Things To Do Today

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Things To Do Today

• Shower
• Dress
• Eat
• Take the dog out
• Go to work
• Exercise
• Read

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The Central Executive
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Definition

• The central executive presides over the
  operations of working memory. It is the
  processor that allocates resources, governs
  attentional processes, and adjusts goal
  priorities moment by moment. (Jonides, 1995)
• Strongly associated with the Frontal Lobes

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Phineas Gage
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Components of the Central Executive

• Planning and Coordination of Complex Behavior
• Goal orientation
• Focus attention

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Goal Orientation

• Our actions are not aimless we have goals
• Goals can range from looking at a picture to
  telling a story
• The ability to form a coherent plan is
  compromised after damage to the prefrontal lobe
• General memory and IQ are not effected by damage
  to the prefrontal lobe

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Duncan (1995)

• Three components for successfully executing an
  action plan
• Identify the goal and develop subgoals
• Consequences must be anticipated
• Identify the requirements to achieve the subgoals
• One can use all aspects of phonologic loop and
  Sketchpad to do this

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Example of an Action Hierarchy
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Example (frontal lobe damage)

• Frontal lobe patients were asked to go shopping,
  keep an appointment at a given time, and collect
  four pieces of information
• All patients messed up somewhere along the line
• When given a time limit to complete multiple
  tasks, all the subjects would get stuck on one of
  the beginning tasks

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What Causes Failures in Goal Orientation?

• Deficits in working memory (one of the
  subsystems)
• Linking memories to their affective consequences
  (if A then B, if B then C...)
• Holding the goal in memory and making adjustments

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Norman and Shallice (1986)Model for Goal
Orientation

• Selection of an action is a competitive process
• Cued schemas are the bases of our behavior
• Contention Scheduling
• SAS ensures that behavior is flexible

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Supervisory Attentional System

• Responsible for favoring certain schema to
  reflect the demands of the situation
• Situations may include
• Where an incorrect response is likely to occur
  through normal contention scheduling
• We lack a routine procedure for creating an
  appropriate response

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Focus Attention

• Attention must be allocated to complete a task
• PET study of visual attention subjects must
  selectively attend to a visual feature (color,
  motion, shape) or monitor changes in all three
  features simultaneously
• The selective attention activated specific areas
  and divided attention activated the anterior
  cingulate cortex

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Hypothesized System
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Anterior Cingulate and SAS

• The function of attention control by the anterior
  cingulate conforms to what one would attribute to
  an SAS
• As tasks become easier and less attention is
  needed, activity in the anterior cingulate
  becomes less (as shown by PET)

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Time Course of Attention and Working Memory

• Activation in the anterior cingulate is found
  around 180 msec
• 30 msec later the lateral prefrontal cortex is
  activated
• Around 400 msec later posterior regions of the
  brain associated with a specific stimulus are
  activated

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What is happening?

• The cingulate allocates attentional resources
  then establishes a node in the prefrontal cortex
  to hold representations retrieved from the longer
  term representations in the posterior cortex
• As processing spreads through the posterior
  cortex irrelevant associates must be inhibited

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What Happens When Errors are Made?

• When people make errors the cingulate becomes
  active
• When people are not aware of the error the
  cingulate does not activate
• One might say that the SAS detects an incorrect
  schema being used and attempts to gather
  resources to fix the problem (too late)

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Summary

• The Central Executive is not a memory system in
  itself
• The Central Executive coordinates subsystems
  (phonological sketchpad)
• Incorporates all memory information
• Allocates attention to complete tasks

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Attention Memory

• it is the taking possession by the mind.
  (William James, 1842-1910)

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Importance of Attention in Memory

• In terms of working memory, attention is used to
  focus on a task in order to complete it (SAS)
• Attention helps determine perceptual selection
• In terms of learning, attention greatly increases
  ones chance of encoding information

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Attention and Perceptual Selection

• How do we focus on a specific voice in a noisy
  room?
• Is all the information from the noisy room
  available in memory or is it limited?
• Experiment Dichotic Listening (dual task)
• Competing speech input to the two ears
• Subjects would shadow one and ignore the other

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Shadowing Results

• Subjects could not remember the details for the
  speech in the unattended ear (no unattended
  speech effect)
• Thus it seemed that attention was required for
  learning and memory
• However, if information to the unattended ear was
  important (name), subjects could remember it
• Thus it seemed that all information was available
  regardless of attention (unattended speech
  effect)

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Early- Vs. Late-Selection Theories

• To what extent are supposedly ignored signals
  retained in memory
• Early Selection - a stimulus does not need to be
  encoded before it is selected or rejected
• Late Selection - attended and ignored inputs are
  processed equivalently

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Final Answer?

• This is likely to remain an intriguing classic
  problemit is not clear that it will be of direct
  relevance tothe Central Executive (Baddely)
• I think there is a direct relevance to the
  Central Executive

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Limited Capacity

• We can overload the system
• We can not simultaneously process multiple inputs
  if there is a high information load, so we must
  make decisions about what to process next
• Thus information load can effect processing (the
  higher the load the earlier the selection)

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Example

• When your name is mentioned in the unattended ear
  during a Shadowing Task you can remember hearing
  it (low load)
• What if what you were focusing on was a life and
  death situation, would you still remember hearing
  your name? (high load)

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Neuroimaging Results

• Descending projections from attentional control
  systems affect the excitability of neurons coding
  the features of the to-be-attended or ignored
  stimuli.
• The degree of excitability of neurons depends on
  how much attention is being allocated by the
  Central Executive

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Attention and Learning

• Basic Premise - If the task is novel it takes
  more attention
• Attentional Effects - Massed presentations
  habituate learners (fail to register all
  aspects). Therefore, when there is an interval
  between presentations, certain stimulus aspects
  appear novel (more attention), thus leading to
  deeper processing

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Is Attention Necessary for Learning?

• Implicit Learning involves learning without
  intention or awareness
• Learning Rules Artificial Grammar
• PVPXVPS (lawful) PVTT (unlawful)
• There is still a great deal of debate about
  whether this occurs or not

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What Happens When Attention Fails?

• Baddely describes this in terms of vigilance
• So far it seems that if attention fails we can no
  longer complete tasks
• Example - fatigue leads to a loss of attention
• Tasks that are vulnerable are those that require
  more use of STM (studying)
• Tasks that do not rely a great deal on STM seem
  to be less vulnerable

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Is Attention Necessary for Completing a Task?

• No, tasks can be completed automatically
• One can drive a car or walk to class talking on a
  cell phone
• Basic definition - an absence of interference
  between the automatic process and other
  concurrent activity
• Shallice (1985) said that no matter how automatic
  a process is there is at least a 10 interference

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Summary

• Attention influences what we encode and what we
  learn
• Attention can cause information to be selected
  either early or late in processing
• Attention is very helpful in learning but may not
  be necessary
• Attention is reduced when tasks become automated