6 - Categories and Concepts (w/o textbook)

2 cognitive mechanisms

1. attention

2. memory

attention

• allows you to focus finite mental resources on key parts of the active scene

memory

• recalls specific behaviours + thoughts appropriate to current needs

categorization is ______ and often _______

constant, intuitive

3 basic functions of categorization

1. classification

2. understanding

3. communication

classification

• the ability to classify objects that LOOK different in the same group

  • e.g. if you see these apples, they look different (cause of their colours) but you know they are all apples

understanding

• ability to evaluate a situation and act appropriately based on prior experiences

  • e.g. you see 2 people shouting and decide it is a private conflict that you shouldn’t intervene in

communication

• ability to describe complex ideas/objects using a single label

  • e.g. furniture, cat, sport, classroom

illusion of the expert

• the feeling that a task is easy for everyone because its easy for YOU

  • e.g. tying a shoe is ez for you, but not for a child

do simple or complex categories leave us more susceptible to the illusion of the expert?

simple (because we find categorization so easy in our heads, but trying to actually teach a computer rules to categorize something is extremely difficult)

true or false: humans have an internal representation of categories that is independent of the explicit rules that we use to try to define membership

true

prototype theory

• we categorize objects by comparing them to an internal “best” representation of a given category (called a ‘prototype’)

  • e.g. you see a new plant and wonder if its a tree; you compare it to your prototype of a tree - the further away the new plant is from your prototype, the less likely it is to be categorized as a tree

prototype

average of a category

• e.g. if you try to picture a fruit, each person will think of a different fruit that relies on their internal category representation

prototypes are formed through _________

experience

e.g. if you live in a tropical environment, your prototype of birds would probably look like some sort of tropical bird, whereas if you live in ontario, your prototype would probably be a robin

a prototype does/does not need to exist in the real world to serve as an internal representation for a categorization

does not

evidence that supports prototype theory

• when asked "is a robin a bird” respondents answered quickly

• when asked “is a penguin a bird” respondents answered slower

  • suggests that category members that are closer to the prototype are categorized quicker and easier

evidence against prototype theory

• if you are asked to identify prototypes for 6 categories, and asked the same thing a week later, you will probably come up with different prototypes; your internal representation has changed

why should (but they don’t) prototypes remain stable over time?

• the more prior cases of a category you’ve experienced, the less likely 1 new case will shift your prototype

exemplar theory

• we categorize objects by comparing them to every previously stored experience (exemplar) in a given category

  • you ‘search’ through your exemplars to find one that is similar enough to the object/experience you are currently facing, then identify it as a member of the same category

exemplar

• each previously stored experience that you compare new experiences to in order to categorize them (exemplar theory)

how does exemplar theory explain the robin-penguin example

• you’ve had many more exemplars of robins than penguins (if you live in north america) in your memory

• therefore, you can retrieve a robin exemplar much more quickly

evidence supporting exemplar theory

• doctors were asked to identify skin diseases twice, 2 weeks apart

• some of the diseases were repeated in the 2nd trial

• doctors were 20% more accurate

  • suggests that adding even 1 more exemplar increased their ability to categorize the disease; in favour of exemplar theory

summary chart of prototype vs exemplar theory

is prototype theory or exemplar theory more backed currently?

exemplar theory

children as young as _ are able to understand general categories

3

can children understand hypothetical categorization?

yes

can children understand the innate properties of a category?

yes

• you can change the nature of a machine, but not any living thing

baboon object categorization example

• could be taught to classify b/w food and non-food items

• could also be taught to classify b/w the same category (e.g. 2 food items or 2 non-food items) and the different category (e.g. 1 food and 1 non-food item)

• 90% accuracy

true or false: animals can categorize just as well as humans do

false: they have limitations (which may be why they don’t have language)

categorization explains the social phenomenon of ____________

stereotyping

concepts

a mental representation of a category (similar to a prototype?)

classical view of categories

• for every category, there is a set of rules that defines it (this is rarely the case)

CAPTCHAs

• tell humans apart from computers, bc humans are great at categorization, while computers are not

  • asks “select all images with a ____”

CAPTCHAs follow which theory of categorization?

exemplar theory