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Visual Imagery I’m going to ask you a question.

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1 Visual Imagery I’m going to ask you a question.
Which room in your house (or dorm) is closest to downtown Atlanta? How did you figure the answer out? Most people will use visual imagery, or picturing the layout in their heads Visual imagery is just a visual sensation when there are no inputs to the sensory system In other words, you make them yourself You would probably do the same thing if someone asked you if elephant ears are round or pointy Now let me ask you this: do you think images are necessary for thought to occur? Can we think without images? Some people have a lot of difficulty picturing things in their heads, and they seem to still think You could look at imagery as another way that we use to solve problems However, it is very difficult to study, b/c the images exist only in a persons head

2 Mnemonics and Memory Codes
Method of loci Mnemonics: strategies to help retain and retrieve information We’ll start out talking about mnemonics b/c that will let us discuss a theory about how visual imagery might work I’ll start out with a gruesome story There was a greek poet entertaining some dinner guests, he gets called out of room, while he’s gone the roof collapses Killed everyone in the room, damaging the bodies so badly that relatives could not figure out which body was which So poet reported where he remembered everyone sitting That’s where the greeks got the idea of using something called the method of loci to help remember information For it to work as a memory aid you need to have some locations that have a logical order or sequence Then you need to have a list of information that you want to remember; pieces cannot be too big Let’s say i have a bunch of errands to run today that i want to remember Going to the bank, the gym, the post office, picking up the dry cleaning I could image that as i’m walking out the door, i trip over this big exercise bike that’s in the hallway. Then i could image walking to my car and having a shadow, wind passing over me as someone sends a huge paper airplane over my head (which is made out of an air mail envelop), getting into my car, which happens to be a bright gold color and the car itself is shaped like a dollar sign on its side. Then maybe as i’m driving i get into a car accident, my airbag pops out, smothering me, which always reminds me of that thin plastic wrap that they put dry cleaning in If i try to imagine all of this in detail, and go over the whole episode a few times, i’m more likely to remember what i needed to

3 Mnemonics and Memory Codes
Interacting images Pipe: Goat Tree: Boat Interacting images – if you are given word pairs, like goat-pipe or boat-tree If you image a goat smoking a pipe, or a boat rammed into a tree, you will remember them better than if you simply tried to remember the pair with no visualization

4 Mnemonics and Memory Codes
Pegboard method one two Pegboard method – you have a list that is easy to remember, ex. counting and words that rhyme Four – door Five – hive Six – sticks Seven – heaven Eight – gate Nine – wine Ten – hen Then you image item like bun interacting with the item you need to remember Let’s say we need some things from the store: butter, milk, eggs How would you combine them with these items to form images? three

5 Mnemonics and Memory Codes
Dual-Coding Hypothesis Now one of the biggest question about visual imagery is why does it work so well as a memory aid Dual-coding hypothesis: there are two ways of coding information in memory 1. verbal – item’s abstract, linguistic meaning 2. visual – what item looks like For some words we store only verbal, some only visual, some both Usually a very concrete item has both types of coding (tree), whereas more abstract words have only the verbal encoding (love) And items with two codes are more likely to be remember than objects with one code, so doing active visualizing helps us create both codes for items that are less concrete

6 Empirical Investigations
Symbolic Distance Effect In what other ways to we use imagery? Does it have to be an effortful process? There are lots of other ways we use imagery in day-to-day living Demo (handouts): Symbolic distance effect Give handout 1 to halve, handout 2 to half Give them face down, ask students not to turn over until they get the signal After you turn the paper over, I want you to read the directions and fill out the questions as quickly as possible. Then put your pencil down and raise your hand. Expected results: handout 1 side hands will go up first Why? for handout 1, the object pairs are very different sizes, handout 2 had pairs that were more similar in size Called the symbolic distance effect (symbolic to indicate that items are images or symbolic of real item) So there are times that we picture different items when we are thinking about them

7 Empirical Investigations
Mental Rotation Mental rotation – lots of different ways of doing this participants shown a drawing of a three-dimensional item like these block figures Asked to decide which one is the same Important finding: the amount of time it took people to decide was directly proportional to the degree of the angle that the item was turned, as if they had to mentally turn the object to answer question

8 Empirical Investigations
Mental Rotation There is another question to be asked here Are participants rotating the whole object or just part of it? Experimenters made polygons like you see here, with a different number of corners, 6, 8, 12, 16, 24 Then they also made mirror images of each polygon Subjects first learned to tell the difference between the original polygon and mirror image Then they were shown one of the polygons (original or mirror) with polygon rotated And they had to decide if they were seeing the original polygon or the mirror one Same result as before – amount of time to do the task depended on degree of rotation Now this is the important part: if Ps had just been rotating part of the figure, the polygons with more points (hence more complexity) should have taken them longer to complete than the simpler ones But instead, they treated complex polygons exactly the same as simple ones; they were rotating entire image

9 Empirical Investigations
Scanning Images Another question has to do with whether we store spatial relationships between different parts of the image in memory So, for example, when i think about how many windows are on my house, do I include the distance between each window in my image? This study tried to answer that question Fictitious map with seven locations on it Participants told to memorize them Then asked to concentrate on one location (map gone) And to move a black dot from this location to a second location and to hit a button when they arrived there Reaction times were correlated with distance Instructions: take out a big piece of blank paper and draw a map of campus from memory

10 Another example, we usually think of N america as being directly south of S america
So we do make mistakes when recording spatial info in images, b/c we like to make things “line up” Easier to remember them that way

11 Nature of Mental Imagery
Finke’s Principles Implicit Encoding Perceptual Equivalence Spatial Equivalence Transformational Equivalence Structural Equivalence Finke’s Principles – ways in which mental images are treated like photographs Implicit Encoding – we sometimes store information without even knowing it, like how many cabinets are in our kitchen – knowledge does not have to be explicit Perceptual Equivalence – we use the same neural mechanisms to both experience a real example of the image as we do to image the image in our heads later Spatial Equivalence – when we encode information in a mental image, we also record the location, distance, and size of the items in the image Transformational Equivalence – objects in images will move the same way as in real space (mental rotation) Structural Equivalence – images are formed piece by piece, the same way we would draw them; it will take more time to imagine a complicated figure than a simple figure without details

12 Nature of Mental Imagery
Critiques Research Technique Problems Tacit Knowledge Demand Characteristics Experimenter Expectancy Effects Critiques Research Technique Problems – problems with all the studies we have talked about, studies which are supposed to tell us how mental imagery works In other words, because of the problems i am going to tell you about, some of the results may not really show how mental imagery occurs Tacit Knowledge – sometimes there is something about the task that makes it obvious what is supposed to happen Ex. if someone asks you to mentally rotate an object, you might assume that they mean to do it the way you would in real life, not the way you would normally do it, so of course results are going to support idea that we mentally rotate objects like we do in real life, and we just “pause” until enough time has gone by Demand Characteristics – sometimes participants will guess type of results the experimenters want to find, and there is a natural impulse to please the experimenter, so they perform in a way to conform to experimenters hopes (either consciously or unconsciously); importance distinction – what participants believe Experimenter Expectancy Effects – other side of the picture; sometimes experimenters can communicate what they want from participants, so participants perform in that way; importance distinction – what experimenters believe Exp. To test experimenter expectancy effects Group of participants whose had to do 1) an image scanning task, like the one with the map and mentally tracing routes and 2) a mental rotation task Each participant had to do both tasks in two different ways, one where the stimuli were physical present for a brief time, one where they had to think about mental image before the task The real part of the experiment had to do with the people who were supervising the participants, the “experimenters” themselves; half led to believe that the participants would do better on the physical priming version, half that the Ps would do better with the mental imagery version It turned out that those experimenters who thought the physical version Ps would do better actually did do better on the task, and vice versa But there was no difference in the tasks themselves Tapes revealed that experimenters were reading the instructions for the version that they thought would have better performance more slowly and clearly

13 Nature of Mental Imagery
Critiques Picture Metaphor Critiques Picture Metaphor – is a visual image really a mental picture? Differences: You can look at a photograph and not know what you are looking at; for mental image, you must know what the image is before you can “see” it You can change the two items differently; photo you can cut in half, mental image, you cannot do this, if parts of image disappear, they are parts that are deemed unimportant

14 Nature of Mental Imagery
Critiques Picture Metaphor Critiques Picture Metaphor – is a visual image really a mental picture? Differences: You can look at a photograph and not know what you are looking at; for mental image, you must know what the image is before you can “see” it You can change the two items differently; photo you can cut in half, mental image, you cannot do this, if parts of image disappear, they are parts that are deemed unimportant Mental images are more susceptible to changes based on interpretations than photos Exp. Subjects given an ambiguous drawing, told to memorize it, but drawing had a label by it, two different possibilities Later asked to draw items, they were distorted subtly by how Ps thought items should look So, metaphor only works roughly, not an exact match

15 Nature of Mental Imagery
Critiques Propositional Theory Critiques – third one Propositional Theory – original mental imagery idea is that mental images are a special type of encoding; prop theory says this is not true, that there is only one kind of encoding, which is neither visual nor verbal Pylyshyn suggested that the experience of having a mental image is really just an epiphenomenon (something that happens with a process, but that does not cause the process, instead is just a by-product – without the epiphen. The process would go on just like normal – not necessary for process to occur) Ex. when computer is calculating something, it often has a flashing light, but flashing light has nothing to do with the actual computation; if light blew out, computation will still happen, so trying to understand how and why the light comes on and flashes will not tell us anything about how the computations are occurring Instead, the encoding is propositional – concepts are stored as symbols, and what is stored is not a physical relationship, but a conceptual one, like the network models of memory

16 Nature of Mental Imagery
Critiques Propositional Theory REAR DECK (behind) CABIN (behind) FRONT DECK (top of) (side of) (front, side of) (back of) Instead, the encoding is propositional – concepts are stored as symbols, and what is stored is not a physical relationship, but a conceptual one, like the network models of memory So it would make sense that trying to scan a path from the flag at the back of the boat to the cabin would take less time than scanning from the flag to the emblem, since you would have more nodes to go thru (2 vs. 4) So it is possible to explain scanning times without having to use a mental image RECTANGLE FLAG LONG FLAG PORTHOLE EMBLEM (left of) (right of) STARS STRIPES

17 Neuropsychological Findings
Exp. 1: three tasks during brain imaging Exp. 2: creating mental images Exp. 3: faces vs. locations fusiform face area parohippocampal place area Exp. 1: three tasks during brain imaging Mental arithmetic 2. scanning an audio stimulus mentally 3. walking thru a familiar neighborhood (visual scanning) Activation of visual cortex for visual scanning but not for other two tasks Exp. 2: creating mental images Ps told to imagine previously memorized line drawings, sometimes as small, medium, or large Visual cortex lit up, but also, amount of cortex activated depended on size of mental image Exp. 3: faces vs. locations If faces imagined, fusiform face area activated, same as if photos of faces seen if locations, parohippocampal place area activated, same as in photos of locations Demand characteristics less likely to be at play here b/c it would mean that Ps would have to know which brain areas should be activated by which stimuli, and be able to activate those areas voluntarily

18 Spatial Cognition Cognitive Map Types of spatial cognition:
Space of the body Space around the body Space of navigation Spatial cognition – some people have suggested that there is also something unique about maps of spatial locations that we have in brains, which we use to navigate thru environments in real time – call it cognitive map Ex. i went to an appointment today, ended up turning on the wrong road, my internal map was faulty My chinchilla: change something in cage, has to jump around on things a few times to experiment with distances Types of spatial cognition: Space of the body – knowledge of where different parts of your body are located at any given moment, and internal body sensations (stuffy head, rumbling stomach) – so that i will know how to successfully interact with items in the environment Space around the body – knowledge of location of objects immediately around you Space of navigation – knowledge of locations of objects that you may not be able to see immediately, usually large area – places/road in Buckhead for example

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