PSYC 213 Lecture Notes - Lecture 8: Dorsolateral Prefrontal Cortex, Hemispatial Neglect, Reticular Formation
16 May 2018
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Lecture 008 - 02/01/2018
• 50 multiple choice questions
• What is attention?
• William James: “everyone knows what attention is” VS now: “No one knows what
attention is” (Paschler)
o Attention is actively monitoring and selecting information
• Selective attention: attention to relevant info and ignoring irrelevant info,
sometimes we fail to notice info that we haven’t for our attention (change
blindness)
o Inability to detect a change in something you are perceiving = change
blindness
• Early selection models: information is selected for attention on the basis of the
physical features of stimuli
o Shadowing tasks/ dichotic listening: people do not process the meaning of
info that is presented to an unattended ear
• Late selection models: info is selected for attention at the level of meaning
o Stroop tasks: people are slower to name the color of ink when printed in
an incongruent color name than when in congruent color name
o Variations: emotional stroop task - people take longer to name ink colors
of emotion words than neutral words (evidence that emotional content is
automatically processed even if unattended)
• The load theory: demanding tasks (high perceptual load) attention acts as
predicted by early filter moldes vs non demanding tasks attention acts like late
filter
• Attentional blink: rapid serial visual presentation of input, P have to identify
targets among distractors, if 2 targets are presented w/i 500 ms the second one
won;t be identified so attention takes time (aka resources)
• Attention disorder: hemispatial/ unilateral neglect: caused by damage to the
parietal lobes → this is a region of the brain important in top down processing
and it integrates sensory info with visuospatial info
• Unilateral neglect:
o One side of star is missing: eyesight is fine but half of her visual world
does not matter (stroke in parietal lobe so cannot create a 3D
representation of world)
o Neglects stuff in world and in her memories
• For these people, the left side of the world does not exist (or right): read only part
of a word that is on the right side, eat from one side of the plate and will
remember/ imagine half of the world
o Not about processing but about paying attention to it (because it can
affect them at the implicit level, w/o consciousness)
o Usually From right parietal lobe damage
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• Test of unilateral neglect: ask people to copy an object drawing and they will only
draw half part OR do cancellation tasl: ask them to cancel out lines (they will only
mark out half the line on the page)
• Multiple brain mechanism of attention: alerting network
• Reticular activating system: involved in basic attention or arousal (important for
wakefulness), if damaged can lead to coma
• Domain general attentional process
o Frontal lobe = general attention control
• Dorsolateral prefrontal cortex: important for selecting information relevant to a
task
• Attention cingulate cortex” important for focusing attention & mediating response
selection
o In ADHD: ACG is often not as active
• Inattentional blindness: a consequence of selective attention: failure to attend
to new events in our environment that we should see (looking w/o seeing)
• Similar but not exactly change blindness = change in a stimulus that was there
before (change blindness) versus missing a new stimuli (inattentional blindness)
• 4 characteristics for IB:
o People fail to notice event/ object
o The object/ event is fully visible (it can be seen)
o The inability to nocie object is because of attention and not visual feature
of object
o The object/ event is unexpected (effect is not due to being distracted or
not engaging attention)
• IB task: 2 main features of this task
o P aren’t expecting the target but are looking in the general area
o P are using attention resources for some other task
• Cross and a screen (mask): asked which arms are longer (vertical or horizontal)
then after a couple of trials they will put a black square in a quadrant and people
are tested for their awareness of the black square
o People don’t notice the blind square because they don’t expect it
• Can use this design to show if this can influence some people: can present
words in quadrants → participants are more likely to complete a word stem with
the word presented during a period of “inattentional blindness”
o So even though people are not attending to the stimuli, it can influence
them
• Deja vu: the impression of having experience a situation but the situation is new
→ 2 out of 3 people have reported deja vu
o More common in people w/ age (over 8) and people who are more
travelled (because they are in newer places more), can be associated w/
brain disorders (like epilepsy)
• The result of implicit priming + inattentional blindness: a new location is
perceived under distraction (inattentional blindness): below the threshold of
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