Concepts

Concepts and Conceptual Structure L.P. Alampay Cognitive Psychology

Our concepts reflect how we divide the world into classes or categories. To categorize is to treat two or more distinct entities as the SAME or EQUIVALENT. The world can be partitioned in a limitless variety of ways, yet people find only a miniscule subset of possible classifications to be

Functions of Concepts 1. Cognitive economy By partitioning the world into categories, we decrease the amount of information we must perceive, learn, remember, communicate, and reason about

Functions of Concepts Enable us to infer beyond the given information Can infer non-perceptible attributes about an object (even if unfamiliar) once we are able to classify it Provide us with expectations to guide our behaviors

QuickTimeª and a TIFF (Uncompressed) decompressor are needed to see this picture.

Functions of Concepts 1. Can be combined to form more complex concepts and thoughts Our understanding of complex ideas hinges on understanding of constituent concepts Ang buhay ko ay parang telenovela. A dog is man’s best friend.

The structure & content of conceptual knowledge WHAT is being represented?

Theories of concepts should explain the coherence of categories, and why some categories seem natural (or privileged) and others are not. the class of things that weigh less than a ton and do not have stripes… the class of things that have feathers and can fly…

View 1: Feature-based or Similarity-based views

Our conceptual knowledge consists of the properties, features, or attributes of the instances of the concept or the members of the category We put things together because they are SIMILAR.

Feature-based views: Classical Concepts are defined by sets of individually necessary and collectively sufficient features. - Means that every instance of the concept must possess ALL features - And that objects that have all those features MUST be classified as instances of that

Feature-based views: Classical Bachelor = male + adult + unmarried QuickTimeª and a TIFF (Uncompressed) decompressor are needed to see this picture.

Triangle = closed form + three sides + interior angles sum

Feature-based views: Classical What are the defining features of the following concepts? Cup Chair Vegetable

Problems with the Classical View Failure to specify defining properties

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There seems to be no necessary and sufficient features to define most everyday concepts

Unclear cases regarding category membership

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Disagreement over whether objects are instances of certain categories Am I friend or lover ???

Problems with the Classical View 3. Typicality effects

- People can think about objects in terms of being more “typical” or better/worse instances of a concept - Measured by speed of categorization, latency of memory retrieval, recognition tasks - e.g., Malt & Smith, 1984

Feature-based views: Probabilistic Concepts are organized around a set of features that are only characteristic or typical among category members. - Category membership is thus fuzzy or ill-defined

Feature-based views: Probabilistic Family Resemblance principle The more typical instances of a category are those that share more features with other members of the category

Feature-based views: Probabilistic Concept represented as Prototype

An abstracted, MOST TYPICAL instance that possesses the most characteristic features

Concept represented as Exemplars

BUT! Typicality effects do not rule out classical views of conceptual structure.

Typicality effects were demonstrated EVEN IF subjects were able to state the defining properties of concepts (Armstrong, Gleitman, & Gleitman, 1983) odd number even number

Feature-based views: Dual-code Representation?

We code for two representations of a concept: A prototype (i.e. most typical) -

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May be used for “quick and dirty” identification purposes

A core consisting of properties that are necessary for determining category membership

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Defines boundaries, used for reasoning and making important judgements

Feature-based views: Dual-code Representation? Landau, 1984: Will the real grandmother please stand up? - Adults use core definition to pick out the grandmother - Children use the prototypical definition to identify the grandmother

Feature-based views: Dual-code Representation? Keil & Batterman (1984)

A smelly, mean old man with a gun in his pocket who came to your house and takes your TV because your parents didn’t want it anymore and told him he could have it. A very friendly, cheerful woman who gave you a hug, but then disconnected your toilet bowl and took it away without permission and no intention to

Problems with Probabilistic Views Feature similarity does not explain categorization.

• What counts as a feature? (Without constraints, any two things can be arbitrarily similar or dissimilar!) • What features are “essential”, “weighted”? (The importance or

Problems with Probabilistic Views Feature similarity does not explain categorization (continued)

• Goal-derived categories are not based on similarity to a prototype/exemplar • Thus, need to specify the principles that determine WHAT are to count as relevant features!

Problems with Probabilistic Views 2. The sum of the features is not the whole concept.

- Concepts are not simply a sum of independent features… - …rather, the structure of the concept is held together by the features PLUS the (functional, causal) relations binding the features together

Features of a car Has wheels Has an engine Has four doors Runs on fuel Has a roof “Today I saw a car with orange wheels.” “Today I saw a car with square wheels.”

“Today I saw a car with orange wheels.”  The owner is a hippie  The rest of the car is brightly painted  Car functions normally

“Today I saw a car with square wheels”  It cannot move  It was not intended to function normally  It may be a sculpture intended to elicit

View 2: Knowledge or Theory-based views Our knowledge of concepts and categories consist of the features or attributes of the instances of the concept/members of the category… PLUS …the underlying explanatory principles that determine the relevant features, their

View 2: Knowledge or Theory-based views 1. Explanations or theories provide the “cognitive glue” that binds features together in some meaningful relationship. Context Goals Higher-order knowledge memories

Cell phone Keys Wallet Laptop

Lion Tiger Cat Penguin Parrot Chicken

View 2: Knowledge or Theory-based views 2. Our knowledge/theories dictate which features are central and explains why instances of a category tend to go together.

straight bananas vs straight boomerangs soft knives vs soft diamonds polka-dot fire hydrants vs polka-dot yield sign orange wheels vs square wheels Psychological Essentialism (or the Essentialist Heuristic): People act as if things have “essences” that make them the thing they

View 2: Knowledge or Theory-based views 3. Our knowledge/theories provide the link between features of a concept and the “core” or “essence” of the concept - human perceptual system is biased towards discerning the features of objects that are likely to lead to the core of the objects