What are the two failures of attention? What do they mean?
- Inattentional Blindness: the failure to see a prominent stimulus, even if one is staring right at it. Caused by the participants focusing their attention on some other stimulus and not expecting the target to appear
- Change Blindness: the inability to detect changes in a scene despite looking at it directly (Slow Change Blindness: when a stimulus changes slowly, changes are often not recognized by the brain).
What is Selective Attention? How do we measure selective attention?
Selective Attention: The skill through which one focuses on one input or one task while ignoring other stimuli.
Measured by Dichotic Listening Tasks (different audio inputs presented to each ear via headphones). People tend to be accurate in saying what was said on the attending channel and shadow it back but are generally clueless about semantic content of the unattended channel.
What are the exceptions of selective attention, specifically in dichotic listening tasks?
- Physical attributes (speaker gender, speech versus music)
-Personally important semantic content (The cocktail party effect - name)
*Both do not require a lot of perspective energy and therefore are easy to recognize.
What is the Early Selection Hypothesis?
Only the attended input is analyzed and perceived. Whereas, unattended information receives little or no analysis.
What is the the main support for the early selection hypothesis?
The N1(negative1) event-related potential: EEG differences occur very quickly (80ms) after the presentation of attended vs. unattended stimuli. Attended and unattended inputs were distinguishable from each other as early as 80 ms after the onset of the stimulus.
What is the late selection hypothesis?
- All inputs are analyzed
-Selection occurs AFTER analysis
-Unattended information might be perceived but is then forgotten.
What is the support for the late selection hypothesis?
- The Muller-Lyer Illusion
- The “fins” on the lines are not consciously perceived, but they influence the perception. Dots still manage to be perceived but are selected before they make it to consciousness).
-People wrongly perceive the length of lines when including fins on lines and background dots.
Explain selection via repetition priming.
- The perceiver tries to participate in the attended channel leading the perceiver to prime the detectors needed for the (now expected) input; the prime detector fires more readily.
-Requires no effort or cognitive resources (ex: hearing your name on an unattended channel).
Explain selection via expectation-driven priming.
Expectation-driven priming: detectors for inputs you think are upcoming are deliberately primed. It is effortful and not done for unexpected inputs or inputs in which you have no interest.
Biased-competition theory: attention/expectation creates a temporary bias in neuron sensitivity. Neurons are more responsive to input with desired properties and less responsive to everything else. Additionally, desired inputs receive further processing and distractor inputs do not.
What is Spatial Attention?
The ability to focus attention on a specific location in space.
What is the Posner Spatial Attention Task?
- Goal: press a button as soon as the target appears while focusing on a central fixation mark.
-Results: If the target appeared in the expected location, participants detected it a bit more quickly. If participants were misled about the target’s position, their responses were slower than when the participants had no expectations at all.
What are the cost of attention?
Expectation-based priming
- participants perform worse in trials when they are misled than when they have no expectations.
-The costs of expectations reveal the presence of a limited-capacity system (limited mental resources at a given time).
*There are NO costs to repetition priming
Brain activity: expectation-based attention and stimulus-driven attention
The brain regions are different but overlapping
-Prefrontal (more for stimulus-driven)
-Parietal cortex (more for spatial attention)
Explain Overt vs. Covert Visual Attention
Overt: where we are foveating; highest acuity with most cones (ex: moving one’s eye). This is allowed with saccades and fixations that capture details in the fovea.
Covert: attention to the periphery (ex: not moving one’s eye)
What is the evidence for covert attention?
- benefits of attention occur without or before any eye movement.
-eye movements take approximately 180 ms
-shifts in attention to primed stimuli are detected within 150 ms.
-eyes often follow the spotlight but don’t necessarily have to.
How do you shift the attentional beam/ what are the three control system for attention?
- Orienting System: Disengage attention from one target then shift attention to a new target and engage attention on the new target.
- Altering system: maintain alert state in the brain
- Executive system: control voluntary actions (chose what we want to pay attention to).
Where do we “shine the beam of attention”?
-Interest and goals
-Importance
-Visual Prominence
-Beliefs and expectations
-Culture
What is the difference between exogenous vs. endogenous control of attention?
- Exogenous control of attention: anything that “draws” us to it; requires an effortless shift of attention; bottom-up processing; ex: blinking light, loud noise, etc.
-Endogenous control of attention: what you choose to attend; internally driven
What is the binding problem? How is it solved?
The challenge of correctly associating the features of an object, such as its color and location, with that object. Example: feature search time is NOT affected by distractors but conjunction of features search time IS.
It is solved through the feature integration theory. As your spotlight narrows (focused attention stage), you can bind everything in the spotlight together.
What are the two stages of the feature integration theroy?
- Pre-attentive Stage:
- parallel processing of features in the display; focus attention broadly
-efficient and can take in many inputs at once, BUT you may not know which features belong to which object - Focused Attention Stage
- focuses attention narrowly
-slower and sequential
-allows you to detect conjunctions and sues expectation-based priming
What is Unilateral neglect syndrome?
An inability to attend to inputs coming from one side of the body. This is typically from damage to the right parietal cortex. Emphasizes contralateral neglect!
What are two tasks that confirm unilateral neglect syndrome?
- Line Cancellation Task (Cross-out each line)
- Search Pattern
What results from unilateral neglect patients result suggest that attention is both object and space-based?
- Objects: PPA is activated with objects, and FFA in activated with faces
- Space: These patients neglect half of space.
What is divided attention?
Multiple tasks or inputs occur simultaneously. Our limited cognitive capacity and mental resources restrict how well we can multitask.
-Between-task interference increases as task similarity increases
-interference is also evident even when concurrent tasks are quite different (general resources)
-Tasks will interfere with each other if their combined demand for a resource is greater than the amount of the resource that is available.
