In the present experiments, we attempted to evaluate the modification of the strength of the Poggendorff illusion as a function of the different orientation of a parallel-line texture filling the space between the vertical lines. In Experiment 1, the standard version of the PoggendorfI configuration was tested against four different parallel-line textures oriented at 0 0 , 4 5 0 , 90 0 , and 135 0 with respect to the obliques. The results showed that the illusory effect was a linear function of the progressive discrepancy between the angle of the lines of the texture and that of the obliques. In Experiment 2, we tested the same textures used in Experiment 1 after the elimination of the two vertical lines. The data obtained approximated a linear function, as in the previous experiment, but the alignment errors were consistently lower. The statistical analysis performed on the data of all eight experimental conditions shows that both factors-texture and presence/absence of verticals-were significant, but most of the effect was due to the texture factor. The results may be interpreted through the "perceptual compromise hypothesis," originally proposed for the bisection forms of the PoggendorfI illusion, but with important modifications. The data are also discussed in terms of their implications for other theories proposed for the PoggendorfI illusion.The Poggendorff illusion is shown in Figure I; in the original version of this optical-geometrical illusion, two collinear obliques separated by a pair of parallels appear displaced from their physical alignment. In this case, the upper right oblique appears too high to be aligned with the prolongation of the lower left oblique.There are several accepted fmdings on this illusion: The apparent displacement of the transversals is increased when the angles are more acute; increasing the separation between the parallels increases the effect; a horizontal or vertical orientation of the transversal reduces the illusion; and the distortion does not depend on the straightness of the separating elements (Coren & Girgus, 1978).Despite general agreement on these empirical findings, the illusory effect has been explained within different theoretical frameworks. One type of explanation involves "structural factors" like optical blur and lateral inhibition that could induce distortions in the region of the intersections between lines, for example, expansion of acute
Antecedents of six emotions in two different Italian subcultures were studied through the analysis of their verbal representations. One hundred participants (50 from northern Italy and 50 from southern Italy) were asked to write two short stories about each of the six emotions considered (anger, disgust, fear, sadness, happiness, and surprise). These stories were scored at six levels of progressively higher abstraction. The results showed that for each emotion there is a modal category, which frequently was identical, and some secondary categories that varied considerably with culture. Southern Italians showed significantly more interest in other people then northern Italians, both in the sense of worrying more about others' negative behavior and considering it very important to feel good about other people. Northern Italians tended to center their attention on the self; they reported greater worry about self-achievement than about relationships with other people and feared personal harm more than loneliness.
The relationship between instantaneous tangential velocity and radius of curvature (power 1/3) that is characteristic of adult subjects was found to be already present in children 3 to 11 years old. The correlation coefficient between these two parameters increases gradually with age without apparent discontinuities. However, even at the upper limit of the age range examined, the values are still lower than in the adults.
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