Ebook Cognitive psychology (6th edition): Part 2

7 C H A P T E R TheLandscapeofMemory:Mental Images,Maps,andPropositions CHAPTER OUTLINE Mental Representation of Knowledge Communicating Knowledge: Pictures versus Words Pictures in Your Mind: Mental Imagery Dual-Code Theory: Images and Symbols Storing Knowledge as Abstract Concepts: Propositional Theory What Is a Proposition? Using Propositions Do Propositional Theory and Imagery Hold Up to Their Promises? Limitations of Mental Images Limitations of Propositional Theory Mental Manipulations of Images Principles of Visual Imagery Neuroscience and Functional Equivalence Mental Rotations How Does Mental Rotation Work? Intelligence and Mental Rotation Neuroscience and Mental Rotation Gender and Mental Rotation Zooming in on Mental Images: Image Scaling Examining Objects: Image Scanning Representational Neglect Synthesizing Images and Propositions Do Experimenters’ Expectations Influence Experiment Outcomes? Johnson-Laird’s Mental Models Neuroscience: Evidence for Multiple Codes Left Brain or Right Brain: Where Is Information Manipulated? Two Kinds of Images: Visual versus Spatial Spatial Cognition and Cognitive Maps Of Rats, Bees, Pigeons, and Humans Rules of Thumb for Using Our Mental Maps: Heuristics Creating Maps from What You Hear: Text Maps Key Themes Summary Thinking about Thinking: Analytical, Creative, and Practical Questions Key Terms Media Resources 269 270 CHAPTER 7 � The Landscape of Memory: Mental Images, Maps, and Propositions Here are some of the questions we will explore in this chapter: 1. What are some of the major hypotheses regarding how knowledge is represented in the mind? 2. What are some of the characteristics of mental imagery? 3. How does knowledge representation benefit from both images and propositions? 4. How may conceptual knowledge and expectancies influence the way we use images? n BELIEVE IT OR NOT CITY MAPS OF MUSIC FOR THE BLIND Howcanapersonwhoisblindfindhisorherwayaround in a new city? Well, not too far in the future they may be abletoheartheirwayaroundbymeansofatranslationof descending scale. Listeners can scan an entire scene or zoom in to see the details of an object. The resulting music sounds a little like modern music. However, this only works for people who were once able to see because the landscape into music. Researchers are developing a they once developed the ability to create three- handheld device that helps blind persons navigate their environment with their ears (Cronly-Dillon et al., 2000). Just like a musical score is made up of black dots in a particular spatial distribution and are then transformed into music by a musician, the pixels in a digital image can be transformed into music as well. Listeners explore the musi-cal landscape and create a mental image of what they see. The picture is read from the left to the right; a horizon-tal line is played as one continuous note, a vertical line is played as a fast chord of many notes, and a diagonal line from the top left to the bottom right can be heard as a dimensional mental images. For example, in one study, blind subjects were able to distinguish trees, different buildings (like Victorian or modern houses and churches), or various types of cars. The blind subjects communicated their mental images to the researchers by drawing. In Figure 7.1, you can see the original images of two cars, processed images that were analyzed by the blind subjects, and the pictures of the mental images they drew. In this chapter, we will explore the representation of knowledge in our minds—in words as well as in images. Figure 7.1 How People Who Are Blind Form Mental Images. Source: Cronly-Dillon, J., Persaud, K. C., & Blore, R. (2000). Blind subjects construct conscious mental images of visual scenes encoded in musical form. Proceedings of the Royal Society B: Biological Sciences, 267, 2231–2238. Mental Representation of Knowledge 271 Look carefully at the photos depicted in Figure 7.2. Now cover the photos and describe to yourself what two of these people look like and sound like. Clearly, none of these people can truly exist in a physical form inside your mind. How are you able to imagine and describe them? You must have stored in your mind some form of mental representation, something that stands for these people-of what you know about them. What you use to recall these celebrities is more generally called knowledge re-presentation, the form for what you know in your mind about things, ideas, events, and so on, in the outside world. This chapter explores how knowledge is stored and represented in our minds: � First, we consider what representations are and in what form they can be stored. � Second, we will look at theories that describe knowledge representation and suggest that we store our knowledge in images, symbols, or propositions. � Third, we look more closely at images in our mind. How can we rotate or scan them; in short, how can we manipulate mental images? � Fourth, we examine whether separate theories regarding images and propositions can be combined as one approach. � Last, we look at mental maps. Mental Representation of Knowledge Ideally, cognitive psychologists would love to observe directly how each of us repre-sents knowledge. It would be as if we could take a videotape or a series of snapshots of ongoing representations of knowledge in the human mind. Unfortunately, direct empirical methods for observing knowledge representations are not available at pres-ent. Also, such methods are unlikely to be available in the immediate future. When direct empirical methods are unavailable, several alternative methods remain. We can ask people to describe their own knowledge representations and knowledge-representation processes: What do they see in their minds when they think of the Statue of Liberty, for example? Unfortunately, none of us has conscious access to our own knowledge-representation processes and self-reported information about these processes is highly unreliable (Pinker, 1985). Therefore, an introspectionist approach goes only so far. Another possibility for observing how we represent knowledge in our minds is the rationalist approach. In this approach, we try to deduce logically how people represent knowledge. For centuries, philosophers have done exactly that. In classic epistemology—the study of the nature, origins, and limits of human knowledge— philosophers distinguished between two kinds of knowledge structures. The first type of knowledge structure is declarative knowledge. Declarative knowledge refers to facts that can be stated, such as the date of your birth, the name of your best friend, or the way a rabbit looks. Procedural knowledge refers to knowledge of pro-cedures that can be implemented. Examples are the steps involved in tying your shoelaces, adding a column of numbers, or driving a car. The distinction is between knowing that and knowing how (Ryle, 1949). These concepts will be used later in the chapter. There are two main sources of empirical data on knowledge representation: stan-dard laboratory experiments and neuropsychological studies. In experimental work, researchers indirectly study knowledge representation because they cannot look 272 CHAPTER 7 � The Landscape of Memory: Mental Images, Maps, and Propositions Figure 7.2 Mental Representations. Look at each of these photos carefully. Next, close your eyes, and picture two of the people represented—people whom you recognize from reports in the media. Without looking again at the photos, mentally compare the appear-ances of the two people you have chosen. To compare the people, you need to have a mental representation of them in your mind. Mental Representation of Knowledge 273 into people’s minds directly. They observe how people handle various cognitive tasks that require the manipulation of mentally represented knowledge. In neuropsychological studies, researchers typically use one of two methods: (1) they observe how the normal brain responds to various cognitive tasks involving knowledge representation, or (2) they observe the links between various deficits in knowledge representation and associated pathologies in the brain. In the following sections, we explore some of the theories researchers have pro-posed to explain how we represent and store knowledge in our minds: � First, we consider what the difference is between images and words when they are used to represent ideas in the outside world, such as in a book. � Then we learn about mental images and the idea that we store some of our knowledge in the form of images. � Next, we explore the idea that knowledge is stored in the form of both words and images (dual-code theory). � Finally, we consider an alternative—propositional theory—which suggests that we actually use an abstract form of knowledge encoding that makes use of nei-ther words nor mental images. Communicating Knowledge: Pictures versus Words Knowledge can be represented in different ways in your mind: It can be stored as a mental picture, or in words, or abstract propositions. In this chapter, we focus on the difference between those kinds of knowledge representation. Of course, cognitive psychologists chiefly are interested in our internal, mental representations of what we know. However, before we turn to our internal representations, let’s look at ex-ternal representations, like books. A book communicates ideas through words and pictures. How do external representations in words differ from such representations in pictures? Some ideas are better and more easily represented in pictures, whereas others are better represented in words. For example, suppose someone asks you, “What is the shape of a chicken egg?” You may find drawing an egg easier than describing it. Many geometric shapes and concrete objects seem easier to represent in pictures rather than in words. However, what if someone asks you, “What is justice?” De-scribing such an abstract concept in words would already be very difficult, but doing so pictorially would be even harder. As Figure 7.3(a) and Figure 7.3(b) show, both pictures and words may be used to represent things and ideas, but neither form of representation actually retains all the characteristics of what is being represented. For example, neither the word cat nor the picture of the cat actually eats fish, meows, or purrs when petted. Both the word cat and the picture of this cat are distinctive representations of “catness.” Each type of representation has distinctive characteristics. As you just observed, the picture is relatively analogous (i.e., similar) to the real-world object it represents. The picture shows concrete attributes, such as shape and relative size. These attributes are similar to the features and properties of the real-world object the picture represents. Even if you cover up a portion of the figure of the cat, what remains still looks like a part of a cat. Under typical circumstances, most aspects of the picture are grasped simultaneously; but you may scan the picture, zoom in for a closer look, or zoom out to see the big picture. Even when scanning or ... - tailieumienphi.vn