Introduction to Categorization Theory (Goldstein Ch 9: Knowledge) Psychology 355: Cognitive Psychology Instructor: John Miyamoto 05/10/2018: Lecture 07-4 Note: This Powerpoint presentation may contain macros that I wrote to help me create the slides. The macros aren’t needed to view the slides. You can disable or delete the macros without any change to the presentation.

Lecture probably ends here Outline Finish: Eyewitness memory Introduction to categorization theory (Goldstein's chapter 9 is named "Knowledge) Categorization – what is it? How are objects placed into categories? The definitional theory of categorization Problems with the definitional theory of categorization Prototype theory of categorization Exemplar theory of categorization Lecture probably ends here Psych 355, Miyamoto, Spr '18 Line Ups Versus Show Ups

Lineups versus Show-Ups – What Are They? Classic showup: Police show only one person to a witness, often somebody who was caught near the scene of the crime. Question: "Is he the man you saw?" Classic lineup: Police show 7 people to the witness: Question: "Do you see the perpetrator in the line up?" Improved showup = sequential showup: Police tell the witness, "We're going to show you a series of men (of unstated length). Stop me when you see the perpetrator." Contrary to most people's expectations, show ups are more accurate than line ups. Why are showups more accurate than lineups? Psych 355, Miyamoto, Spr '18 Why Lineups & Showups Differ as Cognitive Tasks

Cognitive Differences Between Lineups and Showups Classic showup: Witness asks himself/herself: "Did I see this person do the crime?" Classic lineup: Witness assumes that the perpetrator is in the lineup. Witness asks himself/herself: "Which of these men looks the most like the person that I saw?" Sequential presentation = sequential showup (Goldstein refers to this a sequential presentation) With each person, the witness asks himself/herself: "Am I sure that this is the person who I saw do the crime?" Lindsey & Wells (1985) found that the sequential showup greatly reduced false id when the perpetrator was not present (43% vs 17%) Sequential showups slightly reduced the rate of true id when perpetrator is present. Mistake! Psych 355, Miyamoto, Spr '18 Recommendations for Improving Eyewitness Memory

Recommendations for Improving Eyewitness Memory Use a sequential showup (Goldstein would call it a sequential presentation). In a showup, use non-suspects who are similar to a suspect. Inform witness that the perpetrator may not be in a showup. Administrator of showup should not know who is the suspect. Get confidence rating immediately after the initial identification. Avoid giving feedback to the witness after the lineup Use cognitive interview techniques; do not prompt the witness with leading questions. See Wikipedia article on cognitive interview techniques: http://en.wikipedia.org/wiki/Cognitive_interview Cognitive interview technique includes: Have witness mentally reinstate the environment and personal context of the event. Have witness report in depth the details of the event, including details that may not seem important or relevant. Describe the event in several different temporal orders. Report the event from various perspectives, e.g., what could another witness see or hear? Psych 355, Miyamoto, Spr '18 Outline of Categorization Topic

End of the Memory Topic The slides that follow this slide pertain to Goldstein’s Chapter 9 (Knowledge; I refer to it as the categorization topic). Chapter 9 will not be on Midterm 2. Psych 355, Miyamoto, Spr '18

Outline of Categorization Topic Concepts, categorization, and knowledge Categorization – what is it? How are objects placed into categories? The definitional theory of categorization Problems with the definitional theory of categorization Prototype theory of categorization Exemplar theory of categorization Psych 355, Miyamoto, Spr '18 Categorization – Examples

Categorization – Examples Categorize objects in the physical world. E.g., tables, chairs, cars, dogs, cats, trees, water, etc. Categorize types of people. E.g., policemen, teachers, students, politician, etc. E.g., friend, enemy, helpful, inconsiderate, smart, talkative, etc. E.g., white, black, asian, ...., catholic, muslim, hindu, ...., Abstract categories. "___ is a crime", e.g., theft is a crime; complaining is not a crime. "___ is a relative of mine." (Kinship is an abstraction.) "credit" in the financial sense is an abstraction. Psych 355, Miyamoto, Spr '18 Inferences with Categorizations

Inferences with Categories Example of Reasoning with Categories Type of Inference I see a dog and say, "That's a mammal/dog/collie." Categorize an object (put it into a category) A friend tells me, "I have a collie," and I think to myself, "I hope she doesn't mind dog hair on her clothes." Draw an inference from a categorization to other properties of the object. A friend tells me that fluorescent light can wreck a cd that contains data. I think to myself, I wonder if the same thing is true of dvd's? Draw an inference from a property of one category to a possible property of another category. Psych 355, Miyamoto, Spr '18 Categories Imply a Lot of Other Information – Cat Example

Knowing the Category Provides a Lot of Information Psych 355, Miyamoto, Spr '18 Definition of Categorization

Categorization – What is it? Goldstein book: Categorization "is the process by which things are placed into groups called categories." This is an incomplete definition. Below is a better definition. The psychology of categorization has to do with: how we assign objects or events to categories; the structure of knowledge that we use to organize our knowledge of categories (category structure); the inferences that we draw when we learn that an object or event belongs to a category; how we learn new categories (Children learn new categories frequently; adults learn new categories from time to time) These are all examples of semantic knowledge. Psych 355, Miyamoto, Spr '18 Distinction Btwn Concepts & Categories

Categories and Concepts The word "concept" emphasizes knowledge of relationships between concepts. E.g., the concept of a cat includes knowledge of its biology, appearance, behavior, its relation to human life styles, etc. Example: mokita (Kivila language) is “truth we all know but agree not to talk about” (Wikipedia) Concept of "time" includes knowledge of all sorts of temporal relationships, e.g., relations of "before" and "after." Related relations and concepts s of "duration," "instant", "concurrency", "distant past," "recent past." The word "category" emphasizes the set of all things that are joined together under a common label. E.g., every cat is a member of the category "cat"; every dog and every cat is a member of the category "carnivore." Psych 355, Miyamoto, Spr '18 Relationship between Knowledge and Categories

Categorization and Knowledge Goldstein calls the chapter topic “Knowledge” – why? This is a hypothesis – not a fact. IMO: The structure of categories and the structure of concepts are related to the structure of knowledge, but none is identical to any of the others. ? Psych 355, Miyamoto, Spr '18 Definitional Approach to Category Membership

Definitional Approach to Category Membership Originated with Aristotle. According to the definitional approach, category membership is determined by checking a list of necessary and sufficient features. Example: Definition of a tea cup. Concrete object Concave Can hold liquids Has a handle Can be used to drink hot liquids Properties 4 and 5 are debatable. Chinese tea cups. Lacquer cups. If you omit 4 and 5, then there are many objects (bowls) that satisfy 1 - 3. Psych 355, Miyamoto, Spr '18 Problems with the Definitional Approach

What Do These "Chairs" All Have in Common? Maybe there is nothing that ALL chairs have in common, ..... but they all share a family resemblance. Psych 355, Miyamoto, Spr '18 Problems with the Definitional Approach to Categorization

Problems with the Definitional Approach How do we discover the definitions? For many categories, it is doubtful that necessary and sufficient features exist. Example: If we call someone "friendly," what are necessary and sufficient features for calling someone friendly? The definitional approach does not explain important aspects of human categorization. E.g., it does not explain typicality effects in categorization response time. See the Rosch color priming study to be described later. E.g., it does not explain typicality effects in semantic memory experiments (Goldstein calls this the "sentence verification technique"). Psych 355, Miyamoto, Spr '18 Prototype Theory of Categorization

Prototype Theory of Categorization Cognitive psychologists were dissatisfied with the definitional approach to representing cognitive categories. Eleanor Rosch: Categories are organized around a category prototype. Category prototype represents typical features of category members. Family resemblances. Next: Digression regarding family resemblances Psych 355, Miyamoto, Spr '18 Family Resemblance Idea - Background

Family Resemblance Idea - Background Composite A "family resemblance" photograph – popular in late 19th & early 20th century. Take multiple exposure photo of all family members. Only the common features are retained. The photo looks like everyone in the family, but is not any one person. Images downloaded from: http://slantoflight.org/?p=553 Psych 355, Miyamoto, Spr '18 Continuation of Present Slide with Composite Image

Family Resemblance Idea - Background Composite A "family resemblance" photograph – popular in late 19th & early 20th century. Take multiple exposure photo of all family members. Only the common features are retained. The photo looks like everyone in the family, but is not any one person. Ludwig Wittgenstein – early 20th century philosopher. Proposed that the structure of a concept is like a family resemblance photo. Images downloaded from: http://slantoflight.org/?p=553 Paul Wittgenstein Concert pianist Lost right arm in WW I Psych 355, Miyamoto, Spr '18 Family Resemblance in Concept Theory

Thursday, 10 May, 2018: The Lecture Ended Here Psych 355, Miyamoto, Spr '18

Family Resemblance & Concepts Famous example: Wittgenstein says that there are no necessary and sufficient conditions for something to be a "game", but there is a family resemblance among games. Playing checkers or bridge; playing football; skipping rope; children play acting as if, e.g., having a tea party; trash talking Similarly, there are no necessary & sufficient conditions for something to be a chair, but there is a family resemblance among chairs. Psych 355, Miyamoto, Spr '18 Return to Slide Showing the Prototype Theory of Categorization

Prototype Theory of Categorization Eleanor Rosch proposed: cognitive representations of categories are like family resemblances. categories have prototypes – category structure is created by the relationship between category members and the category prototype. Prototypes (mental representation of a concept) are like family resemblance photographs – they retain the typical characteristics of many particular examples. Psych 355, Miyamoto, Spr '18 Examples of Birds & the Prototypical Bird Image