language-concepts and meanings

Question 1

lecture 4 learning objectives

Answer 1

• Understand prototype, exemplar and theories approaches to concepts
• Be able to describe converging sources of evidence showing typicality effects
• Be able to describe potential problems with prototype and exemplar models
• Be able to describe evidence for a “concepts as theories” approach
  -Understand how prototype, exemplar and theories approaches might combine

Question 2

what are concepts

Answer 2

-mental representations of categories
-all words have an underlying concept
-not all concepts are labelled by a word eg ‘brown dog’
-

Question 3

one way we conceptualise
dictionary definition approach
-dog

Answer 3

a dog is a creature that is
-mammalian
-has 4 legs
-barks
-wags its tail
this doesn’t fit well with the way people behave when we ask them to reason about concepts and categories
-when we get people in the lab nd aks them to think about concepts and categories they don’t behave as if this is the way they organise their information

Question 4

dictionary definition approach problem

Answer 4

Ludwig Wittgenstein (1953)
-‘philosophers have tried for thousands of years to define terms such as ‘virtue’ and ‘knowledge’
-and there is always exceptions eg defining game
-an activity most often practiced by children
-engaged in for fun
-has certain rules
-involves multiple people
-is in some ways competitive
-is played during periods of leisure
-its difficult to create a definition for any given concept, always exceptions that don’t meet the rule

eg poker cant be played by children, games dont always involve multiple people, c

Question 5

explain family resemblance in words
how does this look in psychology?

Answer 5

-Wittgenstein proposed that members of a category have a family resemblance to each other
-each category has ‘characteristic features’
-these are features that most category members have
-the more features an object has, the more likely it is to be in the category

how does this look in psychology
-prototype theory (Eleanor Rosch and colleagues , mid 1970s onwards)

Question 6

what is prototype theory

Answer 6

prototype theory (eleanor Rosch and colleagues, mid 1970s onwards)
-when we think about categories, we have a prototype of that category and that’s how we make decisions about members of that category by reference to this prototype
-a prototype = the ‘average’ member of a category

Question 7

prototypes in practice

Answer 7

-simple category like birds, your prototype bird is going to be your average of all the birds you’ve ever encountered.
-when you encounter a new object and trying to decide whether or not thats a bird, you can compare it to your prototype and if its close enough you can categorise it as a bird

Question 8

implications of prototypes
-fuzzyboundaries
-graded membership

Answer 8

fuzzy boundaries - no strict dividing line between different concepts,
-you just have prototypes and things can be closer or further away from these individual prototypes , but there’s no point at which you can see if something is definitely part of a category

graded membership- (not all category members are equal)some members of the category are going to be better members of that category in that they’re closer to the prototype

Question 9

prototype theory- evidence
sentence verification task

Answer 9

-consistent in labs when you get people to reason about categories
-you get participants in the lab and present them with sentences
,pressing one button if their true and button if its false
-you measure their reaction time (how quickly can they make these descion)
-eg sentences robin is a bird, penguin is a bird, camel is a bird
-interested if their faster to respond to robin then penguin
-they are faster in responding to robin, because robin is closer to the prototype of that category

What is an example of the Typicality effect?
For example, a robin is more often judged to be a typical member of the category bird than is a chicken.

Question 10

prototype theory evidence
production tasks

Answer 10

eg list 5 vegetables
-people tend to be quite consistent in what they do in these tasks
-items closest to the prototype are likely to be named earliest
-the assumption is that their memory search starts with the prototype and works outwards
eg prototype veg is carrot and prototype fruit is apple

Question 11

prototype theory evidence
picture identification

Answer 11

-participants see a series of pictures and press ‘yes’ if its a dog and ‘no’ if its not
-aa with sentence verification, responses to certain dogs are faster than others
-eg faster to say border collie is a dog than chihuahua

Question 12

prototype theory evidence
rosch 1975 typicality studies

Answer 12

rosch
‘we all know that some birds are ‘birdier’ than others , some dogs are ‘doggier’ than others, and so on. I’m going to present you with a list of birds and dogs, and i want you to rate each one on the basis of how ‘birdy’ or ‘doggy’ it is’

-items farther from the prototype are rated as less ‘birdy’ / ‘doggy’

-people reason explicity as if they have a sense of what the prototype is.

Question 13

prototype theory - evidence
-tasks that involve thinking bout categories

Answer 13

participants asked to make up sentences about a category eg birds
tendency to respond like
-;i saw two birds in a tree’
‘i like to feed the birds in the park’ but not something like ‘the bird was resting on an iceberg’

experimenter rewrites the sentence, substituting the name with a specific member of the category
‘i saw two robins in a tree’
‘i like to feed penguins in a park’

-then ask a new group of participants to rate the new sentences for silliness/implausibility
-people seem to think about the prototype when they generate the sentences, once you replace it with another example that isnt a prototype it does work
-this is all typicality effect(there are typical responses)

Question 14

problems for prototype theory

Answer 14

-concepts can be very complex
-works well with dogs, birds and animals ,colours but not certain concepts

Australian aboriginal language of Dyirbal (Lakoff,1987)
-a book called ‘Balan’ - women, fire, and dangerous things- its called this because there’s a language called Dyirbal and has this categories for things, that are really important because they tell you how to use those words within a sentence
- so if a word falls into a certain category, you have the adjust the rest of the sentence to fit that
-this isn’t unusual in language eg French has dramatical gender which can change the sentence
- Balan is a category that primarily includes women fire and dangerous things ‘but it also includes birds that are not dangerous as well as exceptional animals, such as the platypus,bandicoot and echidna,’ p5

peoples prototypes seem to change with context
-eg European animals verses African animals
-if they had a prototype animal it shouldnt matter what the context is, but it does so suggests categories are not as simplistic

Question 15

exemplar theory/ instance theory

Answer 15

-exampler theory says when we are reasoning about categories what we do is we loo k at our cumulative experience of individual instances of that category and we compare new objects against that

-if your asked to make decsion a piece of furniture eg is this a chair, apparently you compare the chair to your prototype of chairs
-another way we might do this is go through our memory of all the chairs weve encountered and if the object matches one of those then we say yes- this is an example of examplar theory

Question 16

exemplar theory vs prototype theory
-definitions

Answer 16

exemplar based reasoning
-we categorise objects by comparing them to examples of a category in memory

prototype theory
- we categorise objects by comparing them to a mentally represented ‘standard’

Question 17

exemplar theory and typicality effects

Answer 17

exemplar theory is fine with typicality effects

-‘a robin is a bird’
-our memory search will be very fast- robins are often encountered

-‘a penguin is a bird’
-our memory search will be somewhat slower-penguins are a less common occurrence

Question 18

exemplar theory
-why people preserve information about variability within a category when the perform tasks
rips and collins (1993)

Answer 18

rips and collins (1993)- people seem to be sensitive to the nature of the category

study done in the 90s-wanted to know whether people were sensitive to the nature of a category when they performed a task
-they gave the example of a pizza and a ruler
-average pizza and ruler back then were both 12 inches long (but pizzas are much more variable than rulers, you get all different sizes of pizzas)
-they were interested if people reason differently due to this (in prototype theory this should not matter)
-asked participants whether a new 19” object was likely to be a pizza or a ruler
-prototype theory says you should get an even 50-50 split of responses
-but participants usually say ‘pizza’
exemplar theory preserve information about this kind of variability

Question 19

prototype vs exemplar
which one is better?

Answer 19

-likely we reason using both

consistent with exemplars
-people seem to be able to adjust their categories
-eg if asked to make judgements about European versus African animals
-consistent with exemplars - we bring different exemplars to mind in different situations

-exemplar theories overall seem to provide a slightly better account of peoples performance
-but prototypes are a good quick measure,

Question 20

prototypes and exemplars-developmental perspective
what happens when a child first encounters eg a dog

Answer 20

eg kids can figure out dogs (even from weird cartoons) and know whats a dog and whats not regardless if its hard to tell and regardless of the variability in dogs

-whats likely going on is that when they initially encounter these objects they probably use exemplar based reasoning
-so when they first learn what a dog is they have one example to go off of and the first few times all the can do is add new members to the category as they encounter more dogs
-but the more they see them they start to develop a prototype for the category so they start to average them together
-movement from exemplar to prototype reasoning seems plausible

-this is consistent with adults in labs

Question 21

problems with typicality
keil(1986) study

Answer 21

keil (1986) study with children as participants
-they asked children to reason about different categories -ask them things like could you turn a toaster into a coffee pot
-kids often acknowledged this would be possible

then they would be asked could you turn a skunk into a racoon?
-they understood you could paint and teach a skunk to be like a racoon
-but they wouldn’t accept that it would be a racoon
-resistant to the idea a species could change

-argued that children have theories about how world works
-info like something that’s mechanical you can change its function
-but animals you cant change their species

Question 22

problems with typicality
sea lampreys versus whales (McCloskey and glucksberg 1978)

Answer 22

-particpiants judge whales to be more typical of the concept ‘fish’ than sea lampreys
-but they still respond that sea lampreys are fish and whales are not
-people have an awareness of typicality but that’s not how they reason about these animals.
-suggests they have an additional layer of information that they use

Question 23

prototype and exemplars account for much of how we reason about concepts…but..

Answer 23

but other beliefs and knowledge must also contribute to our reasoning about categories

Question 24

concept as theories
murphy and medin 1985
clean vs unclean animals bible
-what makes these categories sensible?

Answer 24

-idea that concepts are a theory about the way a wordl works
example they used etc
-clean versus unclean animals in the bible
-clean animals include gazelles,frogs,most fish,grasshoppers, and some locusts
-unclean animals include camels,ostriches,crocodiles,mice,sharks, and eels

what makes these categories sensible or coherent?
a theory or explanatory framework
-theory that governs if its clean or unclean relating to :
-relating to habitat,biological structure and form of locomation

Question 25

concepts as theories-developmental perspective

Answer 25

-children evolve theories about categories through childhood
eg for a racoon, will include a set of beliefs such as
-they are biological creatures
-they are wild animals

see lampreys versus whale
-our ‘theories’ about whales outweigh their fish typicality

racoon/skunk versus kettle/toaster
-our ‘theories’ about the racoon outweigh its outwards appearance

Question 26

concepts as theories evidence
lion/gazelle question

Answer 26

(a) a lions blood contains a certain enzyme. will a gazelles blood contain the same enzyme
(b) a gazelles blood contains a certain enzyme. Will a lions blood contain the same enzyme

people are more likely to say yes to b than a
-this relates to our knowledge about the food chain (lions eat gazelles so it would make sense they contain the same enzyme)
gazelles dont eat lions

-our theories about how the world works seem to predict how participants perform that task

Question 27

concepts as theories evidence
role of typicality

Answer 27

-there seems to be a role for typicality too
(a) robins are vulnerable to a new disease. will ducks be vulnerable too? versus
(b) ducks are vulnerable to a new disease. will robins be vulnerable too
people more likely to say yes to a than b

-if you give someone a typical case they’re more likely to assume what happens to a typical case will apply to a non typical case
- we seem to make inferences from typical to non typical cases more than from non typical to typical cases
ducks are less typical so we assume it wont apply to a typical member, but robins are typical so we think that itll apply to ducks (non typical)

Question 28

concepts as theories
limitations

Answer 28

-theories so far don’t really account for our ability to understand novel combinations of concepts
-how do we know what a tree penguin is ? if we are asked this we will be quite consistent in how we respond to that
-quite good at reasoning about things we’ve never encountered before

we are good at using figurative language (non literal language)
-weve focussed on literal language here
-how do we understand phases like ‘some jobs are jails’ or ‘bob was an oxygen theif’
-we use metaphors etc that aren’t literal
humans are really good at reasoning

Question 29

where does this leave us
summary of theories and their use

Answer 29

-prototypes and exemplars are good heuristics (like rules of thumb) for judging category membership
-fast and usually accurate

exemplars allow finer grained reasoning; we can work with new categories or fine tune old categories for the situation

but we have an additional set of beliefs about each concept we hold
-useful for complex reasoning

as we learn categories it may be that exemplars become prototypes and that we develop theories about our prototypes