The effect of angle between the oblique lines on the decrement of the Müller-Lyer illusion with extended practice

Early work on the Müller-Lyer illusion had indicated that it disappears with extended practice. The present experiment failed to confirm this finding. The magnitude of the illusion decreased for approximately 500 trials, but showed no further change over an additional 500 trials. The rate of the practice decrement was inversely related to the size of the angle formed by the oblique lines of the figure.     

The role of phenomenal displacement on the perception of the visual upright

Tilt invariably involves the factor of displacement. A clockwise rotation of a rod, for example, results in the top being displaced to the right and the bottom to the left. The question was raised as to which is primary, displacement or tilt. Through a series of experiments, apparent tilt was found to be the perceptual outcome of phenomenal displacement. In addition, gravity seemed to play no significant role in determining the visual upright. Therefore, the conventionally accepted field theory of apparent verticality was rejected and the visual upright was interpreted according to principles which govern the perception of motion and radial direction.     

The Personality of Select Theological Students

When 72 male students in a southern theological institution were compared by the manner in which they intended to fulfill their religious vocation (i.e., as missionaries, pastors, or religious education workers), a homogeneity of personality behavior was observed on each of 16 factors. The total sample, however, was reported to be substantially and significantly different from the general population on four factors. No significant difference was reported among the three groups in their need for social approval as measured by the Marlowe-Crowne SDS.