Lecture 8 - Concepts and Categories Flashcards
1
Q
What are categories?
A
- Groups of similar objects in the environment
2
Q
What are concepts?
A
- Representations of categories
3
Q
Why are concepts important?
A
- Allow predictions to be made and to draw inferences, without having to experience them.
- Allow for cognitive economy: single example rather than remembering all instances.
- Allow communication, similarity between people with concepts
4
Q
What are the structure of natural categories?
A
- Superordinate e.g animal
- Basic: level at which you choose to name things e.g dog
- Subordinate e.g border collie
5
Q
What is the best level to summarise categories?
A
- Basic levels, everyone chooses this
6
Q
What are components of basic level categories?
A
- Spontaneous naming
- Large number of unique features, features belonging to some objects but not others
- Acquired first e.g dog first then border collies
- Recognised most rapidly e.g react faster to is this a car than is this a vehicle/jaguar
7
Q
What is the defining attributes theory?
A
- Objects we recognise, we classify them on a set of rules.
- These attributes are individually necessary and sufficient for category membership
8
Q
Support/Issues with DA theory?
A
Support:
- Intuition
- Collins and Quillian Hierarchal model
Issues:
- Definitions are impossible to find e.g how to define a chair
- Some instances are more typical than others e.g rosch with sentence verification and ratings of things e.g robin/ostrich is a bird.
- Boundaries between concepts can be fuzzy
9
Q
What is a study that shows fuzzy concepts?
A
- Asked ppts if a stroke was a disease
- 16 said yes, 14 said no
- A month later, 11 people changed their minds, showing rules are flexible.
10
Q
What is the prototype theory?
A
- Concept represented by single instance or prototype
- Has all characteristic attributes of the category.
- Categorise new thing based on how similar it is to the prototype.
11
Q
Issues with PT?
A
- Single example means info is thrown away about relations between attributes e. small birds are more likely to sing than big birds
- Exp asked people what a shape was more likely to be if the size was in between a coin and pizza, most people thought it was pizza = exemplar theory = pizza has more variability
12
Q
What is exemplar theory?
A
- Assumes you store all examples to form a concept
- Categorisation is based on similarity to exemplars
- Retains category variability information
13
Q
Issues with similarity theories?
A
- Concept combination: how do you make a new category from two other ones
- Ad hoc categories e.g things to take if your house caught fire. Do not share too much physical similarity
- Categorisation is not always based on perceived similarity
