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 locations2. 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

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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 cues may orient attention towards another location.Stimulus cues orient attention to the stimulated location.

Symbolic Cue

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

• We call this attentional capture

Transients

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

• New Objects are powerful attention grabbers!

Transients

New Objects Capture Attention

IS THERE AN “H”?

Initial scene viewed for several hundred ms

Yantis & Jonides (1990): New-Object Paradigm

New Objects Capture Attention

New scene: search for target letter

IS THERE AN “H”?

Yantis & Jonides (1990): New-Object Paradigm

H may be revealed from an 8 or may appear as a new object

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