Concepts and Categorization (CH. 9) Flashcards
What is a Concept?
- Mental representation of things
- The building blocks from which all knowledge is created
- Allow us to categorize, and apply knowledge
The Classical View of Concepts
Concepts are merely lists of necessary and sufficient conditions: Every object with properties A, B, C, and D belongs to category Y, and every object that belongs to category Y has properties A, B, C, and D
Problems with the Classical View
Ludwig Wittgenstein highlighted how hard it is to give formal definitions to human concepts (e.g., what are the necessary and sufficient conditions for defining the concept of “game”?)
McClosekey & Glucksberg (1978)
Studied how people inconsistently form boundaries between categories. The main takeaway from this study is that the boundaries between categories are not well defined or “fuzzy”
Elanor Rosch
Members of a category differ in terms of how well they represent the category as a whole
What is Family Resemblance?
The idea that members of a category (e.g., all dogs, all games) resemble one another. In general, family resemblance relies on some number of features being shared by any subset of category members, even though these features may not be shared by all members of the category. Therefore, the basis for family resemblance may shift from one subset of the category to another
What is a Prototype?
A single “best example,” or average, identifying the “center” of a category
What is Typicality?
The degree to which a particular case (an object, situation, or event) is typical for its kind
Rips (1975) Typicality and Generalization
People are more likely to generalize attributes from typical category members to atypical, than the reverse
What is a Typical Group?
Typical mammals paired with aversive shock during conditioning phase
Atypical Group
Atypical mammals paired with aversive shock during conditioning phase
Dunsmoor & Murphy (2014) Typicality and Conditioned-Fear Generalization
If we learn fear-conditioning for any object in a category, then we will express fear or anxiety if we are shown pictures or images of objects that are more typical in the category of the fear-conditioned object
What is Prototype Theory?
- Concepts are specified by a central member that possess all of the characteristic features of the concept
- Central member is NOT an exemplar. Likely doesn’t exist in real world
Posner & Keele (1968) Testing Prototype Theory
Prototype should be easy to categorize, even if never seen. The findings were that participants were able to correctly categorize old exemplars the quickest, prototype exemplars the second fastest, and new exemplars the slowest
Testing Prototype Theory: What are the Phases?
Training Phase: repeatedly shown numerous distortions of each prototype and instructed to categorize
Test Phase: shown old exemplars, new exemplars, and each prototype and asked to categorize
What is Sentence Verification Task?
An experimental procedure used for studying memory in which participants are given simple sentences (e.g., “Cats are animals”) and must respond as quickly as possible whether the sentence is true or false
What is Production Task?
An experimental procedure used in studying concepts, in which the participant is asked to name as many examples (e.g., as many fruits) as possible
What is Rating Task?
A task in which research participants must evaluate some item or category with reference to some dimension, usually expressing their response in terms of some number. For example, they might be asked to evaluate birds for how typical they are within the category “birds,” using a “1” response to indicate “very typical” and a “7” response to indicate “very atypical”
What is Anomia?
A disorder, often arising from specific forms of brain damage, in which the person loses the ability to name certain objects
What is the Hub and Spoke Model?
A proposal for how concepts might be represented in the brain, with tissue in the anterior temporal lobes serving as the “hub” – a brain location that connects and integrates information from many other brain areas. The “spokes” represent more specific elements of the concept – with (for example) visual information relevant to the concept stored in visual areas; relevant action information stored in motor areas; and so on
What is Exemplar Theory?
- We do not form a prototype; individual exemplars are stored in memory
- Categorization is based on the similarity between a new item and stored exemplars
- Nosofsky (1992) = Generalized Context Model
- Hintzman (1986) = Multiple Trace Memory Model
What are the Differences Between Exemplar and Prototype Theory?
- When faced with a new object, the prototype theory posits that we perform one computation where we measure or decide on how similar the new object is to the prototype
- When faced with a new object, the exemplar theory posits that we perform numerous computations where we measure or compare how similar the new object is to all instances of dogs in our memory pool
How are Concepts Organized?
Hierarchically; not just as a network
What is Transitivity?
All dogs are mammals, and all mammals are animals, so all dogs are animals
What is Property Inheritance?
Lower level categories inherit higher level properties, but not vice versa
