12/7/08
What is Sex?
How is Knowledge Stored?
•  Defining-Attribute Approach --> Dead Theory
–  Each concept has specific features which define it
–  Goal: Determine a set of features that can define
each concept
–  Husband: +male, + married
–  Bachelor: +male, -married
–  Wife: -male, +married
–  Spinster: -male, - married
•  Problems
–  Concepts are often not this rigid
“Quebec is a nation within a united Canada”
•  Debate over the meaning of “nation”
•  Clinton denied having "sexual relations" with
Lewinsky.
•  During the deposition, Clinton was asked
"Have you ever had sexual relations with
Monica Lewinsky, as that term is defined in
Deposition Exhibit 1, as modified by the
Court?"
•  Clinton answered "I have never had sexual
relations with Monica Lewinsky."
•  Clinton later stated that he believed the
agreed-upon definition of sexual relations
excluded his receiving oral sex.
•  Results:
–  President Clinton was held in contempt of
court by judge Susan D. Webber Wright.
–  His license to practice law was suspended in
Arkansas and later by the
United States Supreme Court.
–  He was also fined $90,000 for giving false
testimony which was paid by a fund raised for
his legal expenses.
The Problems with Concepts
•  Feature theory fails because it’s virtually impossible to
set up strict definitions for every single object
–  Boundaries seems fuzzy and undefined
•  Idiosyncrasies are difficult to research
–  Perception studies typically need about 8 participants
–  Social Psychology studies typically need from 40-100.
•  Result:
–  Most Research has focused on explaining basic-level concepts
–  There is general assumption that people do have a certain level
agreement about what a dog is, what a cat is
–  New Mission
•  How is this information stored in memory?
•  Best Possible Model
–  Smallest and Simplest as Possible (Parsimony)
–  Contain all the associated Knowledge
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12/7/08
The Structure of Knowledge: Hierarchical Organization
Semantic Memory
Teachable Language Comprehender (1969)
Cognitive Economy
Earliest Model of Knowledge in Semantic Memory
•
Super-ordinate
-animals
•
•
Basic Level
-dog
•
•
•
Sub-ordinate
-poodle
Reasons the previous theory died
•  The found category difference probably reflects a frequency
difference
–  We typically think more about a canary singing rather than whether is
flies or has skins
–  Faster to remember details more closely associated with that object
•  Further problem is the semantic distance between levels is
seen as equal
–  “Is a canary a bird?” < “Is an ostrich a bird?”
–  “Is a cow an animal” < “Is a cow a mammal?”
•  Require a model that incorporates these differences in
semantic distance
•
Spread of
Activation Model
Features at the top level
separate large concepts
–  Animals, furniture,
fruit
Features at one level are
assumed to be generally
true for the concepts at
lower levels
The same feature isn’t
stated twice
–  A Nech is a bird,
what can it do?
Exceptions can be
specified for a specific
concept
Does a canary have
skin?
Canary can:
–  sing<fly<skin
Canary is a:
–  Canary<bird<animal
•  Keep the notion that things
are associated
•  Remove the notion of
hierarchy
•  Concepts are connected to
eachother by different
lengths
•  Subthreshold activation
accumulates in the nodes
related to the activated
node
•  Explains Priming!
–  Lexical Decision Task
•  Is it a word: bunner, butter
•  Bread-Butter vs. Doctor-Butter
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12/7/08
Knowledge Requires a lot of Connections
•  Semantic Networks is currently the dominate approach
•  Hierarchy is removed to explain semantic relatedness and the knowledge
of attributes
•  Some (e.g. Baddeley) argue it’s too big and not parsimonious
Understanding Connectionist Models
Idea: Recognising an object means
recognizing the parts within an object
•  Recurrent idea in cognitive psychology
How to Identify a written
word?
•
•
•
•
•
•
Breaking-down the word
1. The word itself
2. The letters within the word
Now, break-down the letters
3. The different shapes in the letters
Therefore, to understand a word, you need:
–  The word
–  The letters in the word
–  The features (shapes) in the letters
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12/7/08
Demon Theory
Cohort Model: Hearing the Word
•  “cat”
•  Selection is based on constant narrowing
nothing
Babe
Baby
Bib
Bird
Catch
Can
Cast
Cook
Chirp
Cat
Gone
C...
Can
Cast
Cook
Chirp
Cat
Ca . . .
Can
Cat
cast
Cat . . .
Cat
SERIAL BECOMES PARALLEL
 MAJOR MODERN
THEORETICAL SHIFT
 DIFFERENT LEVELS
 BI-DIRECTIONAL
 LEVELS ARE
CONNECTED TO
EACHOTHER
 ALL ACTIVATED AT THE
SAME TIME
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12/7/08
Written word vs. Heard word
•  INTERACTIVE
INTERACTION
MODEL
Visual Processor
•  TRACE MODEL
Auditory Processor
Phonemes
Phonetic features
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