PSY 328- Chapter 10 Visual Imagery

mental imagery

Ability to recreate the sensory world in the absence of physical stimuli

Visual Imagery

Seeing in the absence of a visual stimulus

Aphantasia

The inability to voluntarily visualize mental images

Hyperphantasia

Individuals experience exceptionally vivid and detailed mental imagery, often described as being as clear and realistic as real-life perception

Formal Mnemonics

Rely on pre-established sets of memory aids and considerable practice to be effective

Informal mnemonics

Self-invented, typically less elaborate, and are more suited to smaller amounts of information

Method of Loci

A classic mnemonic device in which the to-be-remembered items are mentally placed into a set of pre-memorized locations, with retrieval being a mental walk through locations.

peg-word method

Associate items with a pre-established set of "peg" words

-Link each item on your list to a corresponding pef word through vivid, interactive imagery

Paivio(1963): Gave list of concrete and abstract word pairs

Found: Concrete nouns are easier to imagine than abstract nouns

Paivio(1963): Used Pair Associate Task: present pairs of words and test them by giving them the first word and asking them to recall the second

Found: Better memory for concrete word pairs than abstract word pairs

Conceptual Peg Hypothesis

Hang the images of concrete nouns onto other images of concrete nouns, making them easier to remember(creates better retrieval cues)

Dual Code Hypothesis

Concrete words show a memory advantage because they are coded into memory twice

Kosslyn(1973): Imagery Debate

Argued that imagery involved spatial representation; Believed representation is analogous to the perception

Pylyshyn(1973): Imagery Debate

Argued that imagery was epiphenomenal; believed representation is propositional(using words)

Analog Code

-Images as representations strongly resembling the physical object

-Relating to perception-neural responses of present stimuli preserve the relationships between features of the stimuli

-Details missed during perception will be missing in the internal image

Propositional Code

-Language Like

-Internal images take on abstract representations

-Descriptive(non-featural) representations

Mental Rotation

If an internal image resembles the physical object, then judgments about the internal image should resemble judgments of the physical object

Shepard and Metzler(1971): Used mental chronometry to measure how long mental processes take, asked if objects were the same or different rotated

Found: As the degree of rotation increases, reaction time increases

-Analog Code

Mental Scanning

Forming a mental image and then scanning it

Kosslyn(1973;1978): Study image and learn locations-Form mental image of island-Ask subjects to travel from one point to another

Found: The longer the spatial distance between points, the greater the reaction time for mental scanning.

Pylyshyn(1973)

Representation is a network of words; the mental picture we experience is a result of the verbal information stored in memory(epiphenomenal)

Roy G BIV is a specific type of mnemonic device called an ________?

Acronym

T/F: Kosslyn would say that if you were shown the following image and then asked to recall it, it would actually be represented as abstract statements like: Asleep [Action] (Garfield [agent of action], Pan [Object])?

False->Pylyshyn

________is the measure of how long mental processes take, as is often used in perceptual motor tasks?

Mental Chronometry

Which mnemonic device is used when the to-be-remembered items are mentally placed into a set of pre-memorized locations?

Method of Loci

Kosslyn(1978): Asked participants to imagine a rabbit and elephant; rabbit and fly, such that the larger animal takes up most of the visual field

Found: When the rabbit takes up the larger portion of the visual field in the mental image, it is easier to see more distinct details

-Suggests that mental imagery is like perception

Perky(1910): Asked participants to imagine an object like a banana and describe the mental image they see while looking at a "blank" screen

Results: The description of the mental image mirrors the banana presented on the screen

-Participants mistake the presented image for the mental image

-Suggests that percepts and imagery use similar neural mechanism

Chambers and Reisberg(1985): Presented ambiguous figures and asked to draw the figure from memory; then asked to reinterpret the image they have drawn

Found: Most participants cannot reinterpret the image they have drawn

-Suggest that propositional code can dominate over an analog code

-May use both analog and propositional coding for mental imagery

Kreiman(2000): Examined single neuron recordings in humans; electrodes were implanted to detect where epileptic seizures were occurring

Group 1: Showed faces and objects

Group 2: Asked to imagine faces and objects

Found:

-Perceive an Object = Neural Firing

-Perceive a face = No Neural Firing

-The same occurred for imagined images and objects

LeBihan(1993): Placed Participants in fMRI and measured brain activity

-without any stimulation

-Activity in visual cortex when stimulus present(Perception)

-Activity in visual cortex when imagining(imagery)

Found: The visual cortex is activated during both perception and imagery

Ganis(2004): Examined the commonalities between perception and imagery by looking specifically at which brain regions overlap

Found

-Frontal and Parietal Lobe: No difference

-Occipital Lobe: More activation for perception than imagery

--Suggests almost complete overlap BUT this doesn't prove activation causes imagery

M.G.S: Suffered Severe epileptic seizures and had a portion of her visual cortex removed: Mental Walk Task before and after surgery Results...

Pre-Surgery: Imaged that she got within 15 feet of the horse before it overflow

Post Surgery: Imaged the horse starts to overflow at 35 feet

R.M.: Experienced damage to the occipital and parietal lobe

He can recognize and draw objects placed in front of him BUT cannot draw objects from memory or answer questions that require imagery

C.K: Suffered from apperceptive agnosia-cannot visually recognize objects

He can detect features of an object but not identify it as a whole;he can imagine and draw the image from memory, but would not be able to recognize his own drawing after forgetting the task

Behrmann(1994) Perception and Imagery partially overlap

The perception involves lower and higher visual centers

-Bottom Up processing

-Info sent to high visual centers to assembe(Top Down)

Imagery involves mainly higher-level visual centers

-Top-Down processing: imagery starts at higher levels responsible for memory; images are "preassembled" and do not require activation from the visual cortex

Neuropsychological evidence, such as the case study of M.G.S. who had part of her visual cortex removed, suggested what about imagery and perception?

The visual cortex is also important for imagery

T/F: In the Chambers & Reisberg (1985) study, participants were typically able to reinterpret a drawn figure from an ambiguous image after viewing the original figure?

False

There is about 70% - 90% overlap in cortical activations between perception and imagery, but researchers speculate that imagery uses more _____ processing and perception involves more _____ processing.

-Imagery=top-down

-Perception=mixed