Psychology 247 Cognitive Psychology
Representation of knowledge
Perceptual or analogical based representations
Erwin Segal
Back to syllabus
Describing a room
Giving directions: often we imagine ourselves on the road and describe the path that we might take and the on line information to consider, e.g., landmarks, distances, relative directions, geographical directions
Hoffding effect: ability to identify things in the environment. In order to recognize someone or something, the stimulation received from the object must engage some memorial representation of that object. Computationally, this requires a system to be able to pick up the appropriate information in the stimulus and have the available information structure in some representation to recognize it.
Evidence for analogical systems in memory
Shepard and Colleagues: Subjects' comparisons similarities of state outlines are similar whether they look at state outlines, or use their memorial representations. 
                                     Rotation of Objects
Posner: Matching of Case of letters. These results are similar to those of Cooper and Shepard theoretically. Subjects can create an image to use to compare with an expected incoming image.
Hierarchical Structure of images. Images are composed of components which are combined to form higher components, etc. (check text p. 122f (Reed, McNemara et al, Stevens and Coupe on map distortions)
Kosslyn has data that show that to form the identical image in different ways, has different hierarchical components and if there are more components creating the image takes longer. If one has an image of a scene, it takes longer to scan long distances than short distances.
Two memory systems?
Paivio and visual and verbal systems. Imageable words function differently than words that are not easily imageable.
Accuracy or detail of an image? e.g., How many stripes on a tiger? What are the angles of an imaged triangle?
Brooks found two tasks that showed different interference patterns. Thus there is selective interference depending upon the tasks a subject is doing.
Brain Localization of function
 The location in the brain of tasks using images seem to occur in the same places as similar tasks based on perception. Kosslyn has PET scans which demonstrate this and follow-up fMRIs by different people show some of the same things.
This does not mean that all vision takes place at a single location. Different tasks take place in different places even with the same stimuli. Mecklinger & Meinhausen (1998) showed that using ERP methodology, identifying whether the location of an object is new shows greater positive reactions in the frontal areas than does identifying whether the object is new, whereas the reverse is true in occipital brain loci.
Imaginal and Symbolic psychophysics.
When one compares two visual objects according to size, generally, the greater the difference in size, the faster one can make the decision. Interestingly, images have that same property. The greater the difference in size between two objects, e.g., one can say a horse is larger than a mouse, faster than she can say a rabbit is larger than a mouse. Moyer and Bayer taught subjects syllables associated with circle size. e.g., four circles 2 inch 1 1/2 inch, 1 inch and 1/2 inch diameter circles called 'nef,' 'ras,' 'jik' and 'lep' respectively. Reaction times to whether 'jik' is smaller than 'ras' is longer than 'jik' is smaller than 'nef.'

One can generate hierarchical structures to letter strings, words, melodies, and probably most other things. Sentences are hierarchically ordered as we will see later in the semester.
Johnson found that if a letter or a number sequence is learned in one structure, if the structure is changed people do not recognize the sequence. They find the new one difficult to learn. e.g. Learn RSV LD BWQ among others. Then learn  RS VLDB WQ among others.
Are visual images like visual perception? In certain ways they seem to be. They often use the same brain areas. Both Perception and imagery seems to develop by components in a hierarchical manner, rather than like a snapshot on a film. Buildup is by parts, and degradation is by parts.
In general we are much more flexible with our informational operations on visual percepts than we are on images. They are less likely to be in error because of faulty construction, although that happens in percepts also.
 

Barbara Tversky and colleagues: Perspective in memory
Erwin Segal: Deictic Shift, reading and writing from a particular perspective
Bob Lawson: Ordered list of objects
Segal and Greenspan: List searching

Mnemonics: Techniques of memory often make use of images. Images can be useful for memorizing lists.  One is a bun, Method of locations, Connected images, Strange images.

Back to syllabus