Mental Imagery

Mental Imagery ______________________________________ 1) Define mental imagery and give examples from several sensory modalities. 2) Describe the distinction between the two major models of imagery representation • analog • propositional 3) Define the concept of functional equivalence, its relationship to the analog/propositional debate, and discuss empirical evaluations of its predictions. 4) Explain how analog and propositional information contribute to cognitive maps of the world. 5) Examine the neuropsychological approach to investigating mental imagery. 6) Discuss practical applications of mental imagery including its use a mnemonic technique. Mental Imagery _______________________________________ Imagery - a mental representation of an object that is not physically present. a) Visual Images b) Auditory Images c) Tactile, Olfactory, Gustatory d) Motor Imagery e) Emotional Imagery Key questions: 1. How are images represented? 2. Relationship to true perception. 3. Individual Differences. The Great Representation Debate: Analog vs. Propositions ______________________________________ Analog Code: Images take a form very similar to the actual, physical object (Hint: analogy) Kosslyn: Visual images are literally pictures in the brain. We have an internal movie theater in our heads. There is an internal camera that projects the image, an internal screen that receives the image and an internal eye the views the image. Propositional Code: Images are constructed using abstract, verbal descriptions. Pylyshyn: Images are an epiphenomenon. We don’t spontaneously generate them. They appear to us as a consequence of activating the propositions that describe an object and we only use them under highly constrained situations. Contrasting the two positions ___________________________________________ How do you get from Fayerweather to your dorm? Analog Propositional Left, left, right, left Contrasting the two positions ___________________________________________ How do you know when chocolate chip cookies are done? 1. Analog 2. Propositional Not so much… Studying Imagery?? ______________________________________ Problem #1: Unobservable process. Solution #1: Measure reaction time EX: Form an image of a cow Raise your hand when you are done. ______________________________________ Problem #2: Interpreting RT RT varies indirectly with ability. RT varies directly with level of detail. Level of detail varies directly with ability. Solution #2: Measure RT and accuracy EX: Ask people to manipulate an object in their heads and ask verifiable questions. (e.g., Shepard & Metzler, 1971) Functional Equivalence _______________________________________ Functional equivalence - Although images are not identical to perception or real objects, images should behave the same way as real objects. Predictions: 1) Imaged objects should follow the same laws of time and space as physical objects. 2) The relations of elements of a visual image should be analogous to those of an actual object. 3) We should be able to infer information from mental images that were not specifically stored at encoding. 4) The construction of mental images should be analogous to the construction of visually perceptible figures. 5) The brain structures that are used to perceive objects should be largely the same as those used to image objects. Rotation Studies: Shepard & Metzler (1971) ________________________________________ Theoretical Question: Empirical Question: Method: • Why did they choose unfamiliar objects? • Picture Plane and depth Results: More on Shepard & Metzler (1971) ______________________________________________ CogLab results 3500 3000 RT 2500 2000 Same Different 1500 1000 500 0 0 20 40 60 80 Angle of rotation Implications: Related Findings: • Object variables • Effects of SOA • Rotation vs. description 100 120 Individual Differences in Imagery _______________________________________ People with good spatial ability are much faster than people with bad spatial skills. Grain Size _______________________________________ Imagine an elephant standing next to a rabbit. Q1: Imagine a mouse standing next to a rabbit? Q2: ______________________________________ Typically, people answer Q2 faster than Q1. Why? Images are like real-life objects in that the image that people form of the rabbit in part 1 is smaller than the image of the rabbit that people form in part 2. Quibblings Q: Is it something about flies and elephants? A: Similar results if rabbit is imaged next to a monstrous fly or next to a miniscule elephant. Q: Is it something about the time to construct large vs. small images? A: No. Large images take longer to construct. Symbolic Distance Effect ___________________________________________ Which is larger a: man or a mouse? moth or a bird? moose or a mouse? man or a moose? dog or a cat? horse or a cow? Clock Images ___________________________________________ Imagine two standard non-digital clocks. For each pair, choose the time that creates the smaller angle between the hour and minute hands? 1) 4:10 vs. 9:23 2) 3:20 vs. 7:25 3) 2:45 vs. 1:05 4) 3:15 vs. 5:30 Imagery Fusion Studies ______________________________________ Exercise #1: Construct an image of a capital letter M, and an image of an inverted capital letter M. Align the two images so that the bottoms (3-point ends) touch. What do you have? Exercise #2: Superimpose an image of a capital letter X with an image of a capital letter H. What do you have? Mental Maps ___________________________________________ Imagery and Vision: Dual-Task Costs ___________________________________________ Any visual task becomes much more difficult if I ask you to do a concurrent imagery task (and vice versa). Task 1 ODUGQR QCDUGO CQOGRD QUGCRD URDGQO GRUQDO DUZGRO UCEROC DQRCGU QDOCGU UOCGQD Task 2 RGQCOU GRUDQO GODUCQ QCURDO DUCOQG CGRDQU UDRCOQ GQCORU GODUCD CDQUOC URDCGO Starting at Bart's and walking South (back towards campus), what is the fourth store on the West side of Pleasant Street? Where does functional equivalence stand? ___________________________________________ 1) Imaged objects should follow the same laws of time and space as physical objects. Evidence: 2) The relations of elements of a visual image should be analogous to those of an actual object. Evidence: 3) We should be able to infer information from mental images that were not specifically stored at encoding. Evidence: 4) The construction of mental images should be analogous to the construction of visually perceptible figures. Evidence: 5) The brain structures that are used to perceive objects should be largely the same as those used to image objects. Evidence: Cube Demonstration ______________________________________________ Grasp the left, front, bottom corner of a cube with your left hand, and the right, rear, upper corner with your right hand. Mentally rotate the cube so that the corner in your left hand is directly below the corner in your right hand. How many corners of the imaginary cube are in the middle plane (i.e., not being grasped by your hands? More on Maps ___________________________________________ Which is further west: • Los Angeles or San Diego? • San Diego or Reno, NV? • New York or Miami? Which is a longer trip: • Philadelphia • New York • Miami Pittsburgh, Richmond, VA? Pittsburgh Richmond, VA? New York Columbus, OH? Which is farther north: Rome or Philadelphia? Draw an outline of the state of South Carolina. Draw a map of the United States? ______________________________________________ Explanations: • Alignment heuristic • Symbolic Distance Effects • Rotation heuristic Even more on Maps ___________________________________________ Compromise Position ___________________________________________ Two types of representation Surface / Analog representation • Accounts for picture-like quality Deep / Propositional representation • used to handle more difficult tasks. • arbitrary relationship between what is represented and how it is represented. Neuropsychology and Imagery ______________________________________________ Prediction of Functional Equivalence? Martha Farah Group 1: Read a list of concrete words Group 2: Read and image same list Measure ERPs Results: No difference for first half-second More occipital lobe activity in Group 2 Two Component model Visual - physical appearance of an object EX: Which states share shape: NC, VA, CO? Spatial - relationships between different objects EX: Which states are closest: FL, GA, MO? Data: • Patient (LH) show spared ability to answer visual question, but deficit on spatial questions. • LH could copy objects he could not name. Implication: naming = physical info + assembly Practical Applications of Imagery ___________________________________________ Therapy • Systematic desensitization • Guided imagery (recovered memories) Athletics • Typing Art • Painting • Literature - See the movie or not? School • Visit your professors Imagery as a Mnemonic Device: ___________________________________________ Pegword system One-Bun Six-Sticks Two-Shoe Seven-Heaven Three-Tree Eight-Gate Four-Door Nine-Dime Five-Hive Ten-Hen ______________________________________________ What Makes Imagery Work? o Bizarreness? o Interactivity