Many experiments have been done on the effects of the Rod and Frame Apparatus on different groups of subjects (i.e., athletes, the disabled, and individuals of different ages) (Zoccolotti et al, 1997; DiLorenzo and Rock, 1982; Shinar, 1977; Bergemann, 1970; McLeod, 1985 and 1987). This experiment was designed to help discover the effects of a person's balance on field dependence and independence. This experiment uses the Rod and Frame Apparatus, a device helpful in determining field dependance and independence. The Rod and Frame Apparatus is a rectangular box. One side of the box is open, for subjects to look into, and the other end is closed. The closed end can be independently rotated both clockwise and counterclockwise. On the inside of the closed end of the box, is a frame with a line in the middle of the frame. When the back of the box is rotated, the frame on the inside rotates as well. Subjects are to rotate the box while looking into it to make the line vertical. Experimenters hypothesized that when subjects are spun in the same direction as the Rod and Frame Apparatus is rotated, the illusion will become stronger. When subjects are spun in the opposite direction that the Rod and Frame Apparatus is rotated, the illusion will become weaker.

The subjects used in this experiment were twenty-five randomly selected college undergraduates. The materials used were the Rod and Frame Apparatus and a swivelling desk chair. Subjects were randomly put into two test groups and a small control group. The control group had five subjects in it. For subjects in the control group the Rod and Frame Apparatus was not tilted at all. The other two groups each had ten subjects in it. In these groups the Rod and Frame Apparatus was either tilted 20 degrees clockwise or 20 degrees counterclockwise. All three conditions had two parts. Part one consisted of having the subject sit in the swivelling chair and try to verticalize the line in the box. The subjects would have ten seconds to do this task. In the second part of the conditions, subjects were spun clockwise for five rotations while sitting in the swivelling chair. They were then to try to verticalize the line once again. They were also given ten seconds to complete this task.

Results

After each condition had been run and all data collected, the mean for each condition was found. The control group was not included in these calculations because the five subjects' degree of error was exactly, or very near zero. In the condition with the box tilted 20 degrees clockwise, the degrees of error for two subjects were not calculated into the mean because they were such large outliers. The adjusted mean for the 20 degrees clockwise condition was 1.0 degree of error for the unspun condition and 1.9 degrees of error for the spun condition. The mean for the 20 degrees counter-clockwise condition was 2.2 degrees of error for part one and 1.0 degrees of error for part two.

Figure 1: Graph of the degrees of error in a test of balance and field dependence and independence. This graph shows the mean of the two test conditions. When the box was tilted 20 degrees to the right (clockwise) the mean was 1.0 degrees of error when the subjects had not been spun and 1.9 degrees of error when they had been spun. When the box was tilted 20 degrees to the left (counterclockwise) the mean was 2.2 degrees of error when the subjects had not been spun and 1.0 degrees of error when they had been spun.

Discussion

As can be seen in figure 1, there was no effect on the strength of the illusion just by spinning the subjects or just by tilting the Rod and Frame Apparatus. It is shown however, that there is a powerful effect on the illusion when the two (spin and tilt) are combined. The spin distorts the judgement of the subjects when they are trying to verticalize the rod. When the frame is tilted clockwise (to the right) and the subjects are spun to the right, the illusion is made stronger. When the frame is tilted counter-clockwise (to the left) and the subjects are then spun to the right, the illusion is no longer as strong. Spinning the subjects in the opposite direction of the frame tilt seems to compensate for the illusory effects of the Rod and Frame Apparatus. These effects seem only to occur when illusory conditions are already present. These results are similar to those found by Shinar (1977) in his study of the addition of cues on the perception of verticality. In this study the added cue would be the spin added to the subjects by the researchers.

References

Shinar, David. 1977, Additivity of cues in perception of verticality. Perceptual & Motor Skills, 44, 1327-1332.

Zoccolotti, Pierluigi; Antonucci, G.; Daini, R.; Martelli, M.; Spinelli, D. 1997, Frame-of-reference and hierarchical-organization effects in the rod-and-frame illusion. Perception, 26, 1485-1494.

DiLorenzo, Joseph R. and Rock, L. 1982, The rod-and-frame effect as a function of the righting of the frame. Journal of Experimental Psychology: Human Perception and Performance, 8, 536-546.

Bergemann, Karen. 1970, The effects of chronic disability on field dependence-independence. Graduate Research in Education & Related Disciplines, 5, 109-123.

McLeod, Bill. 1985, Field dependence as a factor in sports with preponderance of open or closed skills. Perceptual & Motor Skills, 60, 369-370.

McLeod, Bill. 1987, Sex, structured sport activity, and measurement of field dependence. Perceptual & Motor Skills, 64, 452-454.
McLeod, Bill. 1987, An examination of development trends in field dependence among age groups of 13 to 21 years of age. Perceptual & Motor Skills, 64, 117-118.

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