Citation 10 Mental Rotation PDF

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Citation 10 -- “Mental Rotation” 1. Goal of article: State the research questions and/or hypotheses being investigated (What are they trying to do?) (Four sentences to one paragraph)

Research Questions: how long does it take to rotate images in mind? Do we manipulate images in our mind, as we would manipulate real objects? Mental rotation experiments ask whether the manipulation of images is similar to the manipulation of real objects Classical studies form Shepard and Metzler (1971). Result of study was that we need longer for mental rotation with increasing angle between objects to rotate. The mean rotation speed follows real world physical properties of the stimuli, therefore might have real images in our mind that we rotate (60 degrees a second). 2.

List three (3) cognitive psychology terms important for the topic of the article, find their definitions or descriptions in any CogPsy textbook (give reference) and provide them here:

A. Mental models: knowledge structures that individuals construct to understand and explain their experiences; an internal representation of information that corresponds analogously with whatever is being represented (p. 301) B. Mental rotation: involves rotationally transforming an object’s visual mental image (p. 289) C. Functional-equivalence hypothesis: belief that although visual imagery is not identical to visual perception, it is functionally equivalent to it. (p. 287) Reference: Sternberg, R. J. & Sternberg K. (2012) Cognitive Psychology Sixth Edition. 3.

Describe ALL the dependent variables for the designated experiment: a. Provide an operational definition b. Name the units it was measured in DV: Reaction time for “same pairs” measured in seconds.

4.

Describe ALL the independent variables for the designated experiment: c. Name each variable d. List its levels e. State the statistical test(s) that was/were used to analyze the data f. If there are more than one independent variable, state the factorial design IV: The angle rotation and pairs, Factorial design: 10x2 Statistical test used is a t-test and linear regression 5.

Describe how the experiment was conducted, i.e., what was the procedure: (4-6 sentences)

Eight adult participants were presented with 1600 pairs of perspective line drawings. For each pair the participant was asked to pull a right-hand lever as soon as he determined that the two drawings portrayed objects that were congruent with respect to three-dimensional shape and to pull a left-hand lever as soon as he determined that the two drawings depicted objects of different three-dimensional shapes. For each of the ten objects, 18 different perspective

projections corresponding to one complete turn around the vertical axis by 20 degree steps, which were generated by digital computer and associated graphical output. Seven of the 18 perspective views of each object were then selected so as to avoid any views in which some part of the object was wholly occluded by another part and yet to permit the construction of two pairs that differed in orientation by each possible angle, in 20 degree steps, from 0 degrees to 180 degrees. These 70 line drawings were then reproduced by photo-offset process and were attached to cards in pairs for presentation to the participants. Half of the "same" pairs (the "depth" pairs) represented two objects that differed by some multiple of a 200 rotation about a vertical axis. For each of these pairs, copies of two appropriately different perspective views were simply attached to the cards in the orientation in which they were originally generated. The other half of the "same" pairs (the "picture-plane" pairs) represented two objects that differed by some multiple of a 20 degrees rotation in the plane of the drawings themselves. For each of these, one of the seven perspective views was selected for each object and two copies of this picture were attached to the card in appropriately different orientations. Altogether, the 1600 pairs presented to each participant included 800 "same" pairs, which consisted of 400 unique pairs (20 "depth" and 20 "picture-plane" pairs at each of the ten angular differences from 0 degrees to 180 degrees), each of which was presented twice. The remaining 800 pairs, randomly intermixed with these, consisted of 400 unique "different" pairs, each of which was presented twice. Each of these "different" pairs corresponded to one "same" pair of either the "depth" or "picture-plane" variety in which, however, one of the three-dimensional objects had been reflected about some plane in three-dimensional space. Thus the two objects in each "different" pair differed, in general, by both .a reflection and a rotation. The 1600 pairs were grouped into blocks of not more than 200 and presented over eight to ten 1-hour sessions. 6.

Identify all the main effects and interactions (if the design is factorial). Make sure you state the main effect for EACH independent variable you named in (4): a. Provide the statistical statement (t- or F-statement) b. Explain each statement in plain English

3.2 percent of the responses were incorrect (ranging from 0.6 to 5.7 percent for individual participants). The reaction-time data presented included only the 96.8 percent correct responses. In all 16 cases the functions were found to have a highly significant linear component (P .05, in all cases). The overall mean reaction time for these pairs was found to be 3.8 seconds; nearly a second longer than the corresponding overall means for the "same" pairs. The reaction times were still linear and were no more than 20 percent lower in the "pure" blocks of presentations, in which the participants knew both the axis and the direction of the required rotation in advance of each presentation) than in the "mixed" blocks, in which the axis of rotation was unpredictable. This suggests that 80 percent of a typical one of these reaction times may represent some such process as "mental rotation" itself, rather than a preliminary process of preparation or search. 7.

Steps or conclusions suggested by the article (One paragraph): a. How is each research question listed in (1) answered? b. What do the data mean?

Participants rotated an image of an object in their mind to compare whether it was similar to or different from another object. The larger the angle, the longer to decide whether it is

the same or different. There was an almost perfect linear relationship between RT and angular difference (degrees). Shepard and Metzler's (1971) experiment on mental rotation found that participants took longer to mentally rotate an image a greater number of degrees of difference between two images. This implies that mental imagery may share similar features to perception. Performance was good (above 96%). The time taken to recognize some objects was linearly related to the degree of rotation necessary to create identical images. People mentally rotate objects at constant speed. There is a linear relationship between the objects rotated. They found that the time it took participants to decide if the two drawings depicted the object or a mirror image reversal was directly proportional to the angle of rotation between the drawings. This suggests that mental rotation of a visual image operates under similar properties of rotations of actual objects. Concluded that participants performed the task by mental rotation of the drawing. The time it took participants to come to a decision was the same for rotations in the picture and depth. 8.

Extend Shepard and Metzler’s findings to another imagery task. What would they predict about how long it would take for participants to “mentally travel” between different locations on a map? Use evidence from Kosslyn’s experiments as well. (One-two paragraphs).

Shepard & Metzler (1971) participants mentally rotated one object to see if it matched another object. Kosslyn (1973; 1978); Memorize picture, create an image of it. In the image of it, move from one part to another. It took longer for participants to mentally move long distances than shorter distances.1978; Island with 7 locations and 21 trips. It took longer to scan between greater distances. Conclusion regarding visual imagery is visual imagery is spatial. Shepard & Metzler experiment shows mean reaction times were dependent on how much the stimulus had to be rotated. Kosslyn found that, like perception, imagery is spatial. Spatial representation: knowledge is contained in the image itself. Imagine elephant, and then rabbit next to elephant, rabbit viewed as small. Imagine a fly and rabbit beside each other; the rabbit is viewed as large. This shows that we are slower when an image is small. If visual imagery is roughly equivalent to actually viewing an object, we should be faster to make decisions about small details when the size of the image is bigger compared to when it is smaller. This is evidence that perception and imagery use the same mechanisms. Maybe, rather than using random block shapes, there could be an experiment conducted using real pictures or 3d images and see how the results vary 9.

Imagine that in some participants’ data reaction times have not increased as angle of rotation increased. Give some reasons why this might have happened. There are at least two very solid reasons why this could happen. In order to answer this question, you need to imagine how things are rotating from angle 00 to angle 2400. (One-two paragraphs).

If some participants had data reaction times that did not increase as the angle of rotation increased, maybe the participants had prior experience in completing similar tasks or that maybe the type of figure they were judging was affecting the results. 10.

APA-style reference for both articles.

Shepard, R., Metzler, J. (1971). Mental rotation of Three-dimensional Objects. Science, 171 (3972) 701-703. Retrieved from www.jstor.org/stable/1731476

Masters, M.S. (1998) The gender difference on the mental rotation test is not due to performance factors. Memory and Cognition, 26, 444–448...