Attention Flashcards
Visual Extinction
Damage to right parietal lobe
Can see stimulus on the left if there is no other competitoin (frog and sun example)
Ways to Bias Competition
Attentional Enhancement
Filter Out Distractors
Increase baseline activity
Stimulus characteristics
Inattentional Blindness:
• Failure to be aware of a visual stimulus because attention is directed away from it
i.e. Not noticing gorilla because you’re attending to the number of basketball passes
Change Blindness:
• Failure to notice the appearance/disappearance of objects between 2 alternating images
i.e. Appearance of an object in a scene
Convert orienting
Moving attention without moving eyes or head
Overt orienting
Moving eyes or head along with the focus of attention
Exogenous Orienting
Attention guided externally by a stimulus
i.e. see flashing light, attention directed there, RT is faster when stimulus is presented there
Inhibition of return
□ Slowing of reaction time associated with going back to a previously attended location
□ With longer delays, participants are slower at detecting a target in the same location as the cue
Attention initially shifts to cued location, but then shifts to another location (disengagement)
Endogenous Orienting
Attention is guided by the goals of the perceiver
• Participants asked to attend to either the central letter or the whole word § When attending to the central letter, participants were faster at making judgments about that letter, but not other letter in the word § When attending to the whole word, faster at making judgments about all the letters Top down influences- attention can be manipulated by the demands of the task
Visual Search:
• Task of detecting the presence of absence of a target object (i.e. “F”) in an array of other distracting objects (“E”, “T”)
Good example of both bottom up processing (perceptual identification of objects and features) and top down processing (using target to endogenously orient attention)
Saccade
Fast, ballistic movement of the eyes
Lateral Intraparietal Area (LIP):
• Region in the posterior parietal lobe that response to external sensory stimuli (i.e. vision, sound) and elicits a motor response (i.e. eye movements)
Neurons in this region increase activity to both endogenous (target enters receptive field) and exogenous (sudden changes in illumination) orienting
Multisensory part of teh brain
Dorso-dorsal Stream
§ Orienting within a salience map
§ Involves LIP and Frontal Eye Field (FEF)
□ Part of the frontal lobes responsible for voluntary movement of the eyes
§ Strong activity in LIP in response to a cue
Ventro-dorsal branch
§ Circuit breaker that interrupts ongoing cognitive activity to direct attention outside the current focus
§ Strongly right lateralized to right temporoparietal region
§ Activity found when detecting a target (but not when a spatial cue)
Activity enhanced when detecting an infrequent target in an unattended location
Non-Spatial Deficits From Parietal Lobe Lesions:
• Both hemispheres are involved in detecting salient stimuli, damaging one hemisphere depletes this resource
• Left and right parietal lobes have different roles in non-spatial attention
- Right= salient stimuli, left= suppression of non-salient stimuli
Phenomenal consciousness
Experience of perceiving something
Access consciousness
Ability to report on the content of awareness
Feature Integration Theory (FIT):
Spatial attention
Early selection
If distractors have the same features as the target, take longer to process because need to integrate features
Illusory conjunctions
§ Situation in which visual features of 2 different objects are incorrectly perceived as being associated with a single object
□ Individual features incorrectly combined
§ i.e. Participants say they saw a red “H” when they actually saw a blue “H” and a red “E” when stimuli are presented quickly (can’t perform serial search)
FIT and parietal lobe
• TMS applied over the parietal lobe slows conjunction searches, but not single-feature searches
§ Patients with parietal lesions often show a high level of conjunction errors
Suggests parietal lobe is important for FIT
Negative priming effect
§ Participants must name the red object and ignore the blue one
§ If the ignored object on one trial suddenly becomes the attended object in the second trial, participants are slower at naming it
§ Same effect is found if the critical object is from the same semantic category
□ Suggests that the ignored object was processes meaningfully rather than being excluded purely on the basis of its colour as would be expected by early section theories such as FIT
Biased Competition Theory
Attention is a broad set of mechanisms for reducing many inputs to limited outcomes
Competition occurs at multiple stages
i.e. familarity of object, top down signaling, salience of object..etc
Premotor Theory of Attention:
• Assumes that the orienting of attention is nothing more than preparation of motor actions
Theory of spatial attention
If attention drawn to one area, then have to shift it, requires more neural resources and therefore slower RT
Balint’s Syndrome:
Severe difficulty in spatial processing following bilateral lesions of the parietal lobe
Simultanagnosia
□ Inability to perceive more than one object at a time
□ i.e. See window, then window disappears, see a necklace, can’t see whose wearing it
Can see as single object at a time
Optic ataxia
Problems using vision to guide hand actions
Optic apraxia
Problems making appropriate eye movements
Egocentric Space:
• Map of space coded relative to the position of the body
• Main features of neglect tend to relate to this kind of space
Linked to damage to the right temporoparietal region
