Cognitive Processes PSY 334

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Cognitive ProcessesPSY 334

• Chapter 3 Attention
• July 8, 2003

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What is Attention?

• Attention is the allocation of limited processing
  resources.
• Visual features such as shape, color, texture,
  motion are processed in parallel.
• Serial bottleneck occurs when it is no longer
  possible to process in parallel.
• When does it occur early vs late selection
• How do we select what to attend to?

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How we Experience Attention

• Stream of consciousness -- we learn and remember
  what we attend to.
• Paying attention results in a feeling of mental
  effort.
• Can be directed internally but also pulled
  (attracted) by external events.
• Varies with arousal and fatigue.
• Studied by looking at response competition.

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Auditory Attention

• The response competition comes from having two
  ears.
• Dichotic listening task uses shadowing.
• Two different messages are presented, one to each
  ear. Subjects are asked to speak what they hear.
• People can attend to only one message at a time.

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Three Theories

• Broadbents filter theory
• Treismans attenuation theory
• Deutsch Deutschs late selection theory

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Broadbents Filter Theory

• People do not remember the content of the
  unattended ear.
• Voice or noise, sex, but little else.
• Broadbents filter theory proposed that filtering
  occurs early in processing based on physical
  characteristics (pitch, ear).
• Neural evidence supports the ability to select
  one ear to listen to.
• Cocktail party effect attention switches based
  on content of unattended ear.

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Treismans Attenuation Theory

• Treismans attenuation theory subjects
  deemphasize but not filter out the unattended
  message.
• Meaning switched from one ear to the other.
• Some subjects switch ears even when told not to,
  following the semantic content.
• Semantic criteria apply to all messages, filtered
  or not.

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Late Selection Theory

• Deutsch Deutschs late selection theory the
  limitation is in the response system, not the
  perception.
• Both messages are perceived but only one can be
  shadowed at a time.
• The criterion for selecting what to say can
  change based on ear or meaning.

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Testing the Theories

• Dichotic listening task
• Shadow one message but listen for a target word
  in both ears (tap when heard).
• Late selection theory predicts no difficulty
  hearing the target in either ear.
• Attenuation theory predicts less detection in
  non-shadowed ear.
• 87 detection in shadowed ear
• 8 detection in non-shadowed ear

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Echoic Memory

• Glucksberg Cowen demonstrated that unattended
  information can be kept in an echoic memory
  buffer for brief periods.
• Shadow a message, with digit presented to
  non-shadowed ear.
• 25 of time, is asked immediately after
  presentation, reported hearing the digit.
• 5 of time reported the digit, without cuing
• Unattended material is lost within 5 seconds.

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Visual Attention

• We can choose where to fixate our eyes for
  greatest visual acuity.
• Other portions of the visual field are
  attenuated.
• Visual attention need not be located where the
  eyes are fixed.
• Posner subjects can attend to objects up to 24
  degrees from the fovea.
• Shift of attention precedes eye movement.

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Spotlight Metaphor

• Spotlight can be broad or narrow (degrees of
  visual angle).
• Broad areas processed less well.
• A narrow focal point gives optimal processing but
  it takes time to move the focus to other areas of
  the visual field.
• We move our eyes around a complex visual
  stimulus.
• Neisser Becklens shadowing task.

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Neural Basis of Attention

• Attention consists of enhanced neural response in
  a particular area of the brain.
• The brain is organized topographically.
• By increasing neural activity in a particular
  location, input to that location can be processed
  faster.
• Specific details are higher order properties
  and take longer to recognize.

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Iconic Memory

• Visual sensory input can be remembered for a
  short time up to 5 seconds.
• Retention time varies if a post-exposure field is
  light (1 sec) vs dark (5 sec).
• Following one display with another display
  washes out the first memory (icon).
• Visual sensory information must be attended to
  and processed in order to be remembered longer.

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Sperlings Partial Report

• The purpose of an icon is to retain an image
  until attention can focus upon it.
• How long does the icon last?
• How fast can attention move through it?
• Subjects see an array of letters flashed briefly
  (50 ms), then report them back.
• After the array is gone, a tone is sounded.
• Subjects must report the letters in the row
  corresponding to the tone (high, med, low).