We investgated visual illusions of a vertical gradient by using minitures of a road in three experiments. The independent variables were the pitched visual pattern around the road and the pitched floor on which the observer stood. The dependent variable was the angle of the road that the observer adjusted to appear to be level in depth. In Experiment 1, the experimental room was pitched independently of the pitched floor on which the observer stood. Pitching the room was found to be effective for the illusion, but pitching the floor was not. In Experiment 2, the horizontally striped pattern of the sidewalls was pitched in the range of ± 30° and the height of the sidewalls was also varied. The illusion was found to be maximal for patterns pitched at ± 10°, but the sidewall height did not influence the illusion. In Experiment 3, six visual patterns that were produced by combining horizontal and vertical stripes were pitched at ± 10°. The results showed that the lattice pattern was the most effective, and the horizontal stripe was more effective than the vertical, in contributing to the illusion.
This study examined the effects of biased retelling by having participants retell negative experiences as positive autobiographical memories. Undergraduates in the biased-retelling condition (N=21) retold their experiences preparing for university entrance examinations as “happy”, while undergraduates in the recalling (control) condition (N=23) again narrated their actual experiences. Then both groups were asked to recall their initial experience. Their initial memories were compared to those after the biased retellings or repeated narrations. In the recall of the autobiographical memories after the biased retellings, the results showed significantly increased positive emotional words and decreased negative emotional words. The emotional values of the central and peripheral concepts of the harsh experiences changed in the direction of “happy” in the biased retelling condition compared to the repeated recalling condition. Furthermore, the changes in the emotional values were more prominent in the central concepts of undergraduates'experiences.