Visual Imagery

Aristotle's idea of thinking and imagery

"thought is impossible without an image"

Francis Galton

1883 Evidence supporting imagery is not necessary for thinking Observed people who had a lot of trouble forming visual images but were very capable of thinking

Imagery's resurgence

1950's due to the cognitive revolution ways to measure behavior that could be used to infer 'unseen' cognitive processes

Alan Paivio

1963 part of the cognitive revolution Work on memory easier to remember concrete nouns that can be imaged over abstract nouns that don't have a definitive image paired-associate learning

Roger Shepard and J. Metzler

1971 inferred cognitive process by using mental chronometry gave subjects two objects which were oriented differently, asked participants to determine whether they were the same shape or not as quickly as possible. One of first studies to quantify studies of imagery and suggested similar mechanisms between imagery and perception

G. Lea

1975 proposed a different explanation--> as participants scanned they encountered other parts of the boats on the way which served as a distractor, increasing the reaction time

Koslyn Visual Field Experiment

1978 asked participants to visualize two animals next to each other (ex elephant and a rabbit) and that they were standing close to each other so the larger one took up most of the visual field they were asked a question about the rabbit (does it have whiskers) this was compared to when they were told visualize two animals such that the rabbit was the animal taking up the larger portion of the visual field (rabbit and fly). Participants were able to answer the question quicker when the rabbit was the image taking up the larger part of the visual field Also asked them to do a Mental Walk Task

E. Bisiach and G Luzzatti

1978 tested the imagery of a patient with unilateral neglect asked him to describe things he saw while imagining himself at the Piazza del Duomo in Milan, a familiar place to the patient prior to suffering the brain damage The patient neglected the left side of his mental image similar to the neglect observed in the left side of his perceptions supports the shared mechanisms of mental imagery and perception

Finke and Pinker results

1982 the further the arrow was from any of the dots the longer it took for them to respond they weren't given enough time to form/use tacit knowledge thus supporting the spatial representation

Ronal Finke and Stephen Pinker

1982-->sought to counter to tacit knowledge explanation briefly presented a four dot display, after a 2 second delay presented an arrow (no dots presented) participants asked to indicate whether the arrow was pointing to any of the dots that were briefly shown before

Deborah Chalmers and Daniel Reisberg

1985 experiment on difficulty of manipulating imagery over perception participants asked to crete mental images of ambiguous figures which can be seen as a rabbit or a duck perceptually--> easy to flip between these two perceptions imagery--> participants holding the mental image of the ambiguous figure were unable to flip between the perceptions

Martha Farah

1985, replicated Perky's experiment instructed participants to imagine either the letter "H" or "T" on a screen. Once clear images were formed they were asked to press a button that caused two squares to flash one after the other. One had the target letter (H or T) task--> indicate if the letter was on the first or the second square results--> target letter was detected more accurately when the participant had been imagining the same letter rather than a different one. showed perception and imagery share mechanisms

Ronald Finke

1989 asked participants to imagine a capital "D" and then to place a captial "J" under, they reported seeing an umbrella

Mary Haggerty

1992 when asked to solve the pulley-problem participants took longer to establish direction of the lower pulley than the upper pulley participants first determined direction of upper pulley and how that would effect the second pulley, and so on. considered how each individual component in the sequence to determine effect on the later componenets

LeBihan and coworkers

1993 early brain experiment on imagery, demonstrated both perception and imagery activate the visual cortex-->measured activation during both perceiving an object and imagining an object in the striate cortex in comparison to baseline conditions asked participants questions that involved imagery and ones that didn't (measuring brain activation)

C. Guariglia

1993 studied a patient whose brain damage had little effect on ability to perceive but cause neglect in mental images, this served as a basis for dissociations between mechanisms of perception and imagery.

Daniel Schwartz and Tamara Black

1999 proposed water pouring problem without giving them time to either reason out the problem or to use mental imagery, most answered incorrectly saying that both will pour at the same tilt however, when they asked participants to imagine the glasses being tilted, most were able to "see" that the narrower glass would have to be tilted further relevant to tacit knowledge found people tend to use mental simulation before shifting to using rules

Friedrich August Kekule

19th century German Chemist structure of benzene came to him in a dream where he remembered a snake eating its own tail-->shape of a ring

Fred Mast and Kosslyn

2002 Showed that people who were good at imagery were able to rotate mental images of ambiguous figures if they were provided with extra information (parts of the images that are partially rotated)

Giorgio Ganis

2004 observed differences between areas activated by perception and by imagery used fMRI to measure activation under perception and imagery conditions perception-->participants observed a drawing of an object imagery--> participants asked to imagine a picture they had studied before when presented with a tone For both conditions participants were asked to answer a question (is the object wider than it is tall?) results--> almost a complete overlap in activation near the front of the brain but some differences are noted in the back of the brain (regions connected to vision)

Amir Amedi

2005 fMRI experiment showed overlap between activation under perception and imagery but also showed when imaging a picture, deactivation of areas associated with non visual senses (hearing and touch) occurred Suggested that visual mental images are more fragile than actual perception, deactivation quiets down irrelevant activity that could interfere with mental imagery

Pegword technique

A method for remembering things in which the things to be remembered are associated with concrete words. often the basis behind books claiming to provide a key to improving memory --> requires a great deal of practice and perseverance

R.M.

Case study of normal perception but impaired imagery, suffered damage to occipital and parietal lobes was able to recognize and draw objects accurately if they were placed in front of him but was unable to draw such objects from memory (requires imagery) also had trouble answering questions that depends on imagery

C.K.

Case study, 33 year old graduate student struck by a car while he was jogging. Perception was impaired but mental imagery was relatively normal. Suffered from visual agnosia

Making sense of neurophysiological results

Cases can present a paradox, show close parallels in perceptual and imagery deficits but also present a number of cases where dissociations occur

Cheves Perky

Classic demonstration of interaction between perception and imagery (1910) asked participants to project visual images of common objects onto a screen and then to describe these images while projecting a dim image of this object onto the screen they were looking at, unknown to the participant. The images they were describing matched the images that Perky was back-projecting onto the screen (orientation) none noticed the presence of the back-projection

Depictive representations

Corresponds to spatial representation. So called because a spatial representation can be depicted by a picture. Like realistic pictures that resemble an object

Jack Nicklaus Mental Imagery

Discovered an error in his swing relating to the way he gripped the club as he was practicing his swing in a dream

Simonides

Greek Poet 2,500 years ago presented an address at a banquet, after he gave the speech the roof collapsed killing most of the people and mutilating them beyond identification. Simonides had created a mental picture of where everyone was during his speech and was able to determine who had been killed based on their location. Method of Loci

Albert Einstein's Mental Imagery

Helped develop the theory of relativity by imagining himself traveling beside a beam of light

Wilhelm Wundt

History of mental imagery can be traced back to his psychology lab proposed that images were one of the three basic elements of consciousness (other 2--> sensations and feelings)

Neurophysiological Case Studies

How brain damage can affect imagery, as well as how affects both imagery and perception and if so, in the same way?

Size in the visual field

Imagery is affected by the size of an object in a person's visual field the closer something is the more of the visual field it occupies and the easier it is to perceive details compared to seeing the same object from afar.

Inner audition

Imagining a sound in your mind. Ex: conducters imagine musical scores in their minds

Mental Walk Task

Kosslyn asked participants to imagine they were walking towards their mental image of an animal task-->estimate how far away they were were from the animal when they began to experience "overflow" result-->participants had to move closer for small animals compared to large animals provides evidence that images are in fact spatial within the mind

Spatial Representation

Kosslyn interpreted his results to support this idea proposed by him representation in which parts of an image can be described as pertaining to specific spatial locations

Paired-associate learning

Learning procedure in which items to be recalled are learned in pairs. During recall, one member of the pair is presented and the other is to be recalled

Conclusions from the Imagery Debate

Most psychologists agree that imagery and perception are closely related and share some, but not all, mechanisms

Conceptual peg hypothesis

Paivio concrete nouns create images that words can "hang onto," providing a number of places on which they can recall the paired word in their mind

Martha Farah 1993

Performed the Mental Walk Task on M.G.S before the operation. Before she stated that she was about 15 feet before the image overflowed, after the operation the distance changed to 35 feet. Removing the right occipital cortex (part of the visual cortex) reduced the size of her visual field-->horse filled up the view from further away Visual cortex is important for imagery

Stephen Kosslyn

Prominent imagery psychologist

Imagery Neurons

Proposed by Kreiman They respond to both perceiving and imagining an object, they fire in response to specific objects

Tacit knowledge explanation

Proposed by Pylyshyn stating that participants unconsciously use knowledge about the world in making their assumptions (in this case of what an image is supposed to look like)

Propositional representation

Pylyshyn proposed this as the mechanism underlying imagery in which relationships can be represented by abstract symbols (ex. equation or statement)

Kosslyn 1978

Response to G.Lea's proposition asked participants to scan between two places on a map told to imagine an island with seven different locations and to mentally scan between ever possible paired trip (meaning a total number of 21 trips) relationship between reaction time and distance shown -->took longer to scan between greater distances on the image

Mental Scanning

Stephen Kossyln tested the idea that there is a spatial correspondence between imagery and perception

Marlene Behrmann

Studied C.K. he was able to recognize parts of an object when presented an image but could not group them into a meaningful whole to identify the actual object he was however able to draw objects from memory in detail--> depends on imagery when shown his own drawings after sometime, he couldn't identify them though

Shepard and Metzler 1971 Results

The time it took for participants to recognize if they were the same shape correlated to how different the angles of the shapes were in the two views participants were mentally rotating the images of one to determine a match

Perceptual problems project onto imagery

a person who has trouble perceiving colors will have the same problem when creating colors in imagery

Mental Imagery

ability to recreate the sensory environment in the absence of any physical stimuli occurs with senses other than vision provides a way of thinking that adds another dimension to the verbal processes associated with thinking

Pylyshyn and Brain Activity

argued that just as spatial experience could be an epiphenomenon, brain activity could be also. Something is happening but may have nothing to do with causing the imagery

Brain Imaging

brain activity was often measured using either PET of fMRI as participants were creating visual images vs baseline conditions where they were not

Marlene Behrmann 1994

came up with one way of explaining the paradox mechanisms of perception and imagery do overlap but only partially mechanisms for perception--> located in higher visual centers. Visual perception involves bottom-up processing mechanisms for imagery-->involves top down process, in the higher brain areas responsible for memory, they do not depend on activation of cortical areas like the visual cortex

Unilateral Neglect

condition stemming from damage to the parietal lobes patients ignores objects in one half of the visual field

C.K.'s case hypothesis

couldn't perceive objects well therefore his damage is caused by impaired functions early in the processing stream, but could still create images because higher level areas were unaffected

Imagery debate

debate whether imagery is based on spatial mechanisms (such as those in perception) or based on mechanisms related to language

John Watson and Imagery

described images as "unproven" and "mythological", therefore not worthy of study

mental chronometry

determining the time needed to carry out a number of cognitive tasks

Kosslyn 1973

early experiment asked participants to memorize a picture of an object (ex. boat) then to create an image of that object in their mins and to focus on one part of that image (ex. anchor) Then asked to look for another part of the boat and asked to answer true when they found the part and false when they couldn't find the part reasoned that if imagery was like perception then it would take longer for the participants to find parts located further from the initial point (actually what happened)-->evidence for spatial nature of imagery

Behaviorism and Imagery

ended the arguments and counterarguments surrounding imagery John Watson-->founder of behaviorism labeled the study of imagery as unproductive because it was not an observable facet except to the person experiencing it

Propositional approach to Kosslyn's Boat experiment

figure 10.6 Words indicate parts of the boat; length of the lines indicate distances between parts; words in parentheses indicate spatial relations between the parts This approach is also supported by the reaction time and spatial distance noted in Kosslyn's experiment Proposes that imagery works similarly to a semantic network

R.M.'s case hypothesis

had difficulty creating mental images, therefore his damage was caused by impaired functioning in the higher level areas but the earlier processes were unaffected allowing him to perceive relatively normally

Imageless thought debate

idea of a link between thinking and imagery gave rise to the debate Some psychologists backed aristotle's idea and others said thinking can occur without images

the five gear problem

if each of the gears meshes with the next one, and gear 1 is turning clockwise, in what direction will gear 5 turn

Interactions of imagery and perception

if imagery affects perception of perception affects imagery it means that imagery and perception both have access to the same mechanisms

pulley problem

if you pull on the free end of the rope at the arrow, will the lower pulley turn clockwise? figure 10.23

Imagery vs Perception

may share the main mechanisms but images are not as vivid or as long lasting, but they do share many common properties

Propositional mechanisms

mechanisms related to language

Method of Loci

method in which things to be remembered are placed in different spatial locations in a mental image of a spatial layout. Method that Simonides used to determine who had been killed Placing images at locations can help with retrieving memories at a later time

rule based approach

method of solving mechanical system problems applying a rule which is previously known (all odd numbered gears will turn in the exact same direction or the next gear will turn in the opposite direction of the previous one) tied to the idea of propositional representation

Mental Simulation

method of solving mechanical system problems the operation of the mechanical system is mentally represented tied to the idea of spatial representation

Imagery to improve memory

organization improves encoding, imagery has the ability to create organized locations for memories of specific items to be placed in.

Differences in imagery and perception properties

perception occurs automatically, imagery requires some effort perception is stable, happening as long as the stimulus is present while imagery is fragile, can disappear without continued effort harder to manipulate mental images than images created perceptually

Martha Farah Imagery Debate

pointed out that it is difficult to reject Pylyshyn's tacit knowledge explanation solely on the basis of behavioral experiments participants can always be influenced by past experiences of perception, Mental walk task could yield results due to previous experiences with animals and not a spatial image in their mind proposed investigation of how the brain responds to visual imagery on top of just behavioral experiments

Physiological evidence for perception:imagery relationship

points to a connection but the overlap is not perfect

Kossyln 1999

presented TSM to the visual area of the brain while participants were performing a perception or imagery task. perception task--> briefly viewed a display (fig 10.16) and were asked to make judgment about the stripes in two of the quadrants (were the stripes in quadrant 3 longer than those in quadrant 2?) imagery task--> same task expect participants were asked to make the judgements off of closing their eyes and forming a mental image of the display measured based on reaction time between TSM and non-TSM conditions results-->TSM caused participants to respond more slowly, this effect applied to both perception and imagery tasks--> activation in fact is not an epiphenomenon

Zenon Pylyshyn

proposed another explanation to Kosslyn's theory of the spatial nature of imagery (1973) sparked what has been called the imagery debate proposed that even though we may experience imagery as spatial it doesn mean that the underlying representation is spatial epiphenomenon Proposed a propositional representation

Epiphenomenon

something that accompanies the real mechanism but is not actually part of the mechanism Described by Pylyshyn as pertaining to the spatial experience of mental images. Mental images indicate something is happening in the mind but don't tell us how it is happening example--> lights flashing as a computer is calculating/processing a task

Double dissociation of perception and imagery

stems from cases where the two are affected differently in the case of brain damage interpreted to mean that the two functions are served by different mechanisms

Gabriel Kreiman

studied patients who had electrodes placed in various areas of the medial temporal lobe to determine the source of sever epileptic seizures uncontrollable by medication found--> some neurons respond to some object but not others (baseball but not a face) it also fires when they imagine a baseball and doesn't when they imagine a face

Transcranial Magnetic Stimulation (TMS)

technique used by Kosslyn (1999) in an experiment to disprove Pylyshyn's statement regarding the epiphenomenon of brain activity in imagery. Applying a pulsating magnetic field to the skull to temporarily disrupt the functioning of a specific brain region, participants behaviors is tested while the brain area is deactivated. If the behavior is disrupted it can be concluded that the area deactivated is the causal factor of said behavior

water pouring problem

two glasses are the same height and are filled to the same level. when these two glasses are tilted, will the water begin pouring out of the glasses at the same tilt or at a different tilt, if different, which will pour first?

M.G.S.'s case hypothesis

unable to be explained under the same conditions of C.K. and R.M. even though her damage was located earlier in the processing, both perception and imagery were affected

John Anderson Imagery Debate

warned that despite overwhelming evidence of a spatial representation in imagery, we cannot rule out the propositional explanation

Overflow in Mental Walk Task

when the image filled the visual field or when its edges started becoming fuzzy

Patient M.G.S.

young woman who was about to have part of her right occipital love removed due to severe epilepsy