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Lecture 8

PSY270H1 Lecture Notes - Lecture 8: University Of Manchester, Catdog, Dual Code


Department
Psychology
Course Code
PSY270H1
Professor
Gillian Rowe
Lecture
8

Page:
of 11
Lecture 8:
Knowledge: Concepts, Categories, and Category
Specific Impairments, Visual Imagery I
OUTLINE:
Organization of knowledge: concepts and different theories
Organizing categories in our mind and different theories
Semantic knowledge and impairments (i.e brain injury)
Visual Imagery 1
Organization of knowledge: concepts and different theories
Knowledge
oConcepts, categories and network, and category specific impairments. We
acquire it over our life span and is fairly consistent. We won’t know where we
learned it from though. For example, I know that Montréal is a city in Quebec, but
I won’t know where exactly I learned it from.
Concepts
oFundamental unit of symbolic knowledge (mental representation—it must mean
something to us.
oIncludes categories, rules used to organize concepts.
oIncludes schemas and scripts, a framework used to organize concepts.
oA concept is a mental representation of a item and associated knowledge and
beliegfs (cats, tools, furniture)
oWhat do concepts do for us?
Cognitive economy—we don’t have to explain everything in extremem
details, which makes conversation possible and function normally.
Inferences—people infer what we are saying and don’t have to think
about it a lot. Or when reading a novel, the author infers that you know
about a certain concept.
Combine to form complex thoughts
Communication
oThere are Different types of concepts:
Natural concept: occur naturally (E.g., plants, trees, and cats)
Artifact concept: created by humans (eg. Hammers, computers)
There are categories within concepts
Ad Hoc Concepts:
Categories formed with a particular purpose in mind (things you
need to be happy, things you do to please parents vs. Friends,
things you need to write a PSY270 paper)
Vary across individuals, subject matters, time—flexible and just
serve purpose.
Organizing categories in our mind and theories
Categorization: rules to organize concepts
oGroup things into categories (e.g., animals, vehicles, furniture): can get categorized more
finely within that category.
oUse categories to help process new information (e.g., let s know that the animal we just saw
is a cat?)- Example of “washing clothes” dialogue. If they knew what it was about (the
framework) people will understand better.
oHelps us to understand our world—(evolutionary purpose).
oKnowing what category something belongs to provides us with additional information about
it.
Different theories:
oHow do we determine what category something belongs to?
Definitional Approach: Defining Features (Classical view): by checking potential members
against a list of defining criteria?
Examine the features of an item to determine whether it is a particular concept. Must
have a defining feature to be considered a member. Eg. Birds: feathers, wings, fly etc.
Chairs: four legs, a back, and can be say upon etc. But not all do—this poses a
problem.
Problems: Typicality Effect: some things are better examples of a concept than
others. Ex. Robin is a more typical bird than a penguin. It is difficult to specify what are
necessary features, to be able to give enough features that people would be able to
identify.
Prototype Theory: Posner’s dot experiment (perception) (overlaps features with
knowledge).
Abstracted representation of a category containing salient features that are true of
most instances.
Characteristic features which describe what members of that concept are like: monster
prototypes are: scary, pales, have sharp teeth, are evil, an lives in odd places like
coffins, closets or graveyards—you see, vampires, zombies, and the Bogeyman,
whom all fit the prototype well. But the cookie monster doesn’t fit any of these
categories. Prototypes allows us to think outside the box and the exceptions to the
rules.
Deals well with fuzzy concepts. Fuzzy concepts are categorizes that cannot always be
easily defined (eg. Monster, Games)—different types of clouds example. To
categorize, simply compare to prototype.
Categorization by prototype: we determine category membership by comparing to a
prototypical category member. Prototype is average of all members of a category. Ex.
Bird family-similar to prototype. Young children take longer to be able to decide if an
ostrich or penguins are birds. The level of similarity can vary:
o high-prototypicality: member is very similar to prototype
(e.g robin)
oLow-prototypicality: member has only a few similarities
with prototype (e.g. ostrich).
EXPERIMENT: Some category members are better
examples (more prototypical) of a category than others.
Rosch (1975) asked participants to rate (1-7) how
representative particular members were of a specific
category. (Cross-cultural). People do seem to have some
sort of prototype that allows them to make such rating.
EXPERIMENT: Rosch et al (1975): Family Resemblance. Comparison of items within the same
category. List shared characteristics: chair, sofa, mirror, telephone. There are many overlapping