Cognitive Psychology Chapter 10: Visual imagery
TEST YOURSELF 10.1 1. Is imagery just a "laboratory phenomenon," or does it occur in real life?
Imagery occurs in real and everyday life. "Imagery is undoubtedly already a part of your everyday life. If you ever worry about the future, reminisce about the past, have sexual fantasies, or make plans, you use imagery whether you know it or not — you represent these things in some way to yourself internally — and that's imagery!" https://psychcentral.com/lib/imagery-in-everyday-life/ Mental imagery is experiencing a sensory impression in the absence of sensory input. visual imagery is "seeing" in the absence of a visual stimulus. Imagery has played an important role in the creative process and as a way of thinking in addition to purely verbal techniques. (Summary 1 p.294)
IMAGERY and PERCEPTION: DO THEY SHARE the SAME MECHANISMS? ➢ Kosslyn's (1979) Mental Scanning Experiments, 279
In answer to Lea's proposal of distraction causing longer reaction time, Kosslyn did another experiment, providing more evidence for his theory that visual imagery is spatial.
IMAGERY and PERCEPTION: DO THEY SHARE the SAME MECHANISMS? ➢ The Imagery Debate: Is Imagery Spatial or Propositional?, 279 Pylyshyn (1973) disagreed with Kosslyn
Pylyshyn says that just because we experience imagery as spatial doesn't mean that the underlying representation is spatial--since we often aren't aware of our mind's processes. He calls the spatial experience of mental images an epiphenomenon..
IMAGERY and PERCEPTION: DO THEY SHARE the SAME MECHANISMS? ➢ Kosslyn's Mental Scanning Experiments, 279 Pylyshyn (1973) proposed another explanation
Pylyshyn suggested that spatial representation is an epiphenomenon--accompanies real mechanism but is not actually a part of it. This proposal lead to the imagery debate.
IMAGERY and PERCEPTION: DO THEY SHARE the SAME MECHANISMS? ➢ The Imagery Debate: Is Imagery Spatial or Propositional? , 279
Kosslyn interpreted his research results on imagery as supporting the idea that the mechanism responsible for imagery involves a spatial representation.
IMAGERY and PERCEPTION: DO THEY SHARE the SAME MECHANISMS? ➢ Comparing Imagery And Perception Size of the Visual Field Kosslyn's 1978 experiment, 282
Kosslyn wondered whether the relationship between viewing distance and the ability to perceive details also occurs for mental images. See mental walk task.
IMAGERY and PERCEPTION: DO THEY SHARE the SAME MECHANISMS? ➢ The Imagery Debate: Is Imagery Spatial or Propositional?, 280-281 Pylyshyn on Kosslyn's boat (2003)
Kosslyn's boat is a depictive representation. Figure 10.6 shows how the visual appearance can be represented propositionally--with words indicating parts of the boat, etc. Can be explained by real-world knowledge unconsciously--tacit-knowledge explanation
TEST YOURSELF 10.1 3.1 How did Kosslyn use the technique of mental scanning (in the boat and island experiments) to demonstrate similarities between perception and imagery?
Kosslyn's mental scanning experiments suggested that imagery shares the same mechanisms as perception--we create mental images and then scan them in our minds (that is, we create a depictive representation in our mind) • subjects memorized a picture of an object (like the boat), then were to create an image of the object in their mind, and then focus on one part of the boat and then asked to look for another part of the boat and press the "true" button when they found it or the "false" button if they couldn't find it Reasoning was that if imagery is spatial, then it should take longer for subjects to find parts that are located farther from the initial point of focus because they would be scanning across the image of the object. Glen Lea (1975) proposed that subjects may have encountered other interesting parts and this distraction may have increased their reaction time. Kosslyn then did another scanning experiment (1978) in which subjects scanned a distance between two locations on a map with similar results.
TEST YOURSELF 10.1 3.2 Why were Kosslyn's experiments criticized, and how did Kosslyn answer Pylyshyn's criticism with additional experiments?
Kosslyn's results and others were challenged by Pylyshyn, who stated that imagery is based on a mechanism related to language (that is, it creates a propositional representation in a person's mind.) Pylyshyn says that just because we experience imagery as spatial doesn't mean that the underlying representation is spatial. He called it an epiphenomenon--like flashing lights on a mainframe computer as it processes its data. This lead to the imagery debate--about whether imagery is based on spatial or propositional mechanisms.
TEST YOURSELF 10.1 5. What is the tacit knowledge explanation of imagery experiments? What experiment was done to counter this explanation?
One of Pylyshyn's arguments against the idea of depictive representation is the tacit knowledge explanation, which states that when asked to imagine something, people ask themselves what it would look like to see it and then simulate this staged event. Finke & Pinker "flashed dot" experiment argued against the tacit knowledge explanation.
IMAGERY and PERCEPTION: DO THEY SHARE the SAME MECHANISMS? ➢ Comparing Imagery And Perception Interactions of Imagery & Perception Perky classic demonstration (1910), 283
Rationale behind this approach is if imagery affects perception, or perception affect imagery, this means that imagery and perception both have access to the same mechanisms. ➢ Subjects mistook actual picture (very faint) for a mental image
IMAGERY IN THE HISTORY OF PSYCHOLOGY ➢ Imagery And The Cognitive Revolution Paivio's experiment (1963), 278
Paivio (1963, 1965) Memory for word that evokes mental images is better than those that do not. Proposed conceptual-peg hypothesis
TEST YOURSELF 10.2 1. Describe how experiments using the following physiological techniques have provided evidence of parallels between imagery and perception: (a) brain imaging; (b) deactivation of parts of the brain; (c) neuropsychology; and (d) recording from single neurons.
Parallels between perception and imagery have been demonstrated physiologically by the following methods: (a) recording from single neurons (imagery neurons); (b) brain imaging (demonstrating overlapping activation in the brain); (c) transcranial magnetic stimulation experiments (comparing the effects of brain inactivation on perception and imagery); and (d) neuropsychological case studies (removal of visual cortex affects image size, unilateral neglect).
TEST YOURSELF 10.1 2. Make a list of the important events in the history of the study of imagery in psychology, from the imageless thought debate of the 1800s to the studies of imagery that occurred early in the cognitive revolution in the 1960s and 1970s.
1) Wundt's first lab of psychology (1879). Proposed that images were on of the 3 basic elements of consciousness, along with sensations & feelings. (Structuralism) Proposed that because images accompany thought, studying images was a way of studying thinking. 2) Gave rise to the imageless thought debate 3) Evidence supporting idea that imagery was not required for thinking was from Galton's work (1883) observing people who had great difficulty forming visual images were still capable of thinking. 3) Behaviorists era kept study of imagery out of mainstream (1920s - 1950s) because Watson described images as "unproven" and "mythological" (1928) 4) Cognitive Revolution (1950s & 1960s) methods to measure behavior that could be used to infer cognitive processes were key. • Ex: Paivio's (1963) work on memory showing it was easier to remember concrete nouns that can be imagined than abstract nouns. Method: Paired-associate learning. Proposed conceptual peg hypothesis. • Ex: Shepard & Metzler (1971) inferred cognitive processes by using mental chronometry, determining the amount of time needed to carry out various cognitive tasks. Important because they were first to use quantitative methods.
IMAGERY and the BRAIN ➢ Brain Imaging Ganis (2004) fMRI Experiment, 286
Another approach to studying imagery and the brain has been to determine whether there is a overlap between brain areas activated by perceiving an object and those activated by creating a mental image of the object.
IMAGERY and PERCEPTION: DO THEY SHARE the SAME MECHANISMS? ➢ Kosslyn's Mental Scanning Experiments, 278 Glen Lea (1975) proposal
Another researcher who suggested the reason for the longer time in locating a part further from the initial focus point is that subject may have encountered other interesting parts, and this distraction may have decreased reaction time
TEST YOURSELF 10.2 2. Some of the psychological results demonstrate parallels between imagery and perception, and some results do not. How has Behrmann explain these contradictory results?
Berman studied C.K., is 33 year old who was struck by a car resulting in visual agnosia, the inability to visually recognize objects. C.K. could recognize parts of objects but couldn't integrate them into a meaningful whole. Behrmann explains this paradox by suggesting that the mechanisms of perception and imagery overlap only partially, with the mechanism for perception being located at both lower and higher visual centers and the mechanism for imagery being located mainly in higher visual centers. This would mean that visual perception involves bottom-up processing, which starts when light enters the yet and an image is focused on the retina, then continues as signals are sent along the visual pathways to the visual cortex and then to higher visual centers. The visual cortex is crucial for perception because it is here that objects begin being analyzed into components like edges and orientations. This information is been sent to hire visual areas, where perception is assembled, and top-down processing, which involves a person's prior knowledge, may also be involved.
IMAGERY and PERCEPTION: DO THEY SHARE the SAME MECHANISMS? ➢ Comparing Imagery And Perception Interactions of Imagery & Perception Farah's 1985 experiment, 283-284
Caption: Procedure for Farah's (1985) letter visualization experiment. a) Participant visualizes "H" or "T" on the screen. b) Then two squares flash one after the other on the same screen As shown on the right, the target letter can be in the first square or in the second one. The participants' task is to determine whether the test letter was flashed in the first or in the second square. c) Results showing that accuracy was higher when the letter in (b) was the same as the one that had been imagined in (a).
IMAGERY and the BRAIN ➢ Brain Imaging Le Bihan (1993) Experiment, 285 Early stage brain imaging experiment, 285
Demonstrated that both perception and imagery activate the visual cortex
TEST YOURSELF 10.2 5. What is the relationship between food craving and visual imagery? How has visual imagery been used to reduce food craving?
Food craving has been associated with food-related visual imagery. A reduction in food craving has been associated with non-food-related visual imagery. It has been suggested that this reduction in food craving occurs because the non-food related imagery uses some of the capacity of the visuospatial sketch pad.
IMAGERY and PERCEPTION: DO THEY SHARE the SAME MECHANISMS? ➢ Kosslyn's Mental Scanning Experiments, 278
Studied spatial correspondence between imagery and perception.
IMAGERY and the BRAIN ➢ Imagery Neurons in the Brain Single neuron in humans study, 284
Studies in which activity is recorded from single neurons in humans are rare, but Kreiman was able to study patients who had electrodes implanted in various areas in their medial temporal lobe, which includes the hippocampus and the amygdala, in order to determine the source of severe epileptic seizures that could not be controlled by medication.
IMAGERY and the BRAIN ➢ Neuropsychological Case Studies PERCEPTUAL PROBLEMS ARE ACCOMPANIED BY PROBLEMS WITH IMAGERY Bisiach & Luzzatti (1978) experiment, 288
Study of pt with unilateral neglect. Correspondence between physiology of mental imagery and the physiology of perception, as demonstrated by brain scans in normal subjects and the effects of brain damage in subjects with neglect, supports the idea that mental imagery and perception share physiological mechanisms. However, not all physiological results support a one-to-one correspondence between imagery and perception.
IMAGERY and the BRAIN ➢ Neuropsychological Case Studies REMOVING PART of the VISUAL CORTEX DECREASES IMAGE SIZE Farah (2000) experiment, 288
Supporting idea that the visual cortex is important for imagery: Pt with severe epilepsy, M.G.S., was tested before & after removal of right occipital lobe
IMAGERY and the BRAIN ➢ Transcranial Magnetic Stimulation Kosslyn (1999) Experiment:Method TMS, 287
TMS: • Decreases brain functioning in a particular area of the brain for a short time • If behavior is disrupted, the deactivated part of the brain is causing that behavior In response to Pylyshyn's argument that brain activity may be an epiphenomenon just like spatial experience of mental images... Kosslyn (1999) experiment • TMS to visual area of brain during perception and imagery task • Response time slower for both • Brain activity in visual area of brain plays a causal role for both perception and imagery
TEST YOURSELF 10.1 6. How have experiments demonstrated interaction between imagery and perception? What additional evidence is needed to help settle the imagery debate, according to Farah?
The basic rationale behind showing how imagery and perception interact is that if imagery affects perception, or perception affects imagery, this means that imagery and perception both have access to the same mechanisms. The following experiments demonstrated parallels between imagery and perception: (a) size in the visual field (visual walk task); (b) interaction between perception and imagery (Perky's 1910 experiment; Farah's experiment in which subjects imagined H or T); and 9c) physiological experiments. Farah suggested that instead of relying solely on behavioral experiments, we should investigate how the brain responds to visual imagery, since we now have access within neurophysiology--to study patients with brain damage--from electrophysiological measurements. We also have brain imaging as a method.
TEST YOURSELF 10.1 4. Describe the spatial (or depictive) and propositional explanations of the mechanism underlying imagery. How can the propositional explanation interpret the results of Kosslyn's boat and island image-scanning experiments?
The propositional representation is one in which relationships can be represented by abstract symbols, such as an equation, or a statement such as "The cat is under the table.". Spatial representation involves different parts of an image that can be described as corresponding to specific locations in space, for example, this would involve a spatial layout showing the cat and the table that could be represented in a picture. A propositional representation would predict that when starting at the motor; it should take longer to scan and find the anchor than to find the porthole because it is necessary to travel across three links to get to the porthole (dashed line) and four links to get to the anchor (dotted line). This is similar to the semantic networks described in Chapter 9, page 256.
TEST YOURSELF 10.2 4. Under what conditions does imagery improve memory? Describe techniques that use imagery as a tool to improve memory. What is the basic principle that underlies these techniques?
The use of imagery can improve memory in a number of ways: (a) visualizing interacting images; (b) organization using the method of loci; (c) and associating items with nouns using the peg word technique. The basic principle underlying these techniques is: Mental imagery mnemonics underlie most of the powerful mnemonic techniques that have been recommended as practical memory aids for over 2000 years. Forming mental images allows you to link together things which are not otherwise connected, and exploits visual-spatial relationships (Morris & Stevens, 1974). https://thepsychologist.bps.org.uk/volume-19/edition-10/how-toimprove-your-memory
TEST YOURSELF 10.2 3. What are some differences between imagery and perception? What have most psychologists concluded about the connection between imagery and perception?
There is also physiological evidence for differences between imagery and perception. This evidence includes (a) differences in areas of the brain activated and (b) brain damage causing dissociations between perception and imagery. Most psychologist, taking all the above evidence into account, have concluded that imagery is closely related to perception and shares some (but not all) mechanisms.
IMAGERY and the BRAIN ➢ Brain Imaging Sue-Hynn Lee (2012) Experiment, 287
Used Neural Mind Reading ~ Studied brain activation patterns to determine what their subjects were perceiving or imagining ➢ Activity in visual cortex, which respond to small details more obvious when perceiving, was best for perceiving ➢ Activity in higher visual areas, which respond more to whole objects, best for imagining
IMAGERY IN THE HISTORY OF PSYCHOLOGY ➢ Imagery And The Cognitive Revolution Shepard and Meltzer (1971), 278
Used mental chronometry. Important because it was the 1st to apply quantitative methods to the study of imagery and to suggest that imagery & perception may share the same mechanisms.
IMAGERY IN THE HISTORY OF PSYCHOLOGY ➢ Early Ideas About Imagery , 277 Dating back to first laboratory of psychology, founded by Wilhelm Wundt, who proposed that images were one of the three basic elements of consciousness, along with sensations and feelings. (Structuralism)
Wundt proposed that because images accompany thought, studying images was a way of studying thinking--led to the imageless thought debate, the dispute over Wundt's and Aristotle's idea that "Thought is impossible without an image". Arguments for and against idea until the emergence of Behaviorism, when images were deemed "unproven" and "mythological" and therefore not worthy of study.
conceptual peg hypothesis, 278
a hypothesis, associated with Paivio's dual coding theory that states that concrete nouns create images that other words can hang onto, which enhances memory for these words
paired-associate learning, 277
a learning task in which participants are first presented with pairs of words, then one word of each pair is presented and the task is to recall the other word
pegword technique, 292
a method for remembering things in which the things to be remembered are associated with concrete words
method of loci, 291
a method for remembering things in which the things to be remembered are placed at different locations in a mental image of a spatial layout. See also Pegword technique.
epiphenomenon, 280
a phenomenon that accompanies a mechanism but is not actually part of the mechanism. An example is lights that flash on a mainframe computer as it operates
unilateral neglect, 288
a problem caused by brain damage, usually to the right parietal lobe, in which the patient ignores objects in the left half of his or her visual field
mental scanning, 278
a process of mental imagery in which a person scans a mental image in his or her mind
spatial representation, 279
a representation in which different parts of an image can be described as corresponding to specific locations in space. See also Depictive representation.
propositional representation, 280
a representation in which relationships are represented by symbols, as when the words of a language represent objects and the relationships between objects
mental walk task, 282
a task used in imagery experiments in which participants are asked to form a mental image of an object and to imagine that they are walking toward this mental image
imagery neuron, 284
a type of category-specific neuron that is activated by imagery
visual imagery, 276
a type of mental imagery involving vision, in which an image is experienced in the absence of a visual stimulus
IMAGERY and PERCEPTION: DO THEY SHARE the SAME MECHANISMS? ➢ Is There A Way To Resolve The Imagery Debate?, 283-284
a) Can't rule out prepositional explanation b) Can't ignore tacit knowledge explanation just on basis of behavioral experiments c) Farah also suggested investigating how the brain responds to visual imagery using brain imaging and brain damaged individuals
tacit knowledge explanation, 281
an explanation proposed to account for the results of some imagery experiments that states that participants unconsciously use knowledge about the world in making their judgments. This explanation has been used as one of the arguments against describing imagery as a depictive or spatial representation
food craving, 292
an intense desire to eat a specific food
depictive representation, 280
corresponds to spatial representation. So called because a spatial representation can be depicted by a picture
mental chronometry, 278
determining the amount of time needed to carry out a cognitive task
mental imagery, 276
experiencing a sensory impression in the absence of sensory input
imagery debate, 279
the debate about whether imagery is based on spatial mechanisms, such as those involved in perception, or on propositional mechanisms that are related to language
imageless thought debate, 277
the debate about whether thought is possible in the absence of images
IMAGERY and the BRAIN ➢ Brain Imaging Ganis (2004) fMRI Experiment Result, 286
➢ Complete overlap of activation by perception & imagery in front of the brain ➢ Differences near back of brain • More activation from perception, because visual cortex is where signals from the retina first reach the cortex
IMAGERY and the BRAIN ➢ Brain Imaging Amedi (2005) Experiment, 286
➢ Found overlap ➢ Deactivation of non-visual areas of brain • Hearing • Touch ➢ Mental image may be more fragile, less activation keeps other things from interfering
IMAGERY and the BRAIN ➢ Brain Imaging Kosslyn (1995) Experiment, 285
➢ Made use of the way the visual cortex is organized as a topographic map • refers to specific locations on a visual stimulus cause activity at specific locations in the visual cortex and that points next to each other on the stimulus cause activity at locations next to each other on the cortex. ➢ Research suggests looking at: • a small object causes activity in the back of the visual cortex • larger objects causes activity to spread toward the front of the visual cortex ➢ Wondered what would happen if subjects created mental images of different sizes? Found that both imagery and perception result in topographically organized brain activation
IMAGERY and PERCEPTION: DO THEY SHARE the SAME MECHANISMS? ➢ The Imagery Debate: Is Imagery Spatial or Propositional?, 280-281 Finke and Pinker (1982)
➢ Participants judge whether arrow points to dots previously seen ➢ Longer reaction time when greater distance between arrow & dot (as if they were mentally "traveling") ➢ Not instructed to use visual imagery ➢ No time to memorize, no tacit knowledge
IMAGERY and PERCEPTION: DO THEY SHARE the SAME MECHANISMS? ➢ The Imagery Debate: Is Imagery Spatial or Propositional? Current weight of evidence, 282
➢ Two approaches to imagery debate-- spatial and propositional ➢ Pylyshyn's arguments can't be ignored ~ He is in minority ~ led to much research & knowledge about visual imagery ➢ Weight of evidence supports spatial mechanism, which is shared with perception mechanisms
IMAGERY and the BRAIN ➢ Imagery Neurons in the Brain Kreiman (2000) Experiment, 284
➢ found neurons that responded to some objects but not to others ➢ a type of neuron which fires in same way to both image of object and imagining the object--imagery neurons ➢ Important discovery because it demonstrates a possible physiological mechanism for imagery and because these neurons respond in the same way to perceiving an object and to imagining it--thus supporting the idea of a close relation between perception and imagery. ➢ Most research in this area involves large areas of the brain using brain imaging techniques.