1. Representational Hypotheses in Cognitive Psychology
Psychology 355: Cognitive Psychology Instructor: John Miyamoto 05/18/2016: Lecture 08-3
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2. Lecture probably ends here
Outline
Representational hypotheses - what are they?
The centrality of human language capacity in the theory of cognition
Semantic network models - a very brief discussion
Is there a basic level in human conceptual representations?
Neuropsychological representations of categories and concepts
Lecture probably ends here
Cognitive Theory = { Representational Hypotheses + Processing Hypotheses }
Psych 355, Miyamoto, Spr ‘16

3. Representational Hypotheses in Cog Psych
Assumption: Human perception, memory, language, and reasoning are based on the ability to create, store, retrieve and manipulate a variety of mental representations.
Representational Hypotheses Cognitive Theory = Plus Processing Hypotheses
Mental Representations & Their Uses
Psych 355, Miyamoto, Spr '15

4. Levels of Representation in Language
Theories of human language capacity propose representational hypotheses at many levels.
Articulatory and acoustical phonetics - the study of the muscular coordination in speech and acoustical patterns in the speech signal.
Phonology - the study of the sound structures of languages.
Syntax - theories of sentence structure and its relation to speech context and meaning.
Semantics - theories of the relation between language structure and meaning.
Language-Like Representations in Cognition
Psych 355,, Miyamoto, Spr '16

5. Symbolic Representations in Cognition
The motor theory of speech comprehension: A link between speech production and speech comprehension.
Models of language syntax
Cognitive, computational and/or neuropsych models of language processing with emphasis on sentence structure.
Inference in language use - is it a logic? is it a computer program?
The modeling of human language capacity is a major concern of cognitive science.
cog psych is part of cognitive science; other parts include philosophy, linguistics, computer science, neuroscience, anthropology
Semantic Networks & Connectionist Models
Psych 355,, Miyamoto, Spr '16

6. Semantic Networks & Connectionist Models
SKIM
Semantic networks & connectionist models – two different approaches to modeling concept structure.
Semantic networks & connectionist models use different formalisms.
Spreading activation – activation of some concepts causes activation in associated concepts.
Connectionist models focus on learning concept structure. [This topic will be omitted from Psych 355 this quarter.]
Semantic networks focus on modeling human concept structure without modeling how we learn this structure.
Psych 355 will briefly discuss semantic network models and ignore connectionist models.
Semantic Network Models
Psych 355, Miyamoto, Spr '16

7. Semantic Network Models
Concepts are arranged in networks that represent the way concepts are organized in the mind.
Any specific network model must explain:
what is the relationship between the structure of the network and human thinking or behavior;
what are the rules by which representations are constructed within the model;
how to derive predictions from the model to different aspects of human behavior.
Example of a Semantic Network
Psych 355, Miyamoto, Spr '16

8. Example of a Semantic Network
SKIM
Goldstein Figure 9.12
Collins and Quillian (1969)
Model for how concepts and properties are associated in the mind
Node = category/concept
Concepts are linked
Cognitive economy: shared properties are only stored at higher-level nodes
Exceptions are stored at lower nodes
Inheritance
Lower-level items share properties of higher-level items
Psych 355, Miyamoto, Spr '16

9. Using a Semantic Network to Predict Sentence Verification
Goldstein Figure 9.13 (top) & 9.14 (bottom)
Collins & Quillian (1969)
Measure response time to verify whether sentence is TRUE or FALSE ("sentence verification" or "semantic memory")
Spreading Activation Theory:
Activation is the arousal level of a node
When a node is activated, activity spreads out along all connected links
Concepts that receive activation are primed and more easily accessed from memory
SKIM
Summary re Semantic Networks
Psych 355, Miyamoto, Spr '16

10. Summary re Semantic Network Models
Concepts are represented as nodes in a semantic network.
What do semantic network models (SNM's) do?
SNM's explain the relationship between the network structure and human reasoning and behavior.
SNM's yield predictions for cognitive experiments like semantic memory experiments, categorization judgments and causal inferences.
SNM's can be part of a learning model that predict how a learner learns new concepts and conceptual relationships.
There are many different SNM's that are devised for different research problems. They tend to be complicated.
Reminder: Cat Picture - Transition to Basic Levels in Categorization
Psych 355,, Miyamoto, Spr '16

11. Knowing the Category Provides a Lot of Information
Is There a Basic Level of Categorization?
Psych 355, Miyamoto, Spr '16

12. Is There a Basic Level in Categorization?
Categories can often be arranged from higher-level superordinate categories (more inclusive) to lower-level subordinate categories (less inclusive; more specific).
Eleanor Rosch asked: Is there a basic level of categorization at which we habitually categorize the objects in our experience?
Basic Level Versus Superordinate Level: Amount of Feature Sharing
Psych 355, Miyamoto, Spr '16

13. What Defines the Basic Level of Categorization?
Hypothesis: The basic level is the highest level at which category members share many features within the category while also being very different from objects in other categories at the same level.
Two Factors that Determine the Basic Level:
Within a basic level category, objects share many features with each other.
Between different categories at the basic level, objects are very different from each other.
Basic Level Versus Subordinate Level: Amount of Feature Sharing
Psych 355, Miyamoto, Spr '16

14. What Defines the Basic Level of Categorization?
Hypothesis: The basic level is the highest level at which category members share many features within the category while also being very different from objects in other categories at the same level.
Two Factors that Determine the Basic Level:
Within a basic level category, objects share many features with each other.
Between different categories at the basic level, objects are very different from each other.
Same Slide Without Emphasis Rectangles
Psych 355, Miyamoto, Spr '16

15. What Defines the Basic Level of Categorization?
Hypothesis: The basic level is the highest level at which category members share many features within the category while also being very different from objects in other categories at the same level.
Two Factors that Determine the Basic Level:
Within a basic level category, objects share many features with each other.
Between different categories at the basic level, objects are very different from each other.
Information Gain at Different Levels of Categorization
Psych 355, Miyamoto, Spr '16

16. Information Provided by Categorizations at Different Levels
If you categorize something at the superordinate level, e.g., "furniture," instead of at the basic level, e.g., "table," you lose a lot of information about the object.
If you categorize something at a subordinate level, e.g., "kitchen table," instead of at the basic level, e.g., "table," you don't gain a lot of information about the object.
Concrete Example with Images of a Bull Do and a Pickup Truck
Psych 355, Miyamoto, Spr '16

17. What Is It? Possible Answers Possible Answers An animal A vehicle
Superordinate level
A vehicle
Superordinate level
A dog
Basic level
A truck
Basic level
A bulldog
Subordinate level
A pickup truck
Subordinate level
Return to Diagram Showing Superordinate, Basic & Subordinate Levels
Psych 355, Miyamoto, Spr '16

18. Information Provided by Categorizations at Different Levels
The basic level is the level at which we typically categorize everyday objects.
We are capable of categorizing objects at superordinate or subordinate levels, if required to do so by a situation or task.
Criteria for Basic Level: Feature Listing
Psych 355, Miyamoto, Spr '16

19. Behavioral Criteria for Basic Level Categories
Skim
Criterion 1 (Feature-Listing): Ask subjects to list features of objects in a category
Category Name = (fill in the blank, e.g., “furniture” or “chair”)
Instruction: “List as many characteristics or attributes that you can think of which describe the object.”
Examples
Categorization: FURNITURE
“List as many characteristics or attributes that you can think of which describe furniture.”
Categorization: CHAIR
“List as many characteristics or attributes that you can think of which describe chairs.”
Categorization: ARMCHAIR
Superordinate Level
Basic Level
Subordinate Level
The instructions for the feature listing task were taken from Exp 1 of Tanaka & Taylor (1991), cited in the notes to the next slide.
Behavioral Criteria: Basic Level has Greatest Gain in Features
Psych 355, Miyamoto, Spr '16

20. Behavioral Criteria for Basic Level Categories (cont.)
Skim
Criterion 1 (Feature-Listing): Ask subjects to list features of objects in a category
Category Name = (fill in the blank, e.g., “furniture” or “chair”)
Instruction: “List as many characteristics or attributes that you can think of which describe the object.”
Characteristic of the basic level:
Superordinate level – relatively few features are listed (not many features of “furniture”)
Basic level – many features are listed (Many features associated with “chairs”)
Subordinate level – may have more features than the basic level but the increase is relatively small (Features listed for “armchair” are not many more than features listed for “chair”)
The instructions for the feature listing task were taken from Exp 1 of Tanaka & Taylor (1991), cited in the notes to the next slide.
Behavioral Criteria: Free Naming
Psych 355, Miyamoto, Spr '16

21. Behavioral Criteria for Basic Level Categories (cont.)
Skim
Criterion 2 (Free Naming): Ask subjects to name a picture of an object
Instruction: “What would you call this?” [show image of an object]
Characteristics of the Basic Level:
The basic level is the most commonly used category label.
Example
Show subject a picture of an armchair.
The response “chair” is more likely than the response “furniture”. The response “chair” is more likely than the response “armchair”.
The instructions for the feature listing task were taken from Exp 1 of Tanaka & Taylor (1991), cited in the notes to the next slide.
Behavioral Criteria: Category Verification Time
Psych 355, Miyamoto, Spr '16

22. Behavioral Criteria for Basic Level Categories
Skim
Criterion 3 (Category Verification): Measure response time for deciding whether an image is an example of a given category
Examples
1st subject hears “FURNITURE”
Next subject sees picture of an armchair.
Correct response = TRUE
1st subject hears “CHAIR”
1st subject hears “ARMCHAIR”
Superordinate Level
Basic Level
Subordinate Level
The instructions for the feature listing task were taken from Exp 1 of Tanaka & Taylor (1991), cited in the notes to the next slide.
Behavioral Criteria: Category Verification Time – Basic level Fastest
Psych 355, Miyamoto, Spr '16

23. Behavioral Criteria for Basic Level Categories
Skim
Criterion 3 (Category Verification): Measure response time for deciding whether an image is an example of a given category
Characteristic of the Basic Level: Categorization decisions are fastest at the basic level.
1st subject hears “FURNITURE”
Next subject sees picture of an armchair.
Correct response = TRUE
1st subject hears “CHAIR”
1st subject hears “ARMCHAIR”
Superordinate Level
Basic Level
Subordinate Level
The instructions for the feature listing task were taken from Exp 1 of Tanaka & Taylor (1991), cited in the notes to the next slide.
Slower Categorization Response
Fastest Categorization Response
Fastest Categorization Response
Slower Categorization Response
Behavioral Criteria: Summary
Psych 355, Miyamoto, Spr '16

24. Summary: Behavioral Criteria for Basic Level Categories .
Skim
Criterion 1 (Feature-Listing)
Criterion 2 (Free Naming)
Criterion 3 (Category Verification)
The instructions for the feature listing task were taken from Exp 1 of Tanaka & Taylor (1991), cited in the notes to the next slide.
Expert Versus Non-Experts
Psych 355, Miyamoto, Spr '16

25. The Basic Level May Not Be the Same for Experts & Non-Experts
Tanaka and Taylor (1991): Bird experts use specific bird species, e.g., "eagle", "hawk", etc., as if they are the basic level. For the average person, "bird" is basic level, but not for bird experts.
Experts
Non-Experts
Tanaka, J. W., & Taylor, M. (1991). Object categories and expertise: Is the basic level in the eye of the beholder? Cognitive Psychology, 23,
basic
specific
Same Slide Without Emphasis Rectangles
Psych 355, Miyamoto, Spr '16

26. The Basic Level May Not Be the Same for Experts & Non-Experts
Tanaka and Taylor (1991): Bird experts use specific bird species, e.g., "eagle", "hawk", etc., as if they are the basic level. For the average person, "bird" is basic level, but not for bird experts.
basic
specific
There May Be Cultural Differences in Categorization
Psych 355, Miyamoto, Spr '16

27. There can be systematic cultural differences in category knowledge
Medin et al. compared Native American (Menominee Indian) and Euro- American fish experts (fisherman).
Euro-American experts tended to sort fish into goal-related categories, e.g., game fish and non-game fish.
"Native American fish experts ... tended to sort ecologically and were more likely to see positive and reciprocal ecological relations," e.g., fish that live together or live in predator-prey relations.
Itza Maya in Guatemala categorize birds at a lower level than do typical Americans.
Basic level for Itza Maya is the subordinate level for Americans.
E.g., Itza Maya would say "red hawk" where an American would say "bird."
Summary re Category Structure
Psych 355, Miyamoto, Spr '16

28. Summary re Category Structure
The "basic level" of categorization is the level of category structure that is usually most useful for members of a given culture.
The objects that are grouped together in a basic level category ....
share many properties with other objects in the category, i.e., different chairs share many important properties with each other, and ....
differ in important ways from objects in other categories at the same level, e.g., chairs differ in important ways from tables, lamps, cars, etc.
The basic level can differ between experts and non-experts in a domain, or between members of different cultures.
What Is the Neural Representation of Category Knowledge?
Psych 355, Miyamoto, Spr '16

29. Wednesday, May 18, 2016: The Lecture Ended Here
Psych 355,, Miyamoto, Spr '16