Knowledge and Concepts

What is special about basic level categories (consider learning and speed of processing)?

Learned first, faster categorization and naming. Have the ideal mix of shared and distinct features

ex. “Car” is informative b/c distinguishable from truck but gives no unnecessary detail.

Are basic level category effects the same as typicality effects?

No, they resemble the typicality effects but are not the same. For both the basic level category effect and typicality effect they are easier for people to remember. (Rosch:) In the case of the basic level category, it provides something that is not too vague but not too detailed, which makes identification and recognition easier. For the typicality effects, it is the most common and typical examples, which makes it easier for people to recognize.

Explain spreading activation within the conceptual network.

In spreading activation, concepts are nodes in a network connected by relations. Activating one concept makes activation spread across connections to related concepts.

Line length = strength of association. Shorter line = stronger connection.

What are the “nodes” and “connections” in spreading activation models?

The nodes are concepts.

The connections are the relations between the concepts.

What kinds of connections might exist in the stored network approach?

Connections can be based on category, association, functional, feature, or part-whole.

Can connections vary in strength in the stored network approach? If so, why?

Yes, connections can vary in strength. This is b/c of the typicality effects.

Ex. flower → rose is a stronger and therefore shorter link than flower → tulip. Rose is judged more typical and accessed faster.

Explain the classical theory of concepts.

• What's in the mental representation?

• How is category membership determined?

• Can the classical theory explain why typicality effects occur in experiments?

• What kinds of categories might the classical theory provide a good framework for?

In the classical theory of concepts, concepts are definitions made of defining features that are singly necessary (each is required) and jointly sufficient (together they are enough).

Ex. bachelor = unmarried + male + adult

The theory works well to provide a good framework for clearly defined categories with strict rules or defining features → ex. geometric shapes.

The theory cannot explain why the typicality effects happen in experiments. The classical theory assumes category members are equally representative, but typicality effects show that some members are more representative than others.

What is a prototype? Do prototypes for natural kinds really exist in nature?

• How does the prototype theory differ from the classical theory.

A prototype is a mental representation of the major, most common, most important features of a category.

Prototypes are mental representations created by our minds, not necessarily real, perfect examples that exist in nature; they can therefore not exist naturally in nature.

The prototype theory differs from the classical theory since more typical member shave higher resemblance and sit closer (within a mental distance). In the classical theory every member meets the definition equally.

Discuss the exemplar theory as an alternative to the prototype theory.

• According to this theory, what are our concepts made up of?

• How does the exemplar theory explain typicality effects?

• Does the exemplar theory have as much empirical support as the prototype theory does?

In the exemplar theory concepts are the storage of many individual examples. It explains the typicality effects since exposure to one exemplar counts for more; that means more “typical” examples will count for more due to being exposed to it more.

Compared to the prototype theory, there is a collection of specific cases rather than one abstracted summary.

Discuss the knowledge-based theory.

• Like the prototype theory, the knowledge-based theory suggests that our concepts contain features. What differentiates this from the prototype theory?

• Explain Ahn et al.'s research demonstrating that the feature at the beginning of a causal chain is important in determining category membership.

In the knowledge-based theory concepts contain causal relations between features; we categorize partly by reasoning about cause and effect. Meanwhile, in the prototype theory, concepts are mental representations of key features that are the most important and common rather than cause and effect. With the knowledge-based theory we rely on the outside knowledge we know to categorize concepts.

Roobans (Ahn et al):

Participants told the animal rooban: (X) eats fruit, (Y) has sticky feet, (Z) buils nests in trees. Told of causal and effect chain X → Y → Z

When told animals that have a changed X statement, least likely to categorize as a rooban → showcases causal reason for categorizing.

Explain the typicality effects

Typicality effects:

1. Robins are susceptible to disease A

2. Turkeys are susceptible to disease A

Conclusions: Therefore, all birds are susceptible to disease A.

Q: which bird is more typical? Robins since traits of more typical exemplars are more likely to be generalized to the population

Explain the diversity effects

1. Robins and Sparrows are susceptible to disease A

2. Cardinals and Turkeys are susceptible to disease A

Conclusions: Therefore, all birds are susceptible to disease A.

Traits of diverse sets for exemplars are more likely to be generalized to the population —> so #2 is judged stronger.

For two objects that are different, they span more of the category.

Explain the monotonicity effects

1. Hawks, sparrows, and eagles have sesamoid bones.

2. Sparrows and eagles have sesamoid bones.

Conclusion: Therefore, all birds have sesamoid bones.

More inclusive sets produce stronger arguments —> 1 is a stronger argument