The recovery of structure from motion: no evidence for a special link with the convergent disparity mechanism

Convergent and divergent stereo mechanisms were compared in their ability to recover structure from motion. Contrary to a recent result reported by Richards and Lieberman, no difference in their performance was found; both mechanisms appeared equally capable of supporting the perception of good structure from motion. Possible reasons for the disparate results are discussed.     

AN EMPIRICAL APPRAISAL OF THE PRCA FOR MEASURING ORAL COMMUNICATION APPREHENSION

Since 1970 about 80% of the research on oral communication apprehension has used one of two versions of McCroskey's Personal Report of Communication Apprehension. The original 20-item PRCA was introduced for the purpose of measuring apprehension beyond the traditional public speaking context. Although the PRCA-20 is reliable, some serious criticism of it has centered on its ability to tap interpersonal behavior outcomes. In an attempt to bolster its interpersonal applicability, five “interpersonally-oriented” items were added to form the PRCA-25. The studies reported herein demonstrate that both versions fail to possess sufficient reliable variance to be applicable to contexts other than public settings. In addition, it was found that the interpersonal items are a separate component of the PRCA, and as such, do not justify being treated equal in terms of additivity and, therefore, reduce the construct integrity of the PRCA.