psyc2007 lec 9- imagery

What is the fundamental question that visual imagery research tries to answer?

How is visual information stored and represented in our minds when we are not directly perceiving it? is it like a picture or like a description?

Whatt was the key finding of the Shepard and Metzler’s (1971) mental rotation experiment?

Reaction Time increased linearly with the angle of rotation between two 3D objects. The more you had to mentally rotate an object to compare it, the longer it took.

What does the mental orientation finding imply about the nature of visual imagery?

It suggests imagery is quasi-spatial or depictive. We manipulate mental images in a way that preserves their physical, analog properties (like rotation speed), similar to manipulating a real object.

What are the two opposing theories in the "Imagery Debate"?

1. Depictive (pictorial) theory- Mental images are like internal pictures with spatial properties

2. Propositional (descriptive) theory- Mental images are stores like abstract, language like descriptions of relationships (e.g the cat is under the table)

What did Kosslyn’s (1973) image scanning experiment demonstrate?

Participants took longer to mentally "scan" between two points on a remembered image if the points were farther apart. This distance effect supports the depictive theory—mental images seem to have metric spatial properties.

What was Lea’s (1975) criticism of Kosslyn’s scanning study?

he argued the effect might not be duce to distance, but due to the number of items between scan points. he found an “item effect” without a distance effect using a list of campus buildings, supporting a propositional account/

How did Kosslyn, Ball, & Reiser (1978) address Lea's criticism?

They used a map-learning task where all possible point pairs were tested, controlling for items. They still found a strong linear relationship between Reaction time and actual map distance, strengthening the depictive account.

What does neuroimaging (fMRI, PET) show about the brain during visual imagery?

The primary visual cortex (V1) is activated during visual imagery tasks, suggesting overlap in the brain regions used for seeing and for imagining.

How did Kosslyn et al. (1999) test if V1 activation is necessary for imagery (not just correlated)?

They used Transcranial magnetic stimulation (TMS). They applied TMS to disrupt V1 while participants perform a visual imagery task (comparing properties from memory) and a control perception task. 

What was the result and key implication of the TMS study?

Result: TMS to V1 slowed reaction times on both the imagery AND perception tasks compared to sham TMS.
Implication: V1 is functionally involved in generating visual imagery, not just passively activated. Strong support for the depictive theory.

What did Kreiman, Koch, & Fried (2000) discover in the Medial Temporal Lobe (MTL)?

They found single neurons that fired both when a person saw a specific object (e.g sydney opera house) and when they imagined the same object. These are called “imagery neurons”

Why is the discovery of imagery neurons so important for the imagery debate?

t provides direct neurophysiological evidence that perception and imagery share neural machinery at a very specific level (individual neurons), powerfully supporting the idea that imagery is a depictive, perception-like process.

What is a major practical application of visual imagery?

The Method of Loci (Memory Palace): A powerful mnemonic technique where you visualize placing items to remember along a familiar spatial route. Its effectiveness relies on the brain's strong ability to encode and recall spatial/visual information.

What is the modern consensus from imagery research?

The evidence strongly favors the depictive account. Our brain represents and manipulates mental images in a spatial, analog format that shares core properties and neural substrates with visual perception, though some abstract/propositional coding may also exist.