Mental imagery Flashcards
Imagery and Perception: explain Kosslyn (1973) - Boat and Kosslyn (1978) - Island
- Asked participants to memorize a boat
- asked participants to focus on one part of the boat and then mentally move to another.
- Results: increased RT when they had to scan for larger distances.
- Told participants to imagine and island with 7 locations
- There were no distractors
- Obtained the same results as in the first experiment –> increased RT for increased distances
Explain Kosslyn (1978) - Animals
- Imagine 2 animals. 1 small and 1 big.
- Zoom in until the larger animal fills the visual field.
- Asked participants to answer questions about the same animal when it was larger in comparison to the other animal and when it was smaller in comparison to the other animal.
- Participants answered better when the animal was big.
- “Mental walk” –> walk closer to the animal to look at the details –> decreased RT when you are closer
What is the imagery debate?
Is imagery spatial or propositional?
- Spatial
- Propositional –> knowledge of how things relate to each other –> Pylyshyn (1973) –> we use abstract knowledge to answer questions. He didn’t say that visual imagery doesn’t exist but that it is not the cause.
Explain Perky (1910) - projection
- Projected faint images, participants imagined the same objects
- Participants didn’t know that projected images were there
Actual images and visual stimuli seem confusable/similar
Explain Farah (1985) - H or T
- Participants imagined an H or a T
- Then they got an H or a T
- They were more accuarte in detecting the correct letter if both matched
What are the differences between perception and imagery?
- Perception is automatic and stable
- Imagery is effortful and fragile
Chalmers and Reisberg (1985)
- Participants created mental images of ambiguous figures
- Result: Harder to ‘flip’ imaged vs perceived ambiguous figures
What is the relationship between imagery and the brain?
Kreiman et al (2000)
- found that there are individual neurons that activate when you see or imagine a specific stimulus.
Le Bihan et al (1993) - fMRI study
- Real and imagined stimuli activate the same brain areas
Ganis et al (2004) - fMRI
- Found differences between perception and mental imagery
- Similar activations for the front of the brain but not for the back (occipital lobe)
- The visual cortex is in the occipital lobe, and there was more activation of it with visual stimuli than with imagined
Amedi et al (2005) - fMRI
- Similar activation for imagined and perceived
- Imagined activated more areas of the brain –> because it’s more difficult to imagine?
Explain Kosslyn (1999) - TMS
- Used TMS (transcranial magnetic stimulation) to deactivate visual areas of the brain
- This impaired perception and imagery task
- When unrelated areas were deactivated there was no impairment in tasks
- They established a causal relationship
How do perception and imagery relate to top down and bottom up proceses?
Behrmann et al
- Conflicted evidence of overlap between imagery and visual perception.
- Visual perception –> lower visual processing (bottom-up)
- Mental imagery –> top-down process; uses higher visual areas.
- Use to explain some cases. CK lower visual damage –> problems with visual perception
RM higher level damage –> problems with mental imagery
What is mental imagery?
Experiencing a sensory impression without sensory input. It can come in many different modalities (taste, hearing, etc)
What is visual imagery?
- It’s the most commonly researched form of mental imagery.
- Seeing in the absence of a visual stimulus.
- A form of cognition
- Important for creative breakthroughs (e.g., Kekule and the structure of benzene or Einstein and the theory of relativity)
What were Wundt’s early ideas about imagery?
- 3 basic elements of consciousness: sensations, feelings, and images.
Explain the imageless thought debate.
Aristotle claimed that there could be no thought without images. –> though = label for images
Galton notes that people with bad visual imagery could think just fine.
It’s an unresolved debate
Imagery and the cognitive revolution: explain Paivio’s early cognitive paradigm regarding concrete and abstract words .
- Study using word pairs.
- Used concrete vs abstract words.
- Better memory for concrete words
- Conclusion: associating images with words improves memory.
- Led to the conceptual peg hypothesis –> concrete words allow the forming of visual images that other words can hold on to
Imagery and the cognitive revolution: explain Shepard and Meltzer’s 1971 experiment.
- Mental rotation
- They varied the angle of the comparison shape, and they measured the response RT
- Results: increased RT as the angle of rotation increases.
Imagery and perception: explain Lea’s criticism of Kosslyn’s original study.
- Increased distractors when scanning longer distances increased the RT
Explain Pylyshyn (2003) - Tacit Knowledge
Tacit knowledge - using real-world knowledge unconsciously to imagine.
In Kosslyn’s experiments, participants used the knowledge that it would take them longer to move greater distances
What are some experiments that support the spatial/travel hypothesis?
- Finke and Pinker (1982) –> briefly presented a display with four dots and then one with two arrows. The RT increased when the distance between the arrow and the dot increased
Have we resolved the imagery debate?
No. All results have alternative explanations –> e.g., tacit knowledge
What are some case studies about imagery and the brain
Farah (2000)
- Removed right occipital lobe from MGS.
- Reported smaller visual field and imagined visual field
- Objects filled up her imagined visual field faster when performing tasks like the mental walk task.
- Supports the relationship between mental imagery and perception.
Bisiach and Luzzatti (1978)
- Patient with neglect
- The patient imagined a familiar location and imagined looking at it from the other side.
- The neglected side changed when they looked at the image differently –> like when seeing it.
Counterfindings
- Patient with neglect, but only with images. There is no real neglect with real perception.
- RM –> damage to the occipital and parietal lobe. Okay perception but trouble with drawing from memory (requires imagery)
- CK –> visual agnosia. trouble identifying objects but no trouble drawing them.
What are some practical uses of imagery?
- Tool to improve memory
- Method of loci –> placing images at locations. Come up with familiar places and allocate new things to the different locations to connect images.
- Pegword technique –> use standard words (objects) and come up with an image to associate the new word to pegword.
- Reduce food cravings
Harvey et al. –> asked to imagine their favorite foods of favorite vacation places. Imagined food –> more food cravings. Then had them imagine non-food things visually or auditory. If they imagined them visually, that reduced their food cravings as there was more interference with the food image.
Kemps et al –> had people has a phone app and look at random patterns of dots when they had a craving. This reduced cravings.
Imagining something using the same mechanism interferes.
