A neuro-cognitive visual system for object recognition based on testing of interactive attentional top-down hypotheses

We propose an extension of a systemic model for object recognition formulated by Rybak et al (1998 Vision Research 38 2387-2400) which is based on the functional organisation of the visual systems in primate brains. In contrast to the learning and recognition scheme of Rybak et al we do not assume a behavioural paradigm, i.e. a visuomotor programmed scanpath that determines the sequence of foveation on the different parts of the object. As in the basis architecture of Rybak et al, the system modules are separated into 'what'-like subsystems corresponding to the ventral occipito-inferotemporal visual path and 'where'-like complexes analogous to the dorsal occipito-parietal visual path. The 'what' system analyses local features in the actual foveation as in Rybak et al. But, in our case, the 'where' memory, instead of programming a behavioural scanpath, scores the spatial relationship between successive fixation and the spatial relationship between the associated main edges. The recognition is based on the identification of parts and their spatial relationship. This gives the learning and recognition mechanisms more flexibility in the sense that, for recognising an object, several different fixation sequences may be accepted.     

Nonhomogeneous resolution of images of natural scenes

The aim of this research is to model and simulate the loss of visual resolution as a function of retinal eccentricity in the perception of natural scenes. The model of visual resolution is based on a space-variant low-pass filter, having a variable convolution kernel according to retinal eccentricity. The parameters of the model are computed from psychophysical measures of visual acuity as a function of retinal eccentricity. The implementation of the model allowed us to generate images of scenes with nonhomogeneous space-variant resolution, simulating the filtering executed by the eye. These scenes are used to test and optimise the model by means of experiments in static vision (through tachistoscopic presentations) and in dynamic vision where the resolution of the scene is computed, in real-time, as a function of the location of gaze.     

Development of object permanence in food-storing magpies (Pica pica)

The development of object permanence was investigated in black-billed magpies (Pica pica), a food-storing passerine bird. The authors tested the hypothesis that food-storing development should be correlated with object-permanence development and that specific stages of object permanence should be achieved before magpies become independent. As predicted, Piagetian Stages 4 and 5 were reached before independence was achieved, and the ability to represent a fully hidden object (Piagetian Stage 4) emerged by the age when magpies begin to retrieve food. Contrary to psittacine birds and humans, but as in dogs and cats, no "A-not-B error" occurred. Although magpies also mastered 5 of 6 invisible displacement tasks, evidence of Piagetian Stage 6 competence was ambiguous.     

Memorizing while walking: increase in dual-task costs from young adulthood to old age

The dual task of memorizing word lists while walking was predicted to become more difficult with age because balance and gait are in greater need of "attentional resources." Forty-seven young (ages 20-30 years), 45 middle-aged (40-50), and 48 old (60-70) adults were trained to criterion in a mnemonic technique and instructed to walk quickly and accurately on 2 narrow tracks of different path complexity. Then. participants encoded the word lists while sitting, standing, or walking on either track; likewise, speed and accuracy of walking performance were assessed with and without concurrent memory encoding. Dual-task costs increased with age in both domains; relative to young adults, the effect size of the overall increase was 0.98 standard deviation units for middle-aged and 1.47 standard deviation units for old adults. It is argued that sensory and motor aspects of behavior are increasingly in need of cognitive control with advancing age.     

Validation of a brief measure of posttraumatic stress disorder: the Distressing Event Questionnaire (DEQ)

The Distressing Event Questionnaire (DEQ) is a brief instrument for assessing posttraumatic stress disorder (PTSD) according to criteria provided in Diagnostic and Statistical Manual of Mental Disorders (4th ed.). The DEQ possesses high internal consistency and exhibited satisfactory short-term temporal stability in studies with Vietnam War combat veterans and battered women. In a sample of Vietnam War veterans and 4 separate samples of abused women (with histories of incest, rape, intimate partner abuse, or prostitution and abuse), the DEQ exhibited very good discriminative validity when judged against structured interview assessment of PTSD. The DEQ exhibited strong convergent validity with other PTSD measures and other indexes of adjustment and also exhibited strong convergent validity as a measure of PTSD across ethnic groups in both the veteran sample and the combined women's sample.     

Writer's cramp: A behavioural approach

The history of the treatment of writer's cramp by behaviour therapy is reviewed, and the theoretical assumptions underlying aversive treatment are criticized. The natural history of the disorder is reviewed, including the author's recent research in Student Health Centres. Some special observations are made on the disorder's peculiarities of incidence, both with regard to age of onset and the ethnic or geographical origins of what appears to be a significant minority of patients. Three approaches to studying aetiology are discussed, the neurological, psychopathological and the learning theory of orientations. Some suggestions are offered for further research embracing both experimental psychology and neurological investigation.     

Reviews of current books

Pastoral Psychology -     

The value of a liberal education: An essay on the power of knowing

Conclusion It is not easy to summarize what has been suggested in this essay. But in greatly simplified terms, something like this may serve.The understanding which comes through education increases the power of man over himself and his world; it increases his awareness, his capacity to influence, to accept and to enjoy. Everybody knows these things, but an explanation of how this power arises has been attempted. To do this, understanding, was said to be a process, a dynamic act, and four perspectives on this act, each showing one of the ways in which power is created have been presented.First, it was suggested that thought is the process of discriminating the field of feeling. This implies a much closer connection between thought and feeling than is ordinarily held. The particular power here is expressed in terms of the idea that the form of thought both expresses and limits at the same time. Due to this you get clear elements not only expressed in their own right, but deriving part of their clarity and individuality because of their explicit exclusion from other elements of the same field. Second, the power of knowing was explained as due to the tension between levels of significance It was suggested that concepts are fields of meaning composed of mutually constituting levels or particularity and generality.Third, it was suggested that the power of knowing comes through the extension of the range of significant feeling through the use of imagination.Finally, the double aspect of consciousness, which allows man both to do something consciously and to guide such doing self-consciously, was indicated as of major importance to the power and practice of a liberal education because it constitutes the power which frees man from himself.No one can liberate another person by organizing his experience for him. That he must do for himself; it is his life. But educators are in the business of disciplining the student in the truly human fashion which includes the organization of our experience in terms of dynamically interacting levels of generality and significance, the objectifying and clarifying of the field of feeling through thought, the broadening and deepening of that range of feeling through the imaginative projection of possibilities for feeling, as well as the steady consciousness of self that frees man from himself.These four aspects constitute the power which man's nature gives to him alone. It is because of this power that man has been called a rational animal. And along side of this power any others which he may be said to possess are as nothing. Indeed, it is open to question whether there are any other separate powers. Someone may want to mention the power of human love, but a moment of reflection should show that all we consider of most value in human love is an expression of the powers of which we have spoken. A liberal education is of value precisely because it is aimed at the development of those qualities of truly human activity which characterize man at his best. We may have to accept something less than this due to human frailty, but we need not be content to aim at anything less.     

Ministry to the chronic hemodialysis patient

The beginning point of ministry to those persons suffering from renal failure and turning to hemodialysis in order to sustain life is a sensitive understanding of the total dialysis experience. The minister or chaplain who visits a hemodialysis unit only occasionally will be more effective in bringing his skills to the task by understanding the unique dynamics of the physical, emotional and spiritual adjustment of those who depend on this relatively new therapy. The specific elements of this ministry in terms of those closely involved, professional care givers, families, and patients, are discussed with attention to the factors that tend to make ministry to the hemodialysis patient unique.This article is the result of a one-year chaplain residency at the Veterans Administration Hospital in Nashville, Tennessee, in partial fulfillment of clinical requirements for the D. Min. degree in Pastoral Theology and Counseling at the Divinity School, Vanderbilt University, Nashville, Tennessee.