SEMANTIC MEMORY

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SEMANTIC MEMORY
Dr. Cath Mazuro.
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Semantic Memory
Organisation of knowledge - how is it stored in
memory? Categories Concepts.
How do we represent concepts?
Information is not same as knowledge. Semantic
meaning.
Theoretical approaches Classical Prototype
Schemas Scripts
Neuropsychological studies.
Concepts categories in action.
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Organisation of Knowledge. Categories created by
grouping feasible items together. Basic
principles.
Cognitive Economy. Saves space helps avoid
confusion.
Informative. Need to be meaningful.
Dwelling places non-dwelling places?
Naturalness.
Pink hyenas? Cars with no wheels?
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Example
Concept of Dog
Has four legs
Things (i.e. features or attributes) we would
look for in order to identify something as a
dog.
Has fur
Barks
Attacks postman
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Classical View (defining concepts) Eg. Bruner,
Goodnow Austin, (1956) Katz Fodor, (1963)
Collins Quillian, (1969).
Principles
List of attributes (or features).
All are necessary, and jointly sufficient
Boundaries between categories are clear-cut.
All members of a category are equally
representative
Orange - is round, is orange, is juicy, has pips.
Higher order categories Fruit.
Oranges, apples, bananas, grapes.
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Classical view (e.g. Katz Fodor, 1963)
BACHELOR
Dictionary entries Hierarchical tree
Noun
Human
Animal
With an honours degree
Male
Male
young seal when without a mate during breeding
time
young knight serving under the standard
of another knight
who has never married
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Classical -Semantic Network Theory
has skin
can move around
Animal
Superordinate
eats
breathes
Subordinate
Bird
Fish
has fins
has wings
can swim
can fly
has gills
has feathers
is pink
is edible
has long legs
can bite
can sing
swims upstream to lay eggs
cant fly
is dangerous
is yellow
is tall
Canary
Ostrich
Shark
Salmon
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Classical -Semantic Network Theory
Collins Quillian (1969)
Cognitive economy claim. Sentence verification
tasks.
Tested reaction times found category size
effect.
Property sentences
1500 RTs Ms 900
A canary has skin
Category sentences
A canary can fly
A canary can sing
A canary is an animal
A canary is a bird
(Distance in network)
A canary is a canary
0 1 2
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Problems with the Classical View.
Salience. (Conrad,1972). Salmon is pink v
salmon has fins.
Typicality effects. Rosch, (1973) Rips, Shoben
Smith (1973). Robin v Penguin. Tarzan
poor example of bachelor.
Fuzziness. McCloskey Glucksberg, (1978). Tomato?
Concept Instability (Barsalou, 1983, 1989). Frog?
Ad-hoc categories. We create categories as and
when we need them.
Difficult-to-define concepts. Fodor, Garret,
Walker Parkes, (1980). Game?
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Prototype theory (e.g. Rosch, 1978).
Concepts have characteristic attributes.
Object is a member of the concept if there is a
good match between the attributes it has, and
those of the category.
The more attributes shared by other members with
the best example, then the more characteristic it
is of the category.
Categories organised around central
prototypes Similarity is important. No defining
features that are necessary sufficient. Fuzzines
s is fine. Typicality Effects used as evidence.
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Evidence.
Rosch - Typicality Effects.
Typicality Gradients (e.g. Danks Gluckberg,
1980). Sentence verification tasks confirm
existence of prototypes. Response times good
predictors of centrality.
FRUIT VEGETABLE Apple 1.3 Carrot
1.1 Plum 2.3 Asparagus 1.3 Pineapple 2.3 Celery
1.7 Strawberry 2.3 Onion 2.7 Fig 4.7 Parsley
3.8 Olive 6.2 Pickle 4.4
Mervis, Caitlin Rosch (1976) Typical members
are more likely to be mentioned first, when asked
to list members of a category.
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Focal colours. Berlin Kay,(1969). 300 coloured
chips presented to people in foreign
countries. Best examples?
Rosch (1975a) Dani tribe. People with limited
vocabulary still select similar colours.
But biological basis? (Gordon, 1989).
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Problems with Prototype theory.
Not all concepts have prototypical characteristics
Concrete v abstract concepts.
Holland et al, (1986). Relations between
attributes. People know that certain attributes
are more likely to vary than others.
Some attributes/features more predictable than
others!
Ad hoc categories? (eg Murphy
Medin,1985). Context, goals and intentions still
not accounted for.
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Spreading Activation Theory
lada
street
garage
fire engine
gate
house
vehicle
bus
garden
tree
blossom
red
apple
rose
blue
green
Anderson (1983) Collins Loftus, (1975),
Mc.Clelland, (1981) IAC model
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Schemas Scripts.
Are concepts and attributes enough?
Schemas structured knowledge frameworks. Contain
concepts, slots values Episodic and procedural
knowledge Guide and help interpret new knowledge
and situations especially when context is
unclear. (Bartlett, 1932)
Schemas are very broad based guidelines, scripts
more specific (Schank Abelson, (1977). Scripts
schemas for more specific events- People often
fill in parts not mentioned.
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Scripts.
Bower, Black Turner Restaurant script.
Participants listed 20 typical actions - e.g.
go in sit down, look at menu, order meal, eat,
pay bill, leave
73 agreement on sequence.
Verification determined by importance, not
order.
Galambos and Rips (1982). Participants make
rapid decisions about whether or not an action
was part of a script. Rts faster for actions
that WERE part of the script.
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Restaurant Script
Scene 1Enter
Scene 2Order
Scene 3Eat
Scene 4Pay
Ask for bill Get bill Pay bill Tip waiter exit
Go inside Go to table Sit down
Get menu Read menu Choose Order
Get food Eat food
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Neuropsychology
Patients with deficits have impaired ability to
control and monitor thoughts and memories.
Impaired supervisory control, but can function in
daily life.
Social and intellectual function intact.
However -

• What did you have for lunch three days ago?
• Cannot organise autobiographical/episodic
  memories.

• Semantic tasks. Name as many items from a
  supermarket as you can.

Cannot control/inhibit examples items. Can
mention key items, then often repeat.
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Neurological evidence for concepts.
Schwartz, Saffran Marin (1980).
Patient WLP Dementia.
Reading ability intact, comprehension poor.
Cannot match words with pictures.
However, wrong words selected were semantically
similar, e.g. fork spoon. (category retained
things we use to eat).
Coughlan Warrington (1978) Patient EM.
Forced choice decision tasks is a cabbage an
animal or a plant? (superordinate) is a
cabbage green, blue or grey? (subordinate)
Found 28 errors for subordinate 2 errors for
superordinate.
Superordinate more resilient?
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Evidence for Categories.
Dennis (1976) Patient had difficulties only with
body parts.
Warrington Shallice (1984). MTL damage.
Patients can identify inanimate objects, (words
or pictures) but poor at identifying living
things, or foods.
Hart, Berndt Caramazza (1985). Patient could
not identify fruits and vegetables.
Funnell Sheridan (1992), Parkin Steward
(1993). Artefactual?
Familiarity with stimuli? No. of times mentioned?
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Wernickes Aphasia.
Sometimes known as Semantic Aphasia.
Also a centre for reading and writing skills
which have been learned auditorily.
Damage to left superior temporal gyrus leads to
impairments in auditory comprehension.
Patients can speak fluently, though speech devoid
of meaning. Neolistic Jargon. Speech lacks
content, but often grammatically correct.
You know that smoodle pinkered and that I want
to get him round and take care of him like you
want before,. ("The dog needs to go out so I
will take him for a walk.) (NIDCD
2002)
Many patients unaware of deficits.
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Concepts categories in real life.
How are illnesses diagnosed?
How is the Diagnostic and Statistical Manual of
Mental Disorders, (DSM-IV) compiled?
e.g. Psychiatric Diagnoses are categorized by
the Diagnostic and Statistical Manual of Mental
Disorderscovers all mental health disorders for
both children and adults. It also lists known
causes of these disorders, statistics in terms of
gender, age at onset, and prognosis (from
AllPsyc ONLINE, 2002)
Children learning a language?
Eyewitness Testimony? What can go wrong?
Research Methods
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Philosophy (Language Thought)
Abstract, disembodied thought Mechanical
manipulation, the computer metaphor Body -
incidental/abstract Words correspond directly
with what is out there in the world Categories
have certain properties in common.
Experientialism - thought is embodied Thought is
imaginative Reasoning/thought not mechanical No
focus on necessary and sufficient conditions This
philosophy says more about us as humans
Lakoff, G. (1990). Women, Fire and Dangerous
Things What Categories Reveal About the Mind.
Chicago, Chicago University Press. Lakoff, G.
and Johnson, M. (1980) Metaphors We Live By.
Chicago, IL Chicago University Press.