problem 4 - semantic memory

Question 1

what is a category?

Answer 1

A set of objects that can be treated as equivalent in some way

Most categories share more than just 1 property
- (eg. you know things about a Toyota car even if you only know other car brands, bc different cars have similar characteristics)

Question 2

what is a concept?

Answer 2

Mental representation we form of categories

• Assume that ppl’s concepts correspond more or less closely to the actual category
• Allow us to be able to know what to do in new situations & when confronting new objects even if you’ve never experienced it before
• Allow you to extend what you have learned about a limited number of objects to a potentially infinite set of entities

Question 3

nature of categories

Answer 3

Traditionally assumed that categories are well-defined = you can give a definition that specifies what is in & out of the category
- Provides the necessary features for category membership
- Those features must be jointly sufficient for membership

However, it has not been possible to find definitions for many familiar categories bcuz the world is messy & unclear

Question 4

what are borderline category members?

Answer 4

not clearly in or clearly out of the category - deals with the fact that for categories there are no clear boundaries

Question 5

what are fuzzy categories?

Answer 5

Have unclear boundaries that can shift over time

Question 6

what is typicality (categories)

Answer 6

Even among items that clearly are in a category, some seem to be ‘better’ members than others

Ranging from the most typical (the prototype) to borderline members (not clearly in or out)
- items that are less & less similar to the prototype become less & less typical

Question 7

sources of typicality (categories)

Answer 7

1. The frequency with which we encounter the object
   - Does have some effect, but is not the most imp variable
2. Family resemblance theory = items are likely to be typical if they:
   - Have the features that are frequent in the category
   - Do not have features frequent in other categories

Question 8

what are category hierarchies?

Answer 8

More concrete categories are nested inside large, abstract categories
- Basic level of categorization

Question 9

basic level of categorization

Answer 9

The neutral, preferred category for a given object, at an intermediate level of specificity
- Depends on people’s knowledge & interest in the category

Basic level categories are more differentiated: the category members are similar to one another, but they’re different from members of other categories

Question 10

goldilocks effect (categories)

Answer 10

Category used for something not too small (eg. brown bear) and not too large (eg. animals) but just right (eg. bear)

Question 11

what is psychological essentialism?

Answer 11

People ​​tend to believe that some categories have an underlying property that is found only in that category & that causes its other features

Question 12

what is essence (categories)

Answer 12

The intrinsic nature or indispensable quality of something, especially something abstract, which determines its character

Many categories don’t actually have essences

Question 13

signs of essentialism

Answer 13

• Objects are believed to be either in or out of the category (no in-between)
• Resistance to change of category membership or of properties connected to the essence
• For living things, the essences is passed on to offspring

Question 14

category verification task

Answer 14

Used to determine how we access categorical knowledge
- Asked to verify deny simple statements (e.g. a penguin is a bird or a robin is a bird) as quickly as possible
- Speed is the most imp variable in these tasks - fact that p’s verify that a robin is a bird more quickly than a penguin = tells us smth about how knowledge is organized

Question 15

feature verification task

Answer 15

Used to assess how the features of categories are stored & accessed
- Asked to verify or deny sentences like ‘a cat has pointy ears’ or ‘a cat has skin’
- Fact that p’s verify that cats have pointy ears faster than having skin = tells us smth about the proximity of these features to the concept ‘cat’

Question 16

what are semantic networks

Answer 16

Knowledge is stored in the form of associative networks in which concepts are represented by nearby nodes that correspond to related concepts or features of a given concept
- Related to but not based on brain structure
- Nodes in semantic network models: correspond to specific concepts & the link between them correspond to relationships among concepts

Question 17

what is the spreading activation model

Answer 17

Makes a number of assumptions about the representation of knowledge + central assumption that concept nodes are linked in an associative network

Links that connect concepts represent a variety of relationships:
- Category membership (canary → bird)
- Property to concept relationships (yellow → canary)
- More subtle relationships (canary → cat)

Question 18

what is the process of activation according to the spreading activation model?

Answer 18

A given concept is presented → corresponding node is activated → activation spreads out to other concepts in the network

• Strength of activation decreases w time, distance & the number of concepts activated (more concepts activated = the less activation)
• The activation that reaches any concept node is summed up & if the activation passes a threshold value, that concept will be activated

Question 19

what is semantic priming?

Answer 19

Semantic priming = the tendency for the processing of 1 stimulus to enhance or speed up the processing of a related stimulus
- eg. yellow primes for sun, canary & lemon
- Yellow give head start towards the threshold

Question 20

what are natural categories?

Answer 20

Those that occur naturally in the world - essentially define themselves
- Members share important features
- E.g. flowers, animals, trees

Question 21

what are artifact categories?

Answer 21

Objects or conventions designed or invented by humans to serve particular functions
- Members don’t seem to share the same type of basic features
- E.g. tools, sports, furniture

Question 22

what are ad hoc categories?

Answer 22

Formed in the service of some goal
- Members cohere only bcuz of their relation to the context at hand
- Share very little similarities or none at all
- E.g. things that ppl take on holiday

Question 23

what are metaphorical concept?

Answer 23

• abstract concepts, don’t have a lot in common
• can be completely different in what they are but a common theme unites them - eg. dead-end job, abusive relationship, moral dilemma

Question 24

what is similarity-based categorization?

Answer 24

Asserts that categorization is a matter of judging the similarity between the target object & some standard in LTM
- Either a clearly specified set of features: classical view

Question 25

what is the classical view of concepts?

Answer 25

Items are classified into particular categories if they have certain features/characteristics - categories are traditionally assumed to be well-defined = either IN or OUT - Features are both necessary & sufficient for defining the concept - Categorization is based on whether the set of features that characterise a given item is similar to the features that define the concept = similarity based view

Question 26

criticisms of the classical view of concepts

Answer 26

Many concepts are difficult to specify in terms of necessary & sufficient features - due to the rigidity of category boundaries Doesn't account for the typicality effect (graded structure of items) → cannot explain why chair comes up more often when we think of a furniture than a carpet (MOST IMPORTANT criticism) Doesn't take into account fuzziness / borderline members & ignores psychological essentialism

Question 27

what is the prototype theory of concepts?

Answer 27

People have a summary representation of the category → a mental description that is meant to apply to the category as a whole - Features are weighted by their frequency in the category - When you try to classify an item - you see how well it matches that weighted list of features Typical category members have more higher-weighted features = easier to match them to ur conceptual representation - Less typical = fewer/lower weighted features = don't match representation as well

Question 28

criticisms of the prototype theory of concepts

Answer 28

The simple average of people’s representations of concepts does not capture the complexity & sophistication - we have sensitivity for how certain features within categories go and don’t go together Prototype is not context-sensitive Can't explain conjunction (co-occurrence) of concepts

Question 29

what is the exemplar theory of concepts?

Answer 29

Denies that there is a summary representation: instead, claims that ur concept of an item is remembered examples of that item you have seen See an object --> compare it to the exemplars in your memory & judge how similar it is to exemplars in diff categories - These similarity scores are added up for each category, compared & the category w the highest score is chosen

Question 30

criticisms of the exemplar theory of concepts

Answer 30

In some circumstances people are truly using abstracted summary representations - one that’s constructed from repeated encounters Surely not every single interaction with every single item is stored in memory, and if not - how is determined with ones are & which ones are not Method: same items shown over and over again, lab is unlike the real world

Question 31

current combined view of concepts

Answer 31

Concepts are represented through multiple cognitive systems: - General descriptions (eg. dogs have 4 legs) - Memories of exemplars: your grandmas dog - Some categories involve rules (eg. all babies have a rooting reflex) - General knowledge (eg. dogs have a brain)

Question 32

what is semantic memory?

Answer 32

knowledge about objects, facts & concepts + words & their meanings

Question 33

what is semantic dementia?

Answer 33

Associated with temporal lobe atrophy → impairment of conceptual knowledge - Progressive deterioration of conceptual knowledge that supports semantic performance, independent of modality - Research on patients with this condition suggests that conceptual knowledge is supported by a central system

Question 34

Bozeat et al (semantic dementia article) - method

Answer 34

8 control p’s + 6 p’s w temporal lobe atrophy - P’s asked to draw items from a list - Drawings from patients compared to controls for amount of features they contained - Patients had to take other tests to assess cognition & skills - After tests, patients had to make drawings of 64 objects with unlimited time

Question 35

Bozeat et al (semantic dementia article) - results

Answer 35

- Patients drew a lot less target features than the controls = damaged conceptual knowledge - Sig correlations in perf between drawing assessment, object naming & word-picture matching → all these tasks require conceptual knowledge: there’s selective damage to central conceptual knowledge - Familiarity of an item led to better success in drawing

Question 36

Bozeat et al (semantic dementia article) - conclusion

Answer 36

- P’s w semantic dementia produced sig less info & features than the control group = there is damage to central conceptual knowledge - When a patient knew an object well, they usually knew how to draw more features of this object. - The features that frequently appeared in a category were often drawn