Mental Imagery

1. Mental Imagery Chapter 10

2. Historical Overview • 3 basic ages of mental imagery: • the prescientific period known as the philosophic period • the measurement period • the cognitive and neurocognitive period

3. Current debate... • Is visual imagery really visual or is it governed by general-purpose cognitive processes? • When I “image” a tree, the same (or very similar) neurons/processes are activated as when I originally saw the tree • Representations used in imagery are not the same as those used in real perceptions.

4. 3 Theories... 1. Pavio’s Dual-Coding Hypothesis 2. Conceptual-Propositional Hypothesis 3. Functional-Equivalency hypothesis

5. Paivio's Dual-Coding Theory • The basic tenant of this theory is that information is mentally represented either in a verbal system or a nonverbal (analogical) system (or both). • Each system contains different kinds of information. • Each concept is connected to other related concepts in the same system and the other system. • Activating any one concept also leads to activation of closely related concepts.

7. Basic Result: Paivio (1971) • Give S's a long list of pictures or words to remember. • Later, test memory with either a recall or recognition memory test. • S's recall more pictures than words.

8. Basic Result: Paivio (1971) • Explanations: 1) The Imagen system has superior memory abilities to the Logogen system. 2) Representing ideas in both systems is superior to representing ideas in only one system.

9. Basic Result: Paivio (1971) • which of the explanations is correct? • Compare: • Memory for Verbalizable and Nonverbalizable pictures. • High-Imagability words (e.g., DESK) and Low-Imagability words (e.g., EFFORT). • S's instructed to form mental images of words and S's not instructed to form images of words. • Results: Across all these situations, the evidence consistently supports claim that having two representations = superior memory.

10. Can using dual coding ever interfere with/disrupt memory? • Schooler & Engstrom-Schooler (1990) • S's are shown a videotaped robbery. (This creates a visual memory.) • S's then either: 1) Are asked to imagine the robber. 2) Are asked to describe the robber. 3) Are asked to do a series of math problems. • S's complete a recognition memory test picking the robber out of a lineup of eight persons.

11. Results:Creating two codes can disrupt memory for information that is only represented in one code.

12. Another example: Wilson & Schooler (1991) • S's tasted different kinds of strawberry jam and either: • thought about it's taste • described it's taste. • S's then rated the quality of each jam.

14. conceptual-propositional hypothesis (Anderson and Bower) • Taking conservation approach, claimed wasn’t scientifically viable to suggest that memories are carried in memory like photos

15. conceptual-propositional hypothesis (Anderson and Bower) • we store interpretations of events, whether they be verbal or visual, rather than the imaginal components. • Anderson and Bower explain that concrete concepts are coded by a rich set of predicates that bind concepts together. ..."the only difference between the internal representation for a linguistic input and a memory image is detail of information"

16. conceptual-propositional hypothesis (Anderson and Bower) • Anderson and Bower’s conceptual-propositional hypothesis is a good model theoretically • The hypothesis does have trouble accounting for some imaginal processes

17. Functional-equivalency • The functional-equivalency hypothesis was first proposed by Shepard and Kosslyn and states that imagery and perception are extremely similar. • Shepard and Kosslyn introduced mental rotation of visual stimuli in memory. • Relationship between time required for a specific mental rotation and the actual degrees of rotation

18. Functional-equivalency • Conclusion… • Visual images reflect internal representations that operate in a way that is analogous to the functioning of the perception of physical objects.

19. Neurocogntitive Evidence • Many studies haven been done to obtain neurocognitive evidence for supporting the concept of mental imagery. • People who have damage to the left hemisphere have trouble with verbal memory while patients with damage to the right hemisphere have trouble with visual material. • findings support dual-coding hypothesis

20. Neurocogntitive Evidence • Different areas of brain are associated with different cognitive tasks • visual imaginal tasks and vision seem to be situated in similar locations in the brain • visual imaginal tasks, which require associative knowledge, activate brain regions affiliated with memory and vision • Support functional-equivalency

21. cognitive map • a map that allows us to navigate through the world. • Thorndyke and Hays-Roth (1982) found two types of knowledge that are used in moving about from day to day:Route Knowledge and Survey Knowledge.

22. cognitive map • Route knowledge is the knowledge that we draw on for getting around. • If I gave someone directions to my house, I am using Route Knowledge. • Survey Knowledge is knowledge that allows us to know understand the general spatial relationships that are involved. • I could tell the person that my house was south of the University.

23. cognitive map • Mental maps tend to be biased by the person drawing them. • In a map drawn by a student in Australia, the Australian continent was at the top of the map instead of the bottom.

24. Synesthesia: The Sound of Colors • Synesthesia is a condition where sensations usually experienced in a single modality are experienced in two modalities. • This conditiongive psychologists some very interesting data and research. • Some examples of synesthesia are receiving an auditory signal or sensation in a visual modality, where it obviously shouldn’t be.

25. Synesthesia: The Sound of Colors Seeing the words to OVER THE RAINBOW, a form of synesthesia.