Next Tuesday
• Read article by Anne Treisman
Moving from Perception to Cognition
• You will now find chapters in the Cognition textbook
on reserve to be helpful
Attention
What is “attention”
• attention is poorly defined - different people mean
different things by “attention”
What is “attention”
• attention is poorly defined - different people mean
different things by “attention”
– An aroused state: a state conducive to rapid perception and
cognition. As in “pay attention!”
What is “attention”
• attention is poorly defined - different people mean
different things by “attention”
– An aroused state: a state conducive to rapid perception and
cognition. As in “pay attention!”
– Vigilance: maintaining a state of engagement - “paying
attention in class”
What is “attention”
• attention is poorly defined - different people mean
different things by “attention”
– An aroused state: a state conducive to rapid perception and
cognition. As in “pay attention!”
– Vigilance: maintaining a state of engagement - “paying
attention in class”
– Selective Attention: focusing on one object or location to
optimally deal with the sensory information coming from it
What is “attention”
• “Everyone knows what attention is. It is the
taking possession by the mind in clear and
vivid form, of one out of what seem several
simultaneously possible objects or trains of
thought...It implies withdrawal from some
things in order to deal effectively with
others…”
- William James
What is “attention”
• James’ definition emphasizes two important aspects
of attention:
What is “attention”
• James’ definition emphasizes two important aspects
of attention:
1. That attention implies a suppression of
information at unattended locations
What is “attention”
• James’ definition emphasizes two important aspects
of attention:
1. That attention implies a suppression of
information at unattended locations
2. That attention is a selection of some
information for enhanced perception or
mental operations
What is “attention”
• Enhanced Perception or mental operations?
– Further identification
– Planning appropriate response
– Encoding (storing) into memory
– Entry into awareness
Learning About Attention by Pushing
the Limits
•
Ulrich Neisser
–
Tracking one moving object out of many
Learning About Attention by Pushing
the Limits
•
Ulrich Neisser
–
Tracking one moving object out of many
–
About 50% miss the gorilla
Learning About Attention by Pushing
the Limits
•
Ulrich Neisser
–
Tracking one moving object out of many
–
About 50% miss the gorilla
–
Demonstration that unattended information is dramatically
absent from consciousness/memory
Selective Attention
A tale of bottlenecks and basketballs
Two Distinct Processes
• There are two processes that get bundled into our
idea of attention:
– orienting - shifting attention (usually in space, but also to
non-spatial features such as pitch)
– selection - what attention does to perception
• These are often confused and used interchangeably
• We’ll switch back and forth between the two, but we’ll
try to keep them separate
• First: the consequences of selection
Information Theory:
• ~1950’s: Psychologists began to think of the human
perceptual mechanisms as “information processors”
Information Theory:
• ~1950’s: Psychologists began to think of the human
perceptual mechanisms as “information processors”
• Began asking questions such as “how much
information can the human mind handle at once?”
Information Theory
• Donald Broadbent - earliest systematic investigations
of selective attention
Information Theory
• Donald Broadbent - earliest systematic investigations
of selective attention
x x x
o o o
x o o
Information Theory
• Donald Broadbent - earliest systematic investigations
of selective attention
Information Theory
• Donald Broadbent - earliest systematic investigations
of selective attention
– when simultaneous questions were asked, subject
performed poorly on all questions
Information Theory
• Donald Broadbent - earliest systematic investigations
of selective attention
•First principle of human
information processing:
capacity is limited
Information Theory
• Donald Broadbent - earliest systematic investigations
of selective attention
Information Theory
• Donald Broadbent - earliest systematic investigations
of selective attention
– when simultaneous questions were asked from physically
separate speakers, and subject instructed in advance which
question to answer, performance was nearly perfect
Information Theory
• Donald Broadbent - earliest systematic investigations
of selective attention
Second principle of human
information processing:
information sources can be
selected
Stages of Selection
• Broadbent: Early Selection - a bottleneck
exists early in the course of sensory
processing that filters out all but the attended
channel
• Alternative theory: Late Selection - the
bottleneck exists not at the lowest stages, but
at the highest - such as response planning,
memory and consciousness
Stages of Selection
Stages of Selection
• Testing Early Selection Theory - what prediction can
be made?
Stages of Selection
• Testing Early Selection Theory - what prediction can
be made?
• Information (such as meaning of words) in
unattended channel shouldn’t be processed for
meaning
Stages of Selection
• Shadowing Task: ignore one
input, repeat back the other
• Subjects are largely unaware
of unshadowed message
but…
• Certain words such as their
name distract them!?
• Why is this puzzling?
Stages of Selection
• Testing Early Selection Theory - what is another
prediction that can be made?
• Should be able to find differences in brain activity in
primary sensory areas (A1, V1)
Stages of Selection
• Electrical activity recorded at scalp (EEG) shows
differences between attended and unattended stimuli
in A1 within 90 ms
Hansen & Hillyard (1980)
Stages of Selection
• Evidence exists for both early and late selection
mechanisms
– One interpretation: early reduction in “sensory gain”
followed by late suppression of unselected information
Orienting Attention
Control of Attention
• Major Distinctions:
Voluntary
Reflexive
Control of Attention
• Major Distinctions:
Voluntary
Reflexive
Overt
Covert
Voluntary Orienting
• Attention can be oriented covertly
– a commonly used metaphor is “the spotlight of attention”
Orienting Attention
• Posner Cue - Target Paradigm:
Subject presses a button as soon as x appears
Orienting Attention
• Posner Cue - Target Paradigm:
Orienting Attention
• Posner Cue - Target Paradigm:
Orienting Attention
• Posner Cue - Target Paradigm:
Orienting Attention
• Posner Cue - Target Paradigm:
X
Orienting Attention
• Posner Cue - Target Paradigm:
Orienting Attention
• Posner Cue - Target Paradigm:
That was a validly cued trial because the
x appeared in the box that flashed
Orienting Attention
• Posner Cue - Target Paradigm:
Orienting Attention
• Posner Cue - Target Paradigm:
Voluntary Orienting
• What is another way to make this paradigm a
voluntary orienting paradigm?
Symbolic Cue
Symbolic cues may orient attention towards another location.
Stimulus cues orient attention to the stimulated location.
Reflexive Orienting
• Attention can be automatically “summoned” to a
location at which an important event has occurred:
Reflexive Orienting
• Attention can be automatically “summoned” to a
location at which an important event has occurred:
– Loud noise
– Motion
– New Object
Transients
• We call this attentional capture
Reflexive Orienting
• The Posner cueing paradigm (with blinking
boxes) confounds reflexive and voluntary
orienting
… in what way?
Reflexive Orienting
• The Posner cueing paradigm (with blinking
boxes) confounds reflexive and voluntary
orienting
• How could we change the Posner cueing
paradigm to make it asses only reflexive
orienting?
Reflexive Orienting
• The Posner cueing paradigm (with blinking
boxes) confounds reflexive and voluntary
orienting
• How could we change the Posner cueing
paradigm to make it asses only reflexive
orienting?
• Make validity 50% (non-informative cue)
Reflexive Orienting
• The Posner cueing paradigm (with blinking
boxes) confounds reflexive and voluntary
orienting
• How could we change the Posner cueing
paradigm to make it asses only reflexive
orienting?
• Make validity 50% (non-informative cue)
• Viewers are still faster and more accurate!
Reflexive Orienting
• Can symbolic cues be reflexive?
Almost never but …
Reflexive Orienting
• Can symbolic cues be reflexive?
Reflexive orienting to direction of eye gaze
Reflexive Orienting
• Potential cues for Reflexive Orienting
– Loud noise
– Motion
– New Object
Transients
• New Objects are powerful attention grabbers!
New Objects Capture Attention
IS THERE AN “H”?
Yantis & Jonides (1990): New-Object Paradigm
Initial scene
viewed for
several
hundred ms
New Objects Capture Attention
IS THERE AN “H”?
New scene:
search for
target letter
H may be
revealed from
an 8 or may
appear as a
new object
Yantis & Jonides (1990): New-Object Paradigm
Reflexive Orienting
• Steven Yantis and colleagues
– Result:
Reflexive Orienting
• Steven Yantis and colleagues
– Result:
Targets are found faster when they are
“new objects” than when they are
revealed from “old” objects
Reflexive Orienting
• Steven Yantis and colleagues
– Interpretation:
The visual system prioritizes in dealing
with visual objects - relatively recent
objects are “flagged” while older objects
are disregarded