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Update on Schedule

• You will NOT be responsible for
• Chap 8 (Time Place)
• Chap 9 (pp. 192 200)
• Chap 10 (Models)

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Lecture 14 Psyco 350, A1Fall, 2006

• N. R. Brown

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Outline

• Implicit Memory Real-World Estimation
• Semantic Memory Priming

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Brown Siegler (1992) Method

• Materials 100 countries
• Participants 24 CMU undergrads
• Tasks
• Rate knowledge
• Estimate population

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Brown Siegler (1992) Results

• Important results
• As predicted, R(est w/ know) quite high (.58)
• R(est w/know) .58 gtgt R(est/true) .41
• Interpretation
• pop-estimates based in availability-base
  intuitions

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Availability Population Estimation

• Interpretation
• pop-estimates based in availability-base
  intuitions
• An Alterative Interpretation
• People hold preexisting beliefs about the size of
  well-known countries.
• These beliefs are biased by media coverage.
• People infer that unknown countries are small.

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Availability Population Estimation

• People can and do justify their estimates with
  reference to task relevant knowledge.
• Size categories are often mentioned.
• Comparisons w/ other countries also occur
• Key question
• Are size categories retrieved or inferred?

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Brown, Cui, Gordon (2002)

• Aim Determine whether population estimation is
  sensitive to priming, as Availability account
  predicts.
• Method
• Phase 1 rate knowledge
• 52 countries (primed set)
• Phase 2 estimate populations
• 52 primed countries 52 unprimed countries
• primed unprimed sets matched for estimated
  pop, rated kn, actual pop, actual area region

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Brown et al. (2002) Results

• Availability Prediction Primed gt Unprimed
• Results
• Primed 23.3 million
• Unprimed 21.2 million
• ? 2.1 million
• ? 10
• Interpretation
• knowledge ratings ? availability/fluency in
  primed set
• Availability/fluency influenced estimation
  process

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Another Example Fatality Estimates

• Task How many Canadians died of CauseX last
  year?
• Results
• reasonable correlation between estimated true
  fatality rate.
• Availability Bias holding true frequency
  constant, more vivid causes elicit ? estimates

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Another Example Fatality Estimates

• Task How many Canadians dies of CauseX last
  year?
• Results
• reasonable correlation between estimated true
  fatality rate.
• Availability Bias holding true frequency
  constant, more vivid causes elicit ? estimates

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Importance of Availability

• Importance of availability differs across tasks.
• __________________________________________________
  _________________________________________
• Determinants
• actual/perceived correlation between propx and
  memory
• quantity credibility of competing information
• __________________________________________________
  ________________________________________

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Importance of Availability

• Judgment/estimation tasks that are (sometimes)
  display an availability bias
• recency (dates, recognition), truth, fatality
  rates, frequency, probability, corporate sales,
  wealth, population
• Judgment/estimation tasks that do not display an
  availability bias
• age, distance, area, latitude, longitude

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Summary Implicit Memory Judgment

• Prior exposure (priming) facilitates subsequent
  processing (increased fluency).
• People are sensitive to differences in fluency.
• Fluency/availability (sometimes) treated as
  important cue to the value of target property.
• This happens when
• prop x correlates w/ memory
• other task-relevant information
  sparse/non-predictive

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Summary Implicit Memory Judgment

• Use of fluency/availability in judgment often
  produces biased performance
• Reason many factors impact availability.
• For example cultural physical distance,
  economic power, group conflict affect rated
  knowledge, but do not necessarily correlated w/
  actual population

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Semantic Memory Original Definition

• Semantic memory is the memory necessary for the
  use of language. It is a mental thesaurus,
  organized knowledge a person possesses about
  words and other verbal symbols, their meaning and
  referents, about relations among them, and about
  rules, formulas, and algorithms for the
  manipulation of these symbols, concepts and
  relations. (Endel Tulving, 1972, p. 36)

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Contents of Semantic Memory

• We know many, many things
• word meanings (lt 20K), geography, history,
  sports, pop culture, genealogy, social relations,
  biological facts, etc, etc
• Most of this knowledge
• easily readily accessed
• decontextualized

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Semantic Memory Important Issues

• How is complex information
• acquired, revised, represented, organized,
  accessed, manipulated.
• Some basic elements are understood in a general
  way.
• semantic networks
• spreading activation
• schemata/scripts
• Potential building blocks for a more complete
  understanding of the psychology of complex
  knowledge.

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Semantic Networks I Collins Loftus (1975)

• Semantic memory is organized as a network of
  interrelated concepts
• Each concept is represented as a node
• Concepts are linked together by pathways
• Length of pathways reflects degree of semantic
  relatedness/ associative strength
• Concepts close in meaning / highly related (e.g.,
  red, fire) stored close together.
• Unrelated concepts (red, street) are stored far
  away

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An Example of a Semantic Network
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Spreading Activation Semantic Networks

• Accessed node is a source of activation
• Activation spreads from source to related nodes.
• The amount of activation received by a given node
  is a function of path length.
• The more active a concept is, the more readily it
  will be retrieved.
• Implication Retrieving a given concept should be
  easier when it is proceeded by a related concept
  than when it is not.

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An Example of a Semantic Network
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Semantic Priming

• Implication of spreading activation account
• A given concept should be primed responded to
  more rapidly/accurately when it is preceded by
  a related concept than when it is not.
• Therefore, lexical decisions should be faster
  when target preceded by related word than when
  not.

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Semantic Priming Meyer Schvaneveldt (1972)

• An early demonstration of Semantic Priming
• Task Lexical Decision -- with word pairs
• Both items are word ? Yes
• One item is a non-word ? No
• Both items are non-words ? No

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Semantic Priming Meyer Schvaneveldt (1972)

• Stimuli
• Associated word pairs nurse-doctor
• Unrelated word pairs bread-doctor
• word non-word bread-treb
• non-word word treb-bread
• non-word non-word treb-manty

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Meyer Schvaneveldt (1972) Results

• Main Finding
• word-word pairs associated RT lt unassociated RT

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Spreading Activation

• Spreading activation assumed automatic.
• Do expectancies affect semantic access?
• Can activation be control?

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Neely (1977)

• Basic Premises 2 components to priming
• Automatic component
• fast, effortless, unaffected by
  intention/expectation
• Controlled component
• Attentional, Slow, Effortful,
• Benefits (if correct)
• Costs (if incorrect)

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Neely (1977)

• Goal Contrast automatic controlled priming
• Task
• Lexical Decision -- Timed Word/Non-word Decision
• Trial
• Prime ? Target ? Response
• SOA RT
• SOA Stimulus Onset Asynchrony

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Neely (1977) Design

• Prime-Target
• Expectation X Relation X SOA
  .
• No Shift 250 msec
• Shift 400 msec
• 700 msec
• 2000 msec
• see next slide

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• No Shift Trials See Bird as prime expect a bird
  name as target.
• 1. Neutral XXXX -- robin
• 2. No Shift BIRD -- robin
• 3. Shift (unexpected) BIRD -- arm
• Shift Trials See Building as prime, expect a
  Body Part as target.
• 1. Neutral XXXXX -- window
• 2. No Shift BUILDING -- window
• 3. Shift (expected) BUILDING -- leg
• 4. Shift (unexpected) BUILDING -- robin

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• No Shift Trials See Bird as prime expect a bird
  name as target.
• 1. Neutral XXXX -- robin
• 2. No Shift BIRD -- robin 80 primed trials
• 3. Shift (unexpected) BIRD -- arm 20 primed
  trials
• Shift Trials See Building as prime, expect a
  Body Part as target.
• 1. Neutral XXXXX -- window
• 2. No Shift BODY -- leg 10 primed
  trials
• 3. Shift (expected) BODY window 80 primed
  trials
• 4. Shift (unexpected) BODY robin 10 primed
  trials

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Neely (1977) Results

• A Priming Effect Neutral Trials - Primed Trials
• Two Type of Priming Effects
• Facilitation Effects -- Positive Priming
• Priming effect is positive -- Neutral gt Primed
• Inhibition Effect -- Negative Priming
• Priming effect is negative -- Neutral lt Primed

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Neely (1977) Results NO Shift Expected

• No-shift, same-category pairs (Bird-robin)
• Substantial facilitation at all SOA.
• 2. Shift, different-category pairs (Bird-arm)
• Inhibition increases with SOA

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Neely (1977) Results Shift Expected

• 1. Expected Shift (BODY door)
• Facilitation increases with SOA
• 2. No-shift, same-category (BODY -- heart)
• Facilitation at smallest SOA
• Increasing inhibition at longer SOAs

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Neely (1977) Results Shift Expected

• 1. Expected Shift (Building-leg)
• Facilitation increases with SOA
• 2. No-shift, same-category pairs
  (Building-window)
• Facilitation at smallest SOA
• Increasing inhibition at longer SOAs
• 3. Shift to unexpected category (BODY - robin)
• Inhibition at all SOAs
• Inhibition increases with SOA

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Neely (1977) An Explanation

• 1. Automatic Spreading Activation
• Originates at prime, spreads to related concepts,
  decays rapidly.
• 2. Attention required to maintain activation over
  longer SOAs.

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Neely (1977) An Explanation

• 3. Focusing attention on one category
• facilitates (primes) processing of category
  members
• interferes with the processing (reading/word
  recognition) of items from other categories

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Neely (1977) An Explanation

• 4. In the Shift-Expected condition, subjects
  shift attention to maintain attention for cued
  category
• It takes time to shift attention to new category.
• Once attention is shifted, focus is on the new
  category.

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Neely (1977) An Explanation

• Shifting categories takes times.
• Maintaining focus on indicated category
• facilities processing of focal category members
• reduces attentional resources required to read
  decide whether letter string is a word.

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Semantic Networks Priming

• Semantic Network
• general knowledge representation
• based on relatedness, meaning-based similarity
• Spreading Activation
• automatic consequence of processing a related
  information
• preparation for encountering the expected
• Activated concepts sometimes equated w/
  consciousness focal elements of WM (Cowan)