Capturing lightness between contours

Homogeneously coloured bars may exhibit lightness differences at the intersections. A well-known example is the Hermann grid illusion, where crossing white bars on a black background show dark patches at the crossings. Jung (1973, Handbook of Sensory Physiology volume VII/3, pp 1-152) found that the dark patches persist when thin outlines are drawn at the intersections, and are even visible in foveal vision. Recently, it has been shown that making distortions to the contours of a Hermann grid-like configuration results in the disappearance of the illusory dark spots (Geier et al, 2008 Perception 37 651 665). We show that thin outlines at the crossings of the distorted Hermann grid induce lightness differences in the same direction as in the original Hermann grid illusion, even in foveal vision and in displays consisting of two crossing bars. Our experiments reveal that the induced lightness differences are independent of the luminance polarity and shape of the contours at the intersection. We suggest that the effect results from lateral inhibition and an additional spreading and capturing of these differences between luminance contours. A similar capturing between collinear contours may play a role in peripheral vision in the original Hermann grid.     

At first glance, transparency enhances assimilation

We investigated the role of transparency, perceptual grouping, and presentation time on perceived lightness. Both transparency and perceptual grouping have been found to result in assimilation effects, but only for ambiguous stimulus displays and with specific attentional instructions. By varying the presentation times of displays with two partly overlapping transparent E-shaped objects, we measured assimilation in unambiguous stimulus displays and without specific attentional instructions. The task was to judge which of two simultaneously presented E-shaped objects was darker. With unrestrained presentation times, if a transparency interpretation was possible, assimilation was not found. Inhibiting a transparency interpretation by occluding the local junctions between the two E-shaped objects, did lead to assimilation. With short presentation times, if a transparency interpretation was possible, assimilation was now also found. Thus, we conclude that, although transparency appears to enhance assimilation, with unambiguous stimulus displays and without specific attentional instructions, perceptual grouping is more important for assimilation to occur.     

On the relations between action planning, object identification, and motor representations of observed actions and objects

Recent evidence suggests that viewing a static prime object (a hand grasp), can activate action representations that affect the subsequent identification of graspable target objects. The present study explored whether stronger effects on target object identification would occur when the prime object (a hand grasp) was made more action-rich and dynamic. Of additional interest was whether this type of action prime would affect the generation of motor activity normally elicited by the target object. Three experiments demonstrated that grasp observation improved the identification of grasp-congruent target objects relative to grasp-incongruent target objects. We argue from this data that identifying a graspable object includes the processing of its action-related attributes. In addition, grasp observation was shown to influence the motor activity elicited by the target object, demonstrating interplay between action-based and object-based motor coding.     

On the dimensionality of the Dispositional Hope Scale

The Dispositional Hope Scale (DHS; C. R. Snyder et al., 1991) consists of two subsets of items measuring Agency and Pathways. The authors used bifactor analysis to evaluate the dimensionality structure of the scale. Data from 676 persons (295 psychiatric patients, 112 delinquents, and 269 students) were analyzed. The authors conclude that although the Pathway items seem to explain some additional variance when the Hope scale variance is partionalized out, the DHS allows unidimensional measurement.     

Children's conceptions of Jesus

This paper presents findings from a recent study investigating young children's (aged 10–11) conceptions of Jesus in England. The overall picture revealed by the study is that whilst there was a general assent amongst pupils in our sample towards an ethical and humanistic conception of the historical Jesus, there was less of a consensus about those issues which previous research claims children find difficult to understand, namely: the divinity of Jesus; the miracles of Jesus; and Christian beliefs pertaining to Jesus' continued presence in people's lives today. The paper concludes by arguing that the variety of conceptions of Jesus which are encountered in religious education (RE) may be seen by children as a barrier to learning rather than an opportunity to grow in understanding and highlights the need for further research into the relationship between children's hermeneutical horizons and RE curriculum content.     

Building information systems as universalized locals

We report on our experiences in a participatory design project to develop ICTs in a hospital ward working with deliberate self-harm patients. This project involves the creation and constant re-creation of socio-technical ensembles that satisfy the various, changing and often contradictory and conflicting needs in this context. Such systems are shaped in locally meaningful ways but nevertheless reach beyond their immediate context to gain wider importance and to be integrated with the larger environment. currently working on a participatory design project developing IT systems for psychiatrists working in a toxicology ward of a large general hospital. His research focuses on the local co-production of technologies which he currently explores in a production management context. His research interests lie in the field of human factors and interactive systems design, particularly approaches to IT systems design and development, the relationships between work and technology, and inter-disciplinary approaches to the design of dependable computing systems. carrying out a number of ethnomethodologically informed studies in a variety of applications. He holds a Ph.D. in ethnomethodology from the University of Manchester and is currently involved in research on computer-aided prompting systems for radiological work. He has interests in ethnomethodology, CSCW, SSK and the philosophy of social sciences. where he convenes an interdisciplinary research programme on ‘the social shaping of technology’.     

A connectionist implementation of the theory of planned behavior: association of beliefs with exercise intention.

The theory of planned behavior suggests attitudes are a product of salient beliefs. This study examined whether aggregating salient beliefs was plausible within a more biologically centered information-processing environment. A neural network was used to examine associations among beliefs relating to exercise intention. Data on intentions and behavioral, normative, and control beliefs from 114 respondents were used to train (by error backpropagation) a neural network to associate beliefs with intention. The R-sup-2 between the network's estimated and self-reported intention was.66. The network's representation comprised 6 belief profiles associated with high, moderate, or low behavioral intention. The neural network accommodated complex relationships among beliefs and belief-intention associations and indicated how high-level constructs such as attitudes may be viewed as the best fit (compromise state) between aroused beliefs.     

Measuring clients' experience of careers guidance interviews: Exploratory studies

Initial findings of the development of a measure of client experience of the careers guidance interview are reported. Initially based on the Medical Interview Satisfaction Scale (Wolf et al., 1978), items were derived which sampled across affective, cognitive and behavioural components of careers interviewing. The scale is pilot tested on 60 15 and 16 year-old school pupils, of low academic potential and all of whom had experienced a careers interview with a careers officer. Initial results are only partially supportive of the findings of Wolf et al. (1978). Results of a further field study of the 20-item scale based on 54 careers interviews are also reported where factor analytic data are promising. The contribution of the scale in testing related hypotheses (e.g. met expectation hypothesis) is indicated.     

The definability of objective becoming in Minkowski spacetime

In his recent article On Relativity Theory and Openness of the Future (1991), Howard Stein proves not only that one can define an objective becoming relation in Minkowski spacetime, but that there is only one possible definition available if one accepts certain natural assumptions about what it is for becoming to occur and for it to be objective. Stein uses the definition supplied by his proof to refute an argument due to Rietdijk (1966, 1976), Putnam (1967) and Maxwell (1985, 1988) that Minkowski spacetime leaves no room for objective becoming whatsoever. However, Stein's proof does not seem to go far enough. By considering only what events have become from the standpoint of any given event, Stein's uniqueness proof fails from the outset to allow for a more general kind of becoming whereby it is understood to occur from the standpoint of events on the particular worldlines followed by observers. This suggests that there may, after all, be more than one way to define objective becoming in Minkowski spacetime once each observer's worldline is allowed to figure in the definition. This suspicion is further aroused by two recent proposals for objective, worldline-dependent becoming due to Peacock (1992) and Muller (1992) who advocate ways of defining becoming that are not equivalent to the definition Stein's uniqueness proof delivers. Nevertheless, we show that Stein's uniqueness proofcan be extended in a natural way to cover this more general kind of becoming, provided one does not enrich standard Minkowski spacetime by privileging certain sets of worldlines over others in an unwarranted manner. Thus we aim to reinforce Stein's point that standard Minkowski spacetime does make room for objective becoming, but in essentially only one way, despite arguments and proposals to the contrary.