cognitive psych- chap 10 (imagery)

visual imagery

"seeing" in the absence of a visual stimuli ex: if you had 5 large suitcases how would you arrange them in the trunk of your car ?

resolving imagery debate

- still hard to rule out the propositional explanation .. it is likely that visual imagery utilized bot (spatial and propositional)

The imagery debate (spatial or propositional)

- this refers to two differing view points discussing the exact nature of (visual) images . 1) Spatial (Analog) viewpoint: Kosslyn - visual mental images are comparable to pictures in your head 2) Propositional viewpoint: - although we experience images as pictures, they are stored as non pictorial abstract concepts (equations, statements)

mental scanning experiement

1) p's 1st create mental images and then scan them in their minds (in this case it was a boat) 2) asked to only focus on the "anchor" of the boat 3) then asked to "scan" the mental image and to focus on the motor (which is on the other side of the boat) results: since imagery, like perception, has a spatial compnent it takes longer for p's to find parts (motor) that are located farther than the intial focus (anchor)

paired-associate learning (Alan Palvio)

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. experiment results: - easier to remember concrete nouns (e.g tree, book, pen) - harder to remember abstract nouns (e.g beauty, truth, justice)

double dissociations (case study)

- brain damaged paitent - paitents perception intact, but mental images were impaired (unilateral negelct in imagination_

Mental imagery

- can be imaginative - our ability to re-create a sensory world in the absence of a physical world (includes all senses)

Farah (1985) - Priming experiement

- can imagining a visual representation of a stimuli prime the perception of a real visual stimuli 1) p'ss were asked to mentally imagine either the letter "H" or "T" 2) were then either shown two squares , one after the other, that either contained the letter "h" or "t" task: indicate whether the letter was in the 1st square or 2nd square results: target letter was detected more accurately when the participant had been imagining the same letter as their target letter (mental image primes the perception of the target)

Paitent R.M

- damage to occipital and pariteal lobe - could draw accurate pictured of objects in front of him (perception) - could not draw accurate pictured of objects from memory (imagery)

transcranial magnetic stimulation (TMS)

- decreases brain functioning in a paticular area of the brain for a short time .. without lesion to the brain - if behavior is disrupted the deactivated part of the brain is causing that behavior

Imagery in the brain, and perception (Garis and coworkers)

- determine whether there is an overlap between brain areas activated by perception or imagery - used fmri to measure activation under two conditions : 1) perception: p's observed a drawing of an object 2) imagine: p's imagined pictures (one that they had studied before) task: was asked " is the object wider than it is tall" results: - perception and imagery both activate the same areas in the frontal lobe (overlap of activation in front of brain). - perception activates visual cortex more (occipital lobe) than imagery

paitent mgs

- epilietic : was going to have her right occipital . lobe removed -- before the operation, Farah has MGS perform a mental walk task (in which she imagined walking towards an animal and estimated how close sshe was when the image began to overflow) results: 1) Before surgery: felt she was 15 ft from the horse before image overflowed 2) after surgery: horse overflowed at an imagined distance of 35 ft - removing part of the visual cortex reduced size of field of view

mental imagery (usefulness and ability)

- evoking strong mental image= better memory useful: provides an additional dimension to verbal thought processes

Paitent c.k

- his injury blocks the bottom up input for object perception results: - inability to name pictures of objects , even his own drawings - could draw objects in great detail from using imagery

mental walk task

- imagine a mental image , imagine walking towards it. task is to estimate how far you are to the image until it filled up your visual field \ results: people mentally moved closer to the small animals than to the larger animals (just like you would in real life) 1) evidence that mental images are spatially represented, like perception 2) also supports tactic knowledge

Interactions of imagery and perception (Perky 1910)

- participants mistake an actual picture for a mental image results: shows that imagery and perception have access to same mechanisms

using imagery to improve memory

- placing images at locations (methof of loci) Method of loci: - associating words with space - visualizing items to be remembered in different locations in a mental image of a spatial layout

Pylyshyn (Spatial representation)

- spatial rep is an epiphenomenon for mental imagery epiphenomenon : - something that accompanies the real mechanism but is not actually part of the mechanism

Two approaches to mental imagery:

1) Intuitive: - the experience of "seeing" with the minds eye 2) Theoretical: - a cognitive representation that gives rise to the EXPERIENCE OF PERCEPTION in the absence of the appropriate sensory input

imagery and perception ? : may share the same mechanisms.

1) both involve spatial respresentation of a stimuli 2) mental scanning: a process of mental imagery in which a person scas a mental image for items

comparing (relationships) imagery and perception

As you move closer to objects in the real world: - objects fills more of your visual field - details are easier to see 1) A relationship between viewing distance and ability to perceive details

Is imagery spatial or propositional (experiment)

Finke and Pinker: task= judge whether arrow points to any dot you saw (the dots went away before the arrow was shown) - NOT INSTRUCTED to use visual imagery - no time to memorize, no tactic knowledge results: longer reaction time when there was a greater distance between arrow and dot, as is the p's were mentally time traveling - shows imagery is served by a spatial mechanism

Brain activation of imagery and perception (experiement)

Le brain et all - asked participants imagery questions (" are leaves on the trees darker than grass") and non imagery questions (what is the definition of density) - wanted to demonstrate that both perception and imagery activate the visual cortex results: - there is an overlap in brain activation of both perception and imagery - activity in the striate visual cortex increased both perception and imagery

Kosslyn and coworkers (1999)

TMS to visual area of brain during perception and imagery task Brain activity in visual area of brain plays a causal role for both perception and imagery results: - ppl were unable to imagine when visual cortex functioning was disrupted - brain activation is not epiphenomena (it is actually part of the mechanisms)

spatial representation

a representation in which different parts of an image can be described as corresponding to specific locations in space

imageless thought debate (Aristole, Galton/ Watson)

are images necessary for thought?? 1) Aristotle : Yes - imagery is a basic element of consciousness 2) Galton/ Watson: No - imagery is unprovable and mythological - Behaviorism squashes the study of mental imagery

unilateral neglect/ Bisach and Luzati

definition: damage of pariteal lobe can cause patients to ignore objects in one half of the visual field

double dissociation in perception and imagery

fusiform face area: specialized for faces ppa: specialized for representing location (place) info -- subjects either view or imagine a face or place results: FFA includes more signal change in perception than imagery, while ppa has almost an equal balance in both

mental chronometry / Shepard and Meltzer expeirment

mental chronometry: - determining the amount of time needed to carry out a cognitive task experiment: - p's saw pictures and had to indicate as fast as possible whether the two pictures were of the same object or different objects results; rt it took to determine if the two objects were the same was directly related to how different the angles between the two stimuli were (participants were mentally rotating the object)

imagery neurons

neurons that respond to both perceiving and imagining the same stimuli

what is imagery?

sensation without perception ex: - reading poetry - picturing something sing in our heads

conceptual peg hypothesis

that states that concrete nouns create images that other words can hang onto, which enhances memory for these words. ex: presenting the pair "boat- hat" creates an image of a boat, then presenting the word boat later will bring back the boat image, which also provides a number of places/ connections with the other word "hat"

Tacit knowledge explanantion

unconscious use of pre existing knowledge - supports kosslyn's spatial imagery results , as it can be determined by using real-world knowledge unconsciously