Hockenbury Discovering Psychology 5th txtbk

278 CHAPTER 7 Thinking, Language, and Intelligence1.1seconds1.7 seconds1.9 seconds1.6 seconds1.4 secondsFigure 7.1 Mentally Scanning ImagesThis is a reduced version of the map usedby Stephen Kosslyn and his colleagues(1978) to study the scanning of mentalimages. After subjects memorized themap, the map was removed. Subjects thenmentally visualized the map and scannedfrom one location to another. As you cansee by the average scanning times, it tooksubjects longer to scan greater distanceson their mental images of the map, just asit takes longer to scan greater distances onan actual map.Do people manipulate mental images in the same way that they manipulate theirvisual images of actual objects? Suppose we gave you a map of the United States andasked you to visually locate San Francisco. Then suppose we asked you to fix yourgaze on another city. If the other city was far away from San Francisco (like NewYork), it would take you longer to visually locate it than if it was close by (like LosAngeles). If you were scanning a mental image rather than an actual map, would italso take you longer to scan across a greater distance?In a classic study by Stephen Kosslyn and his colleagues (1978), participants firstviewed and memorized a map of a fictitious island with distinct locations, such asa lake, a hut, and grass (see Figure 7.1). After the map was removed, participantswere asked to imagine a specific location on the island, such as the sandy beach.Then a second location, such as the rock, was named. The participants mentallyscanned across their mental image of the map and pushed a button when theyreached the rock.The researchers found that the amount of time it took to mentally scan to thenew location was directly related to the distance between the two points. Thegreater the distance between the two points, the longer it took to scan the mentalimage of the map (Kosslyn & others, 1978). It seems, then, that we tend to scan amental image in much the same way that we visually scan an actual image (Kosslyn& Thompson, 2000).However, we don’t simply look at mental images in our minds. Sometimes thinkinginvolves the manipulation of mental images. For example, try the problem inFigure 7.2 at the bottom of the page, and then continue reading.It probably took you longer to determine that the 3 in the middle was backwardthan to determine that the 3 on the far left was backward. Determining which 3swere backward required you to mentally rotate each one to an upright position. Justas it takes time to rotate a physical object, it takes time to mentally rotate an image.Furthermore, the greater the degree of rotation required, the longer it takes you torotate the image mentally (Wohlschläger & Wohlschläger, 1998). Thus, it probablytook you longer to mentally rotate the 3 in the middle, which you had to rotate180 degrees, than it did to mentally rotate the 3 on the far left, which you had torotate only 60 degrees.Collectively, research seems to indicate that we manipulate mental images muchas we manipulate the actual objects they represent (Rosenbaum & others, 2001).However, mental images are not perfect duplicates of our actual sensory experience.The mental images we use in thinking have some features in common with actualvisual images, but they are not like photographs. Instead, they are memories ofvisual images. And, like memories, visual images are actively constructed andpotentially subject to error (Cattaneo & Vecchi, 2008).ConceptsAlong with mental images, thinking also involves the use of concepts. A concept isa mental category we have formed to group objects, events, or situations that sharesimilar features or characteristics. Concepts provide a kind of mental shorthand,economizing the cognitive effort required for thinking and communication.Using concepts makes it easier to communicate with others, remember information,and learn new information. For example, the concept “food” might includeanything from a sardine to a rutabaga. Although very different, we can stillgroup rutabagas and sardines together because they share the central feature ofbeing edible. If someone introduces us to a new delicacy and tells us it is food,we immediately know that it is something to eat—even if it is something we’venever seen before.Figure 7.2 Manipulating Mental ImagesTwo of these threes are backward.Which ones?