What is the “front” of a simple geometric form?

A total of 670 undergraduate Ss were tested in three studies conducted in an attempt to define a set of cues that minimally specify perceived “frontness” and “backness” of objects. In Experiment I, Ss were instructed to identify the “front” and “back” of printed squares to which no, one, or two circles were attached. In Experiment II, different Ss made the same kind of judgment to a wider range of geometric forms. In Experiment III, different Ss judged the direction of “imagined” movement of forms from Experiment I. The results indicated that the “front” and “back” are asymmetric opposite sides, with “front” the side most different from the rest and the side toward which the form is imagined to be moving.     

Some rao-guttman relationships

An examination of the determinantal equation associated with Rao's canonical factors suggests that Guttman's best lower bound for the number of common factors corresponds to the number of positive canonical correlations when squared multiple correlations are used as the initial estimates of communality. When these initial communality estimates are used, solving Rao's determinantal equation (at the first stage) permits expressing several matrices as functions of factors that differ only in the scale of their columns; these matrices include the correlation matrix with units in the diagonal, the correlation matrix with squared multiple correlations as communality estimates, Guttman's image covariance matrix, and Guttman's anti-image covariance matrix. Further, the factor scores associated with these factors can be shown to be either identical or simply related by a scale change. Implications for practice are discussed, and a computing scheme which would lead to an exhaustive analysis of the data with several optional outputs is outlined.     

Vibrotactile magnitude production scaling: A method for studying sensory-perceptual responses of stutterers and fluent speakers

The method of vibrotactile mangitude production scaling was used to determine the tactile sensory-perceptual integrity for the dorsum of the tongue and thenar eminence of the right hand for 10 fluent speakers and 10 stutterers. It was discovered that both groups performed the task in a similar manner for the thenar eminence of the hand (a nonoral structure) but in a dissimilar manner for the tongue (an oral structure). From these data, it is suggested that the stutterers may maintain a different internal sensory-perceptual process for the tactile system involved in the speech process. The possibility exists that stuttering, for some, may be an “internal disorder” of the tactile-proprioceptive feedback mechanism that is directly involved in speech production.