Midterm 3 Flashcards
What is a concept
- mental representation of things
- building blocks from which all knowledge is created
- allow us to categorize and apply knowledge
Exemplar
one object that is a part of a category
e. g. exemplar: gryph category: mascots
- more flexible
- provide information about category variability
Classical view of concepts
- philosophical
- concepts can be defined by conditional statements usually about features
- concepts are lists of necessary and sufficient conditions
- e.g. every object with properties A, B, C, D belongs to category Y and every objects that belongs to category Y has properties A,B,C,D
Problems with the classical view
- applying concepts to human mind it starts to break down becuase faily common concepts do not have a classical definition
e.g. games
Characteristics: played by children -> gambling is an expectation, engaged in for fun -> professional sports is an expectation , involves competition -> solitaire is an expectation - inconsistency with an individual: category boundaries are fuzzy
e. g. if asked if an olive is a fruit people change their mind when asked more than one
Typicality
- members of category differ in term of how well they represent the category as a whole
e. g. sparrow is a typical bird chicken is atypical - affects categorization
- degree to which a particular object or situation or event is typical for its kind
graded membership
rating of all members are not equal
Typicality and Generalization
- People are more likely to take knowledge about typical example’s and apply it to atypical exemplars
Typicality and conditioned fear generalization
- typical mammals were paired with aversive shock during conditioned phase the fear response is generalized for atypical animals but further spread out less it applies
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 and likely doesn’t exist in the real world
- they should be easy tp categorize even if never seen
Posner’s prototype experiment
- created categories bases on 4 prototypes
- showed examples of these prototypes but not the actual prototype
- without prior experience they were able to categorize these prototypes
- even tho they never saw the prototype they were better at identifying them but old was identified faster this means theres a problem with this theory
Exemplar theory
- we don’t form a single example (prototype) its through a bunch of items
- created through as an average of what you’ve seen before
- individual exemplars are stored in memory
Family Resemblance
- no defining features but there are features that are common in the family
- ordinary categories may not have features that are shared by all but there are characteristics
- these features allow you to recognize a dog is a dog
production task
- ask people to name as many birds or dogs as they can. According to a prototype view, they’ll do this task by first locating their bird or dog prototype in memory and then asking themselves what resembles this prototype
So birds close to the prototype should be mentioned first; birds farther from the prototype, later on.
Whittlesea testing exemplar theory
- created prototypes (letter strings)
- created a list of exemplars either changing either 2 letter, 3 letter of 4 letters
- every exemplar had a matching exemplar that differed by 1 letter across the lists
- every word in list C there is a 2 letter difference in list A. List B is most similar to both
- a better transferring from list A to list B
prototypes
- less storage
- less to process when categorizing
Prototype vs exmplars Brooks study on skin disease
- expert dermatologists and inexperienced medical residents are shown labelled pictures of skin diseases and asked to judge how typical each one is of tat diagnostic category
- then asked to categorize new pictures that are unlabelled that were from the same diagnostic categories they were either similar or dissimilar from the original images
- experts do better on similar ones than dissimilar this suggests that experts are using exemplar theory they are remembering the original image
- residents don’t have a huge effect
- to some extent concepts are defined by exemplars
Theory based concepts
- prior knowledge influences how people categorize objects
how are concepts organnized
-hierarchical organization
- property inheritance
- lower level categories inherit higher level properties but not vice versa
(only goes in one direction)
- it takes longer depending on how far we have to travel in the network
e.g. can a canary sing this will be fast you don’t have to move a cross multiple networks
- the more modes you have to cross the longer it takes you
e.g. does a canary have skin
this takes longer becuase you have to cross more levels
levels of categorization
superordinate level (tool) -> Basic level (Hammer) -> Subordinate level (claw hammer)
Basic level of categorization
- objects are identifies faster if they are from the basic level
- its a level people spontaneously use
- first categories children learn
- balances the trade offs between informativeness and distinctiveness
- single word
exemplar based reasoning
- a new object resembles your grandpas chair and if grandpas object is a chair then its safe to say the new object is a chair too
- some categories rely on knowledge about specific category members
anomia
an inability to name common objects. But the specific loss depends on where exactly the brain damage has occurred.
propositions
defined as the smallest units of knowledge that can be either true or false
local representations.
Each node represents one idea so that when that node is activated, you’re thinking about that idea, and when you’re thinking about that idea, that node is activated.