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.     

Integration of stereo and texture cues in the formation of discontinuities during three-dimensional surface interpolation

A series of stereograms are presented which demonstrate that texture boundaries can strongly influence the perception of discontinuities between neighbouring three-dimensional (3-D) surfaces portrayed by means of stereo cues. In these demonstration figures, no stereo information is available in the immediate vicinity of the boundary between the two 3-D stereo surfaces because all texture in that region is removed in one eye's view. On the other hand, various forms of texture boundary information are provided in the resulting monocular region. This stimulus paradigm is used to explore the question: what influence does texture boundary information have on the nature of the perceived 3-D surface that is interpolated between two stimulus regions which carry stereo cues? It is shown that if a clear-cut texture boundary is present in the monocular region then this is used by the human visual system to fix the perceived location of 3-D crease and step surface discontinuities between the stereo regions. Collett (1985) explored this issue with a similar methodology and reported weak and unreliable assistance from monocular texture boundaries in helping shape 3-D stereo surface discontinuities. The strong and robust phenomena demonstrated here seem to rely on two main differences between the present stimuli and those of Collett. In the present stimuli, figurally continuous textures containing strong texture boundaries are used, together with a technique for minimising the complications, including binocular rivalry, that arise from the borders of the stimulus regions present in only one half of each stereogram.     

An Evaluation of the Word Triad Method for Monitoring Spelling Progress

Although spelling skill progress has typically been studied within the context of students' responses to written story starters (Deno, Marsten, & Mirkin, 1982; Fuchs & Fuchs, 2011; Hosp, Hosp, & Howell, 2007; Shinn & Shinn, 2002), there has been little research conducted within a curriculum-based measurement framework that has studied spelling progress monitoring on a weekly basis throughout an entire school year. The authors evaluated spelling progress using word triads, defined as a group of 3 words (with the same number of letters) that have a similar phonetic or morphological structure. Successful spelling of word triads as the unit of analysis has the potential to be more useful diagnostically to teachers than successful spelling of single words as the unit of analysis. An alternating series of three 15-word spelling tests were administered weekly to 10 third- and fourth-grade classrooms in the same school district throughout the school year for 8 rounds (1 round = 3 weeks of different but phonetically and/or morphologically similar word lists). Results indicate steady progress throughout the school year in the correct spelling of word triads (despite teacher reporting of no explicit spelling instruction in classrooms using in the words employed in the study). Correlations between the number of correctly spelled word triads with standard scores from a group-administered communication arts test were significant and comparable to alternate spelling test scoring methods. The authors conclude with limitations of the study and implications for practitioners.     

THE FATHER,THE FATHER FUNCTION,THE FATHER PRINCIPLE: SOME CONTEMPORARY PSYCHOANALYTIC DEVELOPMENTS

The author discusses Freud's thinking on the role of the father, as well as that of later French theoreticians. To illustrate his remarks, he draws on the poetry of Carlos Drummond de Andrade (1912–1987), a Brazilian poet whose work often dealt with themes of the father, the family, and his own paternal relationship. The author also discusses the psychic formation of the father principle and how this may be evident in the clinical analytic setting, even when the analyst's approach privileges field theory, intersubjectivity, or other concepts emphasizing the relationship between analyst and patient.     

Flirtatious Communication: An Experimental Examination of Perceptions of Social-Sexual Communication Motivated by Evolutionary Forces

Guided by Relational Framing and Parental Investment Theories, this investigation examined experimentally induced flirtatious interactions. United States undergraduates (N?=?252) from the Mid-Atlantic region viewed a flirtatious interaction and rated a confederate on physical and social attraction, affiliation, dominance, and conversational effectiveness. Generally, it was hypothesized that different flirting motivations would lead to different evaluations of the flirters, and perceptions of flirters would vary based on gender. Results revealed that men were evaluated as more dominant and affiliative than women when flirting, but dominance in men was not perceived as attractive or conversationally effective. In addition, men??s attraction to women increased significantly when women flirted for sexual motives, and women??s attraction to men decreased significantly when men flirted for fun. Overall, the results provide mixed support for both theories.     

Does visual texture discrimination precede binocular fusion?

Various stereoscopic demonstrations are presented which indicate that visual texture discrimination is based on processes which occur after, or at the same time as, the binocular combination of images from the two eyes. Monocularly invisible texture regions can become apparent, and monocularly visible regions can be hidden, by the processes of binocular fusion.     

The 'ecological' probability density function for linear optic flow: implications for neurophysiology

A theoretical analysis of the recovery of shape from optic flow highlights the importance of the deformation components; however, pure deforming stimuli elicit few responses from flow-sensitive neurons in the medial superior temporal (MST) area of the cerebral cortex. This finding has prompted the conclusion that MST cells are not involved in shape recovery. However, this conclusion may be unjustified in view of the emerging consensus that MST cells perform nonlinear pattern matching, rather than linear projection as implicitly assumed in many neurophysiological studies. Artificial neural models suggest that the input probability density function (PDF) is crucial in determining the distribution of responses shown by pattern-matching cells. This paper therefore describes a Monte-Carlo study of the joint PDF for linear optic-flow components produced by ego-motion in a simulated planar environment. The recent search for deformation-selective cells in MST is then used to illustrate the importance of the input PDF in determining cell characteristics. The results are consistent with the finding that MST cells exhibit a continuum of responses to translation, rotation, and divergence. In addition, there are negative correlations between the deformation and conformal components of optic flow. Consequently, if cells responsible for shape analysis are present in the MST area, they should respond best to combinations of deformation with other first-order flow components, rather than to the pure stimuli used in previous neurophysiological studies.     

Confirmatory Factor Analysis and Profile Analysis via Multidimensional Scaling

This paper describes the Confirmatory Factor Analysis (CFA) parameterization of the Profile Analysis via Multidimensional Scaling (PAMS) model to demonstrate validation of profile pattern hypotheses derived from multidimensional scaling (MDS). Profile Analysis via Multidimensional Scaling (PAMS) is an exploratory method for identifying major profiles in a multi-subtest test battery. Major profile patterns are represented as dimensions extracted from a MDS analysis. PAMS represents an individual observed score as a linear combination of dimensions where the dimensions are the most typical profile patterns present in a population. While the PAMS approach was initially developed for exploratory purposes, its results can later be confirmed in a different sample by CFA. Since CFA is often used to verify results from an exploratory factor analysis, the present paper makes the connection between a factor model and the PAMS model, and then illustrates CFA with a simulated example (that was generated by the PAMS model) and at the same time with a real example. The real example demonstrates confirmation of PAMS exploratory results by using a different sample. Fit indexes can be used to indicate whether the CFA reparameterization as a confirmatory approach works for the PAMS exploratory results.     

Orientation of stimuli and binocular disparity coding

An experiment is described which attempts to relate physiological work on disparity coding in the cat to a psychophysical situation using human subjects and Julesz stereograms composed of small line elements. It was found that depth perception occurred only if matching disparate lines in each stereogram shared a similar orientation. Depth began to deteriorate if an orientation difference exceeded 10° and it was extinguished at about 60°. The results are interpreted as supporting the hypothesis that shape-sensitive disparity detectors of the kind found in the cat exist also in man.