The visual light field

Human observers are sensitive to the '(physical) light field' in the sense that they have expectations of how a given object would appear if it were introduced in the scene in front of them at some arbitrary location. Thus the 'visual light field' is defined even in the 'empty space' between objects. In that sense the light field is akin to visual space considered as a 'container'. The visual light field at any given point can be measured in psychophysical experiments through the introduction of a suitable 'gauge object' at that position and letting the observer adjust the appearance of that gauge object (eg through suitable computer rendering) so as to produce a 'visual fit' into the scene. The parameters of the rendering will then be considered as the measurement result. We introduced white spheres as gauge objects at various locations in stereoscopically presented photographic scenes. We measured the direction ('direction of the light'), diffuseness ('quality of the light' as used by photographers and interior decorators), and intensity of the light field. We used three very different scenes, with very different physical light fields. The images were geometrically and photometrically calibrated, so we were in a position to correlate the observations with the physical 'ground truth'. We report that human observers are quite sensitive to various parameters of the physical light field and generally arrive at close to veridical settings, although a number of comparatively minor systematic deviations from veridicality can be noted. We conclude that the visual light field is an entity whose existence is at least as well defined as that of visual space, despite the fact that the visual light field hardly appears as prominently in vision science as it does in the visual arts.     

Sequential resolution of fragmented visual percepts: experimental investigation of a subject's perceptual experience after a right medial temporal stroke

This report concerns the fragmented visual percepts in a woman, TR, following a right entorhinal-perirhinal infarct. In a previous report, Weddell [Weddell, R. A. (2005). A visual disorder producing highly selective deletion of recurring letters. Cortex, 41, 471-485] linked TR's highly selective tendency to delete recurrent letters with her fragmented percepts. The conflation of same-identity form elements was attributed to anterior extrastriate damage, which reduced the amount of information sustainable in fully resolved visual percepts, and the present experimental investigation of her subjective account of segment formation and resolution completes the story. She said that complex objects and long words first appeared as blurred regions, which sometimes included form elements. It is argued that figure-centred attentional mechanisms subdivided this blurred region into up to 3-4 parts. String length, lexical status (word vs. nonword), and background colour and/or luminance determined fragment length. Two rules described the fragment resolution sequence: largest segments usually resolved first, left-to-right resolution accounting for a few sequences. This resolution sequence occurred when stimuli were exposed too briefly for saccadic exploration, implicating endogenous attentional shifts. Experiment 4 confirmed TR's assertion that spatial, orthographic, and phonological information were stored during the fragment resolution process. Moreover, TR exerted considerable voluntarily control over the fragment resolution sequence and some influence over fragment length. Finally, these findings were interpreted in terms of an extended version of a neural network model of vision largely derived from nonhuman primate studies.     

Experiencing education in the new Christian schools in the United Kingdom: listening to the male graduates

The new independent Christian schools developed by parents and evangelical churches in the United Kingdom since the late 1960s remain controversial among both Christian and secular educators. In response to this controversy, the present study traced 106 men who had graduated from these schools between 1985 and 2003 and analysed their evaluation of the education they had received in these schools within four main themes: the quality of the education, the context of Christian and moral nurture, the quality of relationships (among the pupils, with the teachers and with the wider world) and preparation received for life after leaving school. Although there were some issues of criticism, the balance of opinion among the former pupils within all four areas was generally supportive of the new independent Christian schools, which were generally perceived as having prepared them well for life.     

A Pilot Study to Assess the Feasibility of a Multicenter Cluster Randomized Trial for the Management of Asymptomatic Persons with a Thrombophilia

There is controversy whether asymptomatic first-degree relatives (FDRs) of patients with venous thromboembolism (VTE) and thrombophilia should be screened, followed, and prescribed prophylaxis during risk periods. We recruited consecutive probands with idiopathic VTE and thrombophilia from our thrombosis clinics. Those FDRs with thrombophilia were randomized in family clusters to receive one-time verbal counseling and no organized follow-up or counseling, educational material, reminder aids and follow-up. Only 203 of 1,129 FDRs were eligible and consented. Dropouts were common; 1 FDR (1.7%) developed VTE. VTE risk, ability to treat and prevent were underestimated by the participants. Patients with VTE and thrombophilia and their FDRs are often not interested in thrombophilia testing. Despite education to inform their knowledge, interest and follow-up were less than ideal. The question of the best educational approach in these patients remains unanswered. The value of testing and following asymptomatic carriers of probands with VTE and thrombophilia remains unknown.     

Examination of individual differences in participation in outplacement program activities after a job loss

This study investigated the relationship among age, gender, and race relative to participation in self‐awareness, action‐oriented, and training activities after a job loss. The 156 respondents in this study were part of a larger, longitudinal study that collected data using questionnaires from outplacement program participants at 6 months and at 1 year following a company closing. Main effects were found for gender and for Age × Employment status. Implications of the study for outplacement programs, along with study limitations and future research directions, are discussed.     

Sex differences in levels of tolerance and attribution of blame for sexual harassment on a university campus

Although the issue of sexual harassment on college campuses has been discussed in the literature for the last five years, little attention has been paid to sex differences in levels of tolerance and attribution of blame in harassment. The current survey, based on a random sample of faculty, students, and staff at a large southern university, details sex differences in definitions of harassment, in attitudes toward causes, in attitudes toward romantic relationships between faculty and students, and in attitudes toward university policy. The authors suggest that sex differences reflect differing perceptions by men and women of their own self-interests within the university, and the organizational environment. Attention is also directed to the explanatory power of attribution theory.     

Difficulties and patterns of social support of mature college students in Hong Kong: Implications for student guidance and counselling services

The extent and nature of the difficulties faced by mature college students in a university in Hong Kong were examined. Who provided which types of support in which aspects of the lives of mature students was investigated. The results showed that time constraints were a major concern of many such students. Differences were found in the problems experienced in different modes of study and with different marital statuses. Spouses were support generalists who provided all types of support to their mature student partners, while lovers, friends and family members were support specialists who provided specific types of social support. The findings lend support to the hypothesis that the more sufficient the perceived social support received by mature students, the less the degree of difficulty they experience in their lives. Implications for service approach and for the provision of services are discussed, and recommendations on how to improve services are made.     

Effects of Environmental Uncertainty and Social Value Orientation in Resource Dilemmas

This study investigated the relationship between environmental uncertainty and social value orientation in a replenishable resource dilemma paradigm. One hundred seventy-two undergraduates harvested units from a common resource pool over 20 trials. Two levels of social value orientation (cooperative, noncooperative) were crossed with two levels of replenishment rate uncertainty (low, high). As predicted, noncooperators harvested significantly more resources than cooperators and high uncertainty subjects harvested more resources than low uncertainty subjects. The primary finding was the hypothesized three-way interaction among social value orientation, environmental uncertainty, and trials: Social value orientation moderated harvest decisionsonlyunder conditions of high uncertainty during the middle series of harvest trials. Noncooperators increased their harvests during this period, while cooperators harvested less and held their harvests constant across these trials. These results demonstrate that systematic individual differences exist in decision makers' responses to high environmental uncertainty. We suggest that social value orientation may exert its effect by influencing the scanning and processing of goal-relevant cues in this decision environment.     

Reading skill and the use of orthographic knowledge by Mature Readers

Summary Butler and Hains (1979) found individual differences in the effect of word length on RT in word naming and lexical-decision tasks; subjects scoring high on a vocabulary test were much less affected by word length than subjects with low scores. The present study attempted to determine whether such differences could be due to differences in the use of intraword structure, since word recognition has been linked, both empirically (Mason, 1978; Scheerer-Neumann, 1981) and theoretically (Mewhort & Campbell, 1981) to the use of orthographic redundancy. In Experiment 1, subjects were shown tachistoscopically presented letter strings varying in approximation to English. High vocabulary subjects were more capable of capitalizing on the redundancy with the higher-order approximations. Experiment 2 then established that performance on the vocabulary test was correlated with reading skill, measured by the Nelson-Denny Reading Test, and that skilled readers were more sensitive to the syllable structure in words. In the experiment, subjects were shown eight-letter words presented as three separate word units which either matched or violated syllable boundaries in the word. Skilled readers were more sensitive to the difference between syllable and nonsyllable units than were less skilled readers. The results obtained by Butler and Hains appear to reflect differences in reading skill and the efficiency of letter sequence parsing prior to word recognition.     

Converting an electronic calculator into a combination stopwatch-calculator

A method for adding electronic stopwatch capabilities to a calculator is described. An integrated circuit (NE555) is used for a time base. The circuit drives an opto-isolator or light-emitting diode that operates a photocell. The opto-isolator or photocell substitutes for a switch closure to increment the calculator in .10-sec intervals.