Stereo-motion cooperation and the use ofmotion disparity in the visual perception of 3-D structure

When an observer views a moving scene binocularly, both motion parallax and binocular disparity provide depth information. In Experiments lA-1C, we measured sensitivity to surface curvature when these depth cues were available either individually or simultaneously. When the depth cues yielded comparable sensitivity to surface curvature, we found that curvature detection was easier with the cues present simultaneously, rather than individually. For 2 of the 6 subjects, this effect was stronger when the component of frontal translation of the surface was vertical, rather than horizontal. No such anisotropy was found for the 4 other subjects. If a moving object is observed binocularly, the patterns of optic flow are different on the left and right retinae. We have suggested elsewhere (Cornilleau-Pérès & Droulez, in press) that this motion disparity might be used as avisual cue for the perception of a 3-D structure. Our model consisted in deriving binocular disparity from the left and right distributions of vertical velocities, rather than from luminous intensities, as has been done in classical studies on stereoscopic vision. The model led to some predictions concerning the detection of surface curvature from motion disparity in the presence or absence of intensity-based disparity (classically termedbinocular disparity). In a second set of experiments, we attempted to test these predictions, and we failed to validate our theoretical scheme from a physiological point of view.     

Illusory conjunctions and the cerebral hemispheres

Two visual half-field experiments tested Moscovitch’s (1979) proposition that cerebral asymmetry does not concern the earliest perceptual stages but only later processing. Subjects were briefly shown displays that included one (Experiment 1) or two (Experiment 2) types of forms differing in size and which, according to previous evidence, might lead to opposite laterality effects. Laterality effects were assessed for correct detections and for illusory conjunctions, both in terms of raw detection scores and in terms of perceptual discriminability (dr scores). In Experiment 1, displays included either rectangles or triangles. In the first case, the target was a cross; in the second case, it was a Star of David. A hemifield x size interaction was observed both on correct detections and on associated discriminability. Yet, no such interaction was obtained for illusory conjunctions or for associated d’ scores. In Experiment 2, the two types of forms were presented simultaneously, with the small ones either inside or outside the large ones. No laterality effects were observed. Some implications of these data for both hemispheric asymmetry and feature integration issues are discussed. The results suggest that early preattentive processes of feature extraction are not lateralized, whereas some integrative mechanisms, such as Treisman’s (1988) focal attention, may operate differently in the two hemispheres.     

Art,logotherapy, and the unconscious God

In this article the author outlines how art can be used in Logotherapy and Existenzanalyse to help the client uncover, discover, and make use of the meaning and spiritual potentials in his or her life. In Logotherapy and Existenzanalyse art can be used to help over-come fear of verbal communication, to help overcome fear of the spiritual and meaning potentials in the client's life, and to help the client gain awareness and contact with the unconscious God.     

Psychotherapy with families of psychosomatic patients

Paradigmatic complexes in family psychotherapy have been indicating a revolutionary change and the creation of new paradigms for the past thirty years. Starting with the application of the general systems theory and the development of those concepts that have been emerging regarding psychosomatic illnesses we discuss the epistemological confusion created, the methodological problems and the dissociation between theory and practice. We suggest a double process of investigation of the family structure using a knowledge of the basic attitudes and the development of a psychotherapy programme within the family of the psychosomatic patient.     

Ethnicity of Defendants and Jurors as Influences on Jury Decisions1

To assess the influence of ethnicity on jury decisions, 480 subjects viewed a videotaped trial of an Anglo or Hispanic defendant. Anglo or Hispanic majority 6-person juries deliberated until a unanimous verdict was reached. The juries that convicted the defendant were asked to determine sentence length and to provide a probation/ parole recommendation. Anglo majority juries convicted the defendant significantly more (M= 79%) than did the Hispanic majority juries (M= 52%), x²= 5.45, p < 0.02. No main effect of defendant ethnicity was obtained, but there was an interaction between the defendant and the jury's ethnicity, x²= 5.41, p < 0.02. Anglo majority juries were more lenient with the Anglo defendant, but the Hispanic majority juries did not differ in their conviction rates. No significant effects were obtained for sentence length. Differences in probation/parole recommendations were a function of jury ethnicity, F(l, 15) = 4.74, p < 0.05. Anglos were more likely to recommend that the defendant serve the full term of the sentence. These results are interpreted in terms of stereotyping and are discussed regarding their implications for a defendant's constitutional right to a fair trial.     

Search behaviour of cats (Felis catus) in an invisible displacement test: cognition and experience

An invisible displacement test was administered to cats in order to test the hypothesis that search behaviour in this species is influenced by their limited capacity for object permanence as well as by their previous experience with the environment. Experiment 1 compared three groups of cats in a five-choice hiding task in which the hiding places could be discriminated by their spatial positions. Two groups received a visible displacement training before the invisible displacement test and one group did not. Experiment 2 compared two groups of trained subjects in the same task, but the hiding places could be discriminated by spatial and visual cues. The results confirmed that cats are unable to solve problems with invisible displacements. The visible displacement training improved their performance, but was not sufficient to make them succeed. Experience with the hiding potential of the covers also gives more persistence to search behaviour. Finally, the distribution of search attempts is not determined by the proximity to the target and is influenced only partially by the subjects' previous experience. Like Stage 5 infants, cats rely mainly on their immediate perception. They search for an object in the last location they have seen it disappear or under the nearest cover from this location.     

Grading the ‘cultural literacy’ project

The essay examines the argument advanced by E.D. Hirsch, Jr., for instituting ‘cultural literacy’ as a fundamental priority of schools. A number of confusions and equivocations in Hirsch's reasoning are identified, and the propensity of his project to indoctrinate is exposed. Among the features of Hirsch's argument shown to be troubling are his shifting construal of ‘language’, his inconsistency about the requirements of cultural literacy, and his uncritical relation to traditional images of the American past and present. The upshot is to raise the question why Hirsch's project has elicited wide support and praise.     

Changes in information as a function of a culturally appropriate smoking cessation community intervention for Hispanics

Tested a 7-month, media-based, community intervention among Hispanics in San Francisco designed to change levels of information on the damaging effects of cigarette smoking and on the availability of culturally appropriate cessation services. Three community-wide surveys of Hispanics were conducted with independent random samples, two as baselines (n = 1,660 and 2,053) and one postintervention (n = 1,965). Results showed that changes in the level of awareness of cessation services had taken place after implementation of the intervention. Furthermore, those changes took place primarily among the less acculturated Spanish-speaking Hispanics who were the target of the intervention. The changes in information reported here demonstrate that a culturally appropriate information dissemination campaign that utilizes multiple channels can produce changes in a community's level of information even when the campaign is implemented for a relatively short period.