Lecture 15 - Imagery

What is imagery?

• internally constructing a memory representation that preserves visual and spatial information

• processing of perceptual-like information in the absence of external perceptual stimuli

• visualizing something using your "mind's eye"

What is Auditory Imagery?

Imagine a dog barking

What is smell imagery?

Imagine a bad fart in a car with the windows closed

What are the three principles of visual imagery?

- Implicit (incidental) encoding

- Perceptual equivalence

- Spatial equivalence

What is Implicit (incidental) encoding for visual imagery?

- unintentional storage of detail

- often never accessed

What is perceptual equivalence?

to what extent are perceptual details part of a visual

image?

What is spatial equivalence?

- To what extent are spatial relations part of an image?

- e.g., "Is there a lamp to the left of the couch as you're facing the window

What are the 4 pieces of evidence that imagery is like perception?

• Interference

• Manipulation

• Pictorial Properties

• Imaging (fMRI)

What is interference?

• If perception & imagery overlap in function (& brain areas), they should interfere with one another

What did Segal & Fusella (1970) find about interference?

- Form a visual (a tree or table) or an auditory image (a dog barking or car horn), or no image

- Then participants detected faint signals

- auditory: faint harmonica cord

- visual: small blue arrow

What did Rogar Shepard look at for image manipulation?

• Mental Rotation

- verification from memory

- mental images can be "rotated" just like real objects

- Is the letter forward or backward?

- The more that you need to rotate the object, the longer it takes

akin to rotating a page on which each letter was on

What is mental rotation?

The process of continuously transforming the orientation of a mental image

What did Shepard & Metzler (1971) find for visual imagery?

• among the first to study the functional properties of mental images

• mental processing analogous to physical action

What do mental Images have?

picture-like properties

- scanning an image (Stephen Kosslyn)

- zooming in on an image

- feature verification using a produced image vs. other types of knowledge

What is zooming in?

imagine 2 things next to one another (at the same time)

1. a mouse & an elephant

"Does the mouse have whiskers?"

2. a mouse & a paperclip

"Does the mouse have whiskers?"

Participants faster in (2) than in (1)

What is feature verification?

Feature Verification

• "Imagine a cat" vs. "think about the features of a cat"

• Think about the features of an object or animal

- faster to respond to highly associated features (physical parts)

- for cats: "has claws" faster than "has a head"

• Produce an image

- faster to respond to features that take up the largest area on a person's image

- for cats: "has a head" faster than "has claws

Are images like perception?

- real visual stimuli must be interpreted

- images are already interpreted when they are constructed

- people don't seem to re-interpret their own images

What is Neural Overlap?

• participants view pictures of faces and places (houses, fields, rivers)

• visualize (imagine) faces and places

• visual perception experiments

- fusiform face area (FFA) more active for faces than for places

- parahippocampal place area (PPA) more active for places than for faces

What is aphantasia?

people who report a lack of conscious (deliberate) imagery

What is the percentage of people who have aphantasia?

- ~ 4% of the population

- mostly visual imagery, but other types as well

- 21% report dreaming without images

- 8% report not dreaming at all

- of non-aphantasics, 6% say they dream without images, & < 1% say they don't dream at al

What did barsolu say about aphantasia?

perceptual simulations

- people simulate objects & scenes during language comprehension

- viewed as implicit, automatic processing

• Aphantasics report no deliberate image production

What did aphantasia and simulation Speed, Geraerds, & McRae (2025) do?

• feature verification

- Is it a physical part? bicycle - handlebars

• manipulated "no" trials

- easy: car - tail (completely unrelated)

- hard: monkey - banana (related, but not a part)

• Aphantasics: same differences between easy & hard trials as non-aphantasic participants

• Implicit simulation, but no deliberate imagery

What did Laura Speed say about Aphantasia & Simulation?

• Aphantasics read "normally"

• participantsread fictional stories

• report not "getting into" or "being absorbed in" a fictional story (as compared to non-aphantasics)