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14.12.2015 Chapter 10 Imagery Some Questions to Consider • How do “pictures in your head” that you • • • Experiencing Imagery • Answer the following questions: – • How many windows are there in front of the house where you live? – • How is the furniture arranged in your bedroom? – • Are an elephant’s ears rounded or pointy? – • Is the green of grass darker or lighter than the green of a suit used in military service? create by imagining an object compare to the experience you have when you see the actual object? What happens in your brain when you create visual images with your eyes closed? How does damage to the brain affect the ability to form visual images? How can we use visual imagery to improve memory? What Is Imagery? • Mental imagery: experiencing a sensory impression in the absence of sensory input • • – Visual imagery: “seeing” in the absence of a visual stimulus What about auditory imagery? Imagine all the people living life in peace... 1 14.12.2015 Imagery and the Cognitive Revolution • Developed ways to measure behavior that could be used to infer cognitive processes – Paired-associate learning • boat–hat or car–house • Alan Paivio (1963): it was easier to remember concrete nouns, like truck or tree, that can be imaged, than it is to remember abstract nouns, like truth or justice, that are difficult to image. Imagery and the Cognitive Revolution Imagery and the Cognitive Revolution • Paivio (1963, 1965) – Paivio inferred cognitive processes by measuring memory – Memory for words that evoke mental images is better than those that do not – Conceptual-peg hypothesis • concrete nouns create images that other words can “hang onto.” boat-hat Task: to indicate, as rapidly as possible, whether the two pictures were of the same object or of different objects. • Shepard and Meltzer (1971) – inferred cognitive processes by using ‘Mental chronometry’: the amount of time needed to carry out cognitive tasks – Participants mentally rotated one object to see if it matched another object Caption: Stimuli for Shepard and Metzler’s (1971) mental rotation experiment. 2 14.12.2015 Mental rotation by Shepard. Q: these are the same or not? The time it takes to do this task depends on how different the angles were between the two views. http://bjornson.inhb.de/?p=55 Imagery and Perception Imagery and Perception • Do imagery and perception share the same mechanisms? • Although mental images are not vivid or long lasting as perception... • Kosslyn: participants create mental images and then scan them in their minds. (Mental scanning) • We act as if our mental images are physical entities – Scanning – Acuity • Kosslyn (1973) – Memorize picture, create an image of it – In image, move from one part of the picture to another Caption: Stimulus for Kosslyn’s (1973) imagine-scanning experiment. 3 14.12.2015 Imagery and Perception • Kosslyn (1973) • Q: Perception is spatial. What about imagery? Is imagery spatial or not? • It took longer for participants to mentally move long distances than shorter distances Imagery and Perception • Lea (1975) opposite to Kosslyn – More distractions (other interesting parts, such as the cabin) when scanning longer distances may have increased reaction time – Like perception, imagery is spatial Imagery and Perception • So, Kosslyn et al. (1978) did another experiment – Imagine an island with 7 locations, Imagery and Perception – It took longer to scan between greater distances – Visual imagery is spatial – scan between two places on a map (21 possible mental Trips Participants mentally traveled between the various locations on the island. 4 14.12.2015 Is Imagery Spatial or Propositional? • Kosslyn: mechanism responsible for imagery involves a spatial representation • But Pylyshyn (1973) disagreed. • Spatial representation is an epiphenomenon. something is happening in the mind, but don’t tell us how it is happening. • • – Accompanies real mechanism but is not actually a part of it. Analogy: The lights may indicate that something is going on inside the computer, but they don’t necessarily tell us what is actually happening. Proposed that imagery is propositional – Can be represented by abstract symbols Caption: Propositional and spatial, or depictive, representations of “the cat is under the table.” Is Imagery Spatial or Propositional? • Pylyshyn (1973) – Imagery debate • Proposition representation: symbols, language • Spatial representation: pictures The words indicate parts of the boat, the length of the lines indicate the distances between the parts, and the words in parentheses indicate the spatial relations between the parts! This is how the visual appearance of this boat can be represented propositionally 5 14.12.2015 Is Imagery Spatial or Propositional? • Finke and Pinker (1982) – Participants judge whether arrow points to dots previously seen – Longer reaction time when greater distance between arrow and dot (as if they were mentally “traveling”) Comparing Imagery and Perception • Size in the Visual Field • how imagery is affected by the size of an object in a person’s visual field. – Not instructed to use visual imagery – No time to memorize, This is what happens during perception process? What about imagery? Comparing Imagery and Perception • Relationship between viewing distance and ability to perceive details (happens in imagery?) Kosslyn – Imagine small animal next to large animal • ‘Does a rabbit have whiskers?’ asked his • participants to find that part of the animal in their mental image and to answer as quickly as possible answered question about the rabbit more rapidly when it filled more of the visual field. So, Quicker to detect details on the larger animal. Caption: These pictures represent images that Kosslyn’s (1978) participants created, which filled different portions of their visual field. (a) Imagine elephant and rabbit, so elephant fills the field. (b) Imagine rabbit and fly, so rabbit fills the field. Reaction times indicate how long it took participants to answer questions about the rabbit. 6 14.12.2015 Comparing Imagery and Perception • Mental-walk task • • – imagine that they were walking toward their mental image of an animal. Their task was to estimate how far away they were from the animal when they began to experience “overflow”—when the image filled the visual field Move closer to small animals than to large animals – Images are spatial, like perception Even more interesting, not one of Perky’s 24 participants noticed that there was an actual picture on the screen. Mistake actual picture for a mental image Interactions of Imagery and Perception • How do they interact with one another? • Perky (1910) • Perky asked her participants to “project” visual • • images of common objects onto a screen, and then to describe these images. Perky was back-projecting a very dim image of this object onto the screen Interestingly, the participants’ descriptions of their images matched the images that Perky was projecting. Martha Farah (1985) instructed her participants to imagine either the letter H or T on a screen. They pressed a button that caused two squares to flash, one after the other. One of the squares contained a target letter, which was either an H or a T. The participants’ task was to indicate whether the letter was in the first square or the second one. Caption: Participant in Perky’s (1910) experiment. Unbeknownst to the participants, Perky was projecting dim images onto the screen. Result: The target letter was detected more accurately when the participant had been imagining the same letter rather than the different letter. perception and imagery share mechanisms. 7 14.12.2015 NEUROPSYCHOLOGICAL CASE STUDIES Removing Part of the Visual Cortex Decreases Image Size NEUROPSYCHOLOGICAL CASE STUDIES Removing Part of the Visual Cortex Decreases Image Size – Patient M.G.S. (her right occipital lobe removed) – Martha Farah and et al. (1993) had M.G.S. perform the mental walk task! – Before the operation: M.G.S. was about 15 feet from an imaginary horse before its image overflowed. Why? because removing part of the visual cortex reduced the size of her field of view, so the horse filled up the field when she was farther away! – After the operation: it was 35 feet. Dissociations between Imagery and Perception NEUROPSYCHOLOGICAL CASE STUDIES • Damage to the parietal lobes can • cause a condition called unilateral neglect. The patient neglected the left side of his mental image, just as he neglected the left side of his perceptions. • one function present and another function absent! • Guariglia and coworkers (1993) • – Brain-damaged patient – Patient’s perceptions intact, but mental images were impaired R.M. (normal perception but impaired imagery) – Damage to occipital and parietal lobes – Could draw accurate pictures of objects in front of him – Could not draw accurate pictures of objects from memory (using imagery) – Problem at on imagery: “A grapefruit is larger than an orange” 8 14.12.2015 Dissociations between Imagery and Perception • C.K. (perception is impaired but imagery is normal) – Visual agnosia (the inability to visually recognize objects.) – Could draw objects in great detail from memory (using imagery) – Inability to name pictures of objects, even his own drawings, in front of him Making Sense of Neuropsychological Results • Evidence for a double dissociation between imagery and perception – Indicates separate mechanisms. • Also evidence for shared mechanisms Explains C.K. and R.M. but not M.G.S. Making Sense of Neuropsychological Results • Behrmann and coworkers (1994) – Mechanisms partially overlap – Visual perception involves bottom-up processing; located at lower and higher visual centers. – Imagery is a top-down process; located at higher visual centers. (in higher brain areas that are responsible for memory.) Mental images do not depend on activation of cortical areas, such as the visual cortex, because there is no input that needs to be processed. Caption: Perception are located at both lower and higher visual centers and imagery are located mainly at higher levels (Behrmann et al., 1994). The general locations of damage for C.K. and R.M. are indicated by the vertical arrows. These locations can explain why R.M. has trouble creating images but can still perceive and why C.K. has a perceptual problem but can still create images. 9 14.12.2015 Imagery and Perception • Differences in experience – Perception is automatic and stable – Imagery takes effort and is fragile Imagery and Perception • Later research has shown that people can • Chalmers and Reisberg (1985) – Perceptually, it is easy to “flip” between these two perceptions. – Had participants create mental images of ambiguous figures. – Difficult to flip from one perception to another while holding a mental image of it Using Imagery to Improve Memory • How can you use the power of imagery to help you remember things better? • Method of loci (Yerleştirme yöntemi) – Visualizing items to be remembered in different locations in a mental image of a spatial layout – Placing images at locations can help with retrieving memories later. • manipulate simpler mental images. – Ronald Finke and coworkers (1989) – imagine a capital letter D, and then rotate it 90 degrees to the left and place a capital letter J at the bottom, they reported seeing an umbrella. Imagery and perception have many features in common, but there are also differences between them. Using Imagery to Improve Memory • Method of loci 1. Pick a place with a spatial layout that is very familiar to you 2. pick 5 to 7 things that you want to remember 3. place each thinng at a location 4. try mentally “walking” this path while trying to recall 10 14.12.2015 Using Imagery to Improve Memory • Method of loci • Pegword technique (Sözcük asma) Bower (1970) Left Column Egg Cat food Tomato Banana Whiskey Using Imagery to Improve Memory Right Column garage outside garage inside front door coat hanger sink at kitchen Using Imagery to Improve Memory • Pegword technique (Sözcük asma) e.g. Bir, bir piredir.(fil) İki bir iptir. (ayakkabı) Üç bir süttür.(ağaç) Dört, bir gözdür. Beş bir balıktır. Altı bir martıdır. Yedi bir kedidir. Sekiz bir sakızdır. – Associate items to be remembered with concrete words – Pair each of these things with a pegword – Create a vivid image of things to be remembered with the object represented by the word Using Imagery to Improve Memory • Recalling Words Trabzon Trenin’de Cin Hortladı. El bileklerindeki kemiklerTrapezium, Trapezoideum, Capitutum, Havuantum Dünyanın en uzun nehirleri: Misissipi; Nil ve Sari Irmak Ma Ni Sa BAHT Temel terapi ekolleriBilişsel, Analitik, Hümanistik NEWSOCEAN – 5 Factor personality 11 14.12.2015 Using Imagery to Improve Memory • Recalling people’s names Relating the name with the face of that person. One way rhyming e.g. Erdem-demir gibi güçlü bir er Ayten-bembeyaz, ay gibi bir ten Second way finding a salient feature at the face and relating it with the name. e.g. Koca kulaklı Ayten-anten 12