Unilateral Neglect Syndrome:
- Results from damage to the right parietal lobe, impacts left side of space
- Ignore all inputs coming from one side of the body
- Struggle with disengaging attention fro current focus (can’t stop focusing on one field)
- i.e. Eat food from one side of plate, reach “parties” as “ties”
Dichotic Listening:
- 2 headphones, different inputs in each ear
- Participants told to pay attention to one input (attended channel) and ignore other input (unattended channel)
- Participants told to repeat/ echo message from attended channel (called shadowing)
- Shadowing performance close to perfect, but participants heard minimal from unattended channel (could hear physical attributes- gender, pitch, volume, but not content)
Detection of Unattended Inputs:
- Words with personal importance in unattended channel are perceived
- i.e. your name, a movie you saw…etc
Perceiving and the Limits on Cognitive Capacity:
- Desired information (attended channel) is filtered and is sent for further processing
- Filtering is specific and occurs on a distractor by distractor basis (can filter specific distractors, but if a new, unknown distractor appears you won’t be able to filter it out)
Inattentional Blindness:
- Not seeing something because you weren’t expecting it and wasn’t prepared for it
- Participants asked to stare at mark at center of computer screen (fixation target)
- shape shown off to one side for 200 ms followed by a pattern mask (jumble to interrupt further processing)
- Asked participants to press one button if the horizontal line on + was longer, different button if vertical line was longer
- Trial 4- fixation target disappeared and replaced by one of three shapes (triangle, rectangle, or cross), participants asked if they saw a change (89% said they didn’t)
Change Blindness:
- Observer’s inability to detect changes in scenes they’re look at directly
- Participants shown pairs of pictures separated by brief blank interval, told to find difference between images (single thing changed), participants struggled with this task
Early vs. Late Selection:
• Early selection
◦ Unattended input receives little to no analysis and is never perceived
◦ Tracking brain activity of attended/ unattended input shows a difference in brain activity for the 2 inputs
• Late selection
◦ All inputs receive complete analysis, and selection for whether you remember it occurs after analysis finishes
◦ Apparently unnoticed distractors influences interpretation of attended stimuli- perceived, but don’t make it to consciousness
Selective Priming:
- Perception is vastly facilitated by priming of relevant detectors
- Priming is sometimes stimulus driven (produced by stimuli encountered in the past)
- Priming can be expectation driven
- Participants shown a pair of letters on a computer screen and had to decide whether the letters were the same or different
- Participants given warning sign- + sign (neutral), same letter as stimuli (primed), different letter than stimuli (misled)
Selective Priming: High Validity Condition
◦ Warning sign was a good predictor of upcoming stimuli
◦ Demonstrates expectation based priming
◦ Primed condition- warning sign produce warm up effect and expectation effect lead to fastest response times
◦ Misled condition- responses were slower than in the neutral condition, priming wrong detector takes away from the other detector
Selective Priming: Low validity condition
◦ Demonstrates stimulus based priming
◦ Warning sign was a poor predictor of upcoming stimuli
◦ Primed condition- prime rarely matches stimuli, so it doesn’t lead to specific expectations of what stimuli will be presented, but it still results in faster response times than the neutral condition because when the stimuli matched the prime, the detectors have already been warmed up and therefore fire more readily
◦ Mislead warning sign had no effect (priming the wrong detector doesn’t impact the actual detector needed)
Chronometric Studies and Spatial Attention:
- Participants asked to detect letter presentations (press button as soon as letter appeared). Participants focus on center mark, letter appear on left or right side
- Neutral warning signal- participants knew trial about to start but didn’t know which side letter would appear
- Arrow warning signal- Arrow generally accurately predicted location of stimulus to come (20% of the time arrow would mislead participants)
- Group who got the arrow did better
Limited Capacity System:
- Priming one detector takes away from another detector for expectation based priming (i.e. focusing on the left means you pay less attention to the right)
- When participants were misled (20% of arrow trial), RT was 12% slower than in neutral condition
Attention as a Spotlight:
- Visual attention can be compared to a spotlight bam
- “Beam” marks region of space where you are prepared, so inputs are processed more efficiently
- Beam can move (movement of attention, not eyes)
Control Systems:
- Control of attention depends on network of brain sites in frontal and parietal cortices
- Sites send activity to other brain regions that conduct analysis of incoming info
- Expectations modulate activity in other brain areas responsible for input
- i.e. Unilateral neglect syndrome- patients neglect objects within a spatially defined region
Orienting System:
Cluster of sites in brain needed to disengage from one target, shift and engage attention on a new target
Alerting System:
Sites responsible for achieving and maintaining an alert state in the brain
Executive System:
Sites responsible for control of voluntary actions
Attending to Objects:
- Idea that you pay attention to objects rather than positions in space
- i.e. Unilateral negelct syndrome- if asked to respond to targets on a barbell shaped frame, sees one side and ignored the other, but if you spin the barbell, they will respond to the same target even though its on a different side
Feature Binding:
- When searching for an object, it is easier to focus on an individual object at a time than looking at the entire space
- i.e. looking for a red and horizontal lines in a sea of red lines and horizontal lines
Divided Attention:
- Effort to divide focus between multiple tasks or multiple inputs
- If 2 tasks combined require more cognitive resources than available, then divided attention will fail
Specificity of Resources:
- Divided attention will be easier if simultaneously tasks are very different from each other because they likely have difference resource requirements
- Participants heard list of words in one ear, told to shadow the words, also presented with second list
- 3 conditions- second list presented into the other ear (most errors), second list presented visually, or second list presented as pictures (least errors)
Generality of Resources:
- Resources serve as an energy supply used by all tasks
- Resources are “mental tools” such as a mechanism needed for selecting and initiating responses
- Reason why tasks that are very different (i.e. talking on the phone and driving) result in poorly divided attention
Response Selector:
Resource that controls which processes go forward at any moment
Executive Control:
- Resource that sets goals and priorities, chooses strategies, controls sequence of cognitive processes
- Needed if you want to avoid interference from habits from memory or habits from situated cues
- Maintains desired goal so that goal guides actions
- Ensures mental steps are organized into right sequence
- Monitors progress of mental operations
- Inhibits automatic responses
