Video Module 17: Concepts and Categories

Question 1

What are concepts and why do we use them to represent objects in our minds?

Answer 1

concepts are rich representations of things in the world
- concepts are interrelated to other concepts
- concepts help us form more general representations of objects; if we didn’t have them, we’d have to rely on only specific instances of things we encounter
- concepts assist our cognitive economy by allowing us to minimise processing effort and resources

Question 2

How do concepts increase cognitive processing efficiency?

Answer 2

Concepts help us with memory, reasoning, communication, creating complex or new concepts from pre-existing ones stored in our minds, and generalising objects to larger categories.

Question 3

What are key aspects of concepts?

Answer 3

1. typically stable
2. related to other concepts
3. typically a single word
4. help us understand the world

Question 4

How do concepts and categories differ?

Answer 4

Concepts are typically stable mental representations. Categories are ways of grouping items together on a basis of a certain criteria, and categories are not always stable.

Question 5

natural kinds

Answer 5

groupings or categories for items that occur naturally
- e.g. birds, trees, plants

Question 6

artifacts

Answer 6

groupings or categories for man-made items or ideas
- e.g. appliances, furniture, liberty, justice

Question 7

stable categories

Answer 7

those which people generally agree on what goes in them and what the criteria of inclusion are
- e.g. writing instruments, desserts, cats

Question 8

ad hoc categories

Answer 8

those which are unstable and defined for a specific purpose within a specific context
- e.g. “people sitting in the front row of PSYC 105”

Question 9

basic level of categorisation (features)

Answer 9

1. has its own word
2. not too general, not too specific
3. easy-to-explain commonalities between members
4. people’s initial or instinctive response to categorising items (e.g. “chair” vs. “swivel chair”)
5. tends to be used in speaking & reasoning about categories
6. children learn basic level categories first
7. not necessarily fixed; context and level of knowledge can alter what is a “basic level” category

Question 10

superordinate categories

Answer 10

those which include the basic level category along with other basic level categories; those which are above basic level categories
- e.g. “furniture” is a superordinate category for “chair”

Question 11

subordinate categories

Answer 11

those which fall under the basic level category; those which are included in the basic level category
- e.g. “corgi” is a subordinate category of “dog”

Question 12

How does categorisation help us make inferences about the world?

Answer 12

Categories help us make inductive and deductive inferences.
We can reach a general conclusion about members of a category based on specific examples of members in the category (inductive reasoning). We can also reach a specific conclusion about a given instance based on the general principles of the category to which that instance belongs (deductive reasoning).
- categorisation is an inductive inference because we infer which categories objects fall into based on their features

Question 13

What have researchers discovered in terms of the way that children make inferences based on categories?

Answer 13

A study by Gelman and Markman (1987) showed children a picture of a “bird” (flamingo) and a “bat,” telling them about the different ways they feed their babies. The researchers then asked children to make an inference about the way that a “bird” (a blackbird) feeds its babies.
- 85% of preschoolers in this condition guessed that the blackbird mashed up its food, like the flamingo
- The researchers found that children are sensitive to the labels that adults use for objects; they are easily able to learn new facts and extend them to other members of the same category

Question 14

classical theory of categorisation

Answer 14

The theory that a category is defined in terms of necessary and sufficient features.
- necessary features: those which an object must possess
- sufficient: enough to place an object in a category
- abstract representation of objects as lists of features; suggests that we do not store any information of specific exemplars
- all-or-none membership: sth is either a member of a category or not

Question 15

What are the criticisms of the classical theory of categorising objects?

Answer 15

1. for many categories, there aren’t distinct/defining features: often you can remove any particular feature of an object and still have it belong to a category (e.g. a dog with no tail is still a dog)
2. non-necessary features of objects can affect people’s categorisation choices: e.g. if a shape has all the requirements for a rectangle, people may still categorise it as a square if it has sides equal in length

Question 16

family resemblance (categorisation)

Answer 16

a method of categorisation in which there is no defining feature that members of a category must have, but there tends to be characteristic features that are common or typical amongst members of the category

Question 17

graded membership

Answer 17

the likelihood that an object belongs to a certain family/category
- the idea that items can be ‘better’ or ‘worse’ members of a category
- category membership is a matter of degree: a member is more likely to be part of a family if it has a greater number of typical features
- suggests that categorisation is probabilistic rather than deterministic: that having certain features probably makes an object a member
- categorisation is a matter of similarity; category boundaries are fuzzy

Question 18

typicality effects

Answer 18

in which people tend to see some members of a category as “more typical” than others
- some differences between members of a category are related to non-necessary features

Question 19

How can we assess typicality effects?

Answer 19

1. rating tasks: ppl rate the “X-ness” of an object
2. production tasks: ppl produce/write down as many category members as they can think of in an allotted amount of time
3. sentence verification tasks: ppl mark statements of objects as T or F
4. generalisation tasks: ppl decide if generalisations can apply to whole categories based on specific instances

Question 20

rating tasks (typicality effects)

Answer 20

in which ppl rate the “X-ness” of an object
- e.g. “How bird-like is this bird?”
- Researchers find that typicality ratings may be based on the total number of typical features a category member has
—this may explain common errors of categorisation, for example when people group dolphins with fish

Question 21

generalisation tasks
(typicality effects)

Answer 21

in which ppl decide if generalisations can apply to whole categories based on specific instances
- e.g. “If penguins can catch this disease, can all birds?”
- researchers find that features of a typical member are more likely to be believed as applicable to all category members than are features of an atypical member

Question 22

sentence verification tasks
(typicality effects)

Answer 22

in which ppl mark statements of objects as T or F
- 3 kinds of statements: true (typical), true (atypical), and false
- E.g. “Fish is meat.” (true, atypical)
- researchers measure response time and find that RT is faster for more typical examples

Question 23

production tasks
(typicality effects)

Answer 23

in which ppl produce/write down as many category members as they can think of in an allotted amount of time
- researchers measure order and frequency of examples listed amongst participants
- more typical examples are produced/recalled first and more frequently

Question 24

What are challenges to the classical theory of categorisation?

Answer 24

1. It’s nearly impossible to give adequate definitions of objects in a category
2. You can remove particular features of objects can still have them belong to a category
3. Typicality effects: people’s judgements of category membership reflect graded membership