma

Loss of visual acuity originating from any part of the visual system.

Hemianopsia

Occurs when primary visual pathways cut off input from the retinas to the cerebral hemispheres.

Extinction

When attention is so heavily drawn to one object in a field that an individual shows inattentional blindness to anything else.

Balint’s Syndrome

Condition caused by dorsal stream damage leading to simultanagnosia, reduced spatial localisation, and inability to reach for objects.

Simultanagnosia

The inability to see more than one object in a field at a time.

Driver & Spence Study

Demonstrated that auditory cues impact visual attention; response to a visual target was faster when audio originated from the same side.