Ignorance of the Own Past

It is shown that for an inside observer it is impossible to distinguish all states in which a system was at some past time. This holds for classical and quantum systems, but an assumption of determinism is essential in the proof.     

Listener: A tool for client-side investigation of hypermedia navigation behavior

Behavioral researchers have employed hypermedia-based software applications in their experiments for some time. More recently, interest in the World-Wide Web has developed among researchers in the social sciences, and popular use of this new medium continues to grow at an incredible rate. This paper describes Listener, a tool developed to log users’ hypermedia and World-Wide Web navigation behavior using Apple Macintosh computers in a laboratory setting. Listener is able to capture navigation actions through cached documents, overcoming some of the problems associated with analyzing standard web server logs.     

From Detachment to Immersion: Wittgenstein and 'The Problem of Life'

Wittgenstein is widely recognised as a philosopher with a markedly ethical character to his thought. This paper seeks to highlight the dimension of selflessness and renunciation in this ethical character. It also seeks to show that there are distinct differences in Wittgenstein's implicit conception of what an ethical selflessness amounts to in the early and the later periods. The concept of absolute safety enables us to appreciate the connections between the early Wittgenstein and a particular type of nineteenth-century obsession with a selflessness that combines with a self-sufficient capacity to stand aloof from anxiety in the face of the human condition involving meaninglessness and death. In the early Wittgenstein that aloofness came close to a solipsistic and, in some ways, self-affirming apartness from everything other than the self. In contrast, the ethical spirit that permeates Wittgenstein's later thought is imbued with a sense of the immersion of the self ultimately and absolutely 'in the world'. The sense in which this latter phrase is used is defined further in the paper.     

The right to refuse treatment: Paradox,pendulum and the quality of care

This clinical and theoretical overview of the right to refuse treatment will address some of the themes that have dominated this area of interface between psychiatry and the law, and have, perhaps, obscured the real concern of the right to refuse treatment question; i.e., the issue of quality of care. Central themes include factors present in the medicolegal context and recent events, origin of the concept of the right to treatment, the separation of confinement from treatment, and the changing models of vicarious decision making. This review also addresses judicial conceptualizations of treatment, including the concept of quarantine, judicial risk-aversiveness, and judicial fantasies of drug action. Some possible directions for the future are also examined.     

On the modularity of implicit sequence learning: independent acquisition of spatial, symbolic, and manual sequences

Learning sequential structures is of fundamental importance for a wide variety of human skills. While it has long been debated whether implicit sequence learning is perceptual or response-based, here we propose an alternative framework that cuts across this dichotomy and assumes that sequence learning rests on associative changes that can occur concurrently in distinct processing systems and support the parallel acquisition of multiple uncorrelated sequences. In three experiments we used a serial search task to test critical predictions of this framework. Experiments 1 and 2 showed that participants learnt uncorrelated sequences of auditory letters and manual responses, as well as sequences of visual letters, spatial locations, and manual responses simultaneously, as indicated by a reliable response time (RT) cost incurred by occasional deviants violating either of the sequences. This RT cost was reliable even when participants showing explicit knowledge were excluded. In Experiment 3 learning of spatial and nonspatial sequences was functionally dissociated: whereas a spatio-motor distractor task disrupted learning of location but not of letter sequences, a phonological distractor task had the reverse effect. The distractor tasks thus did not reduce unspecific attentional resources, but selectively disrupted the formation of sequential associations within spatial and nonspatial processing dimensions. These results support the view that implicit sequence learning rests on experience-dependent changes that can occur in parallel in multiple processing systems involved in spatial attention, object recognition, phonological processing, and manual response selection. The resulting dimension-specific sequence representations support independent predictions of what will appear next, where it will appear, and how one will have to respond to it.     

Construction and validation of the South African version of the Fear Survey Schedule for Children: an exploratory factor analysis

The Fear Survey Schedule for Children-Revised (Ollendick, 1983) is an 80-item self-report instrument that has been used internationally to asses the number of fears and general level of fearfulness among children. Despite its widespread use, this instrument has not been adapted to the South African context. The present study addressed this gap by means of a 2-phase investigation aimed at developing a South African version of the instrument. In Phase 1, semistructured interviews were conducted with 40 children (7 to 13 years of age). Qualitative data obtained from these interviews were used to construct additional items for inclusion in the South African Fear Survey Schedule for Children-Revised. The modified scale, consisting of 97 items, was then administered to a sample of 646 children between the ages of 7 and 13 years. Further psychometric considerations resulted in the final version of the scale consisting of 74 items with high internal consistency (α=.97). The factor structure was explored by means of principal component analysis with varimax rotation and a 5-factor solution was found to provide the best conceptual fit. The factors identified were as follows: Fear of Death and Danger; Fear of the Unknown; Fear of Small Animals and Minor Threats to Self; Large Animal Fears; and Situational Fears. Differences between the South African version and the original Fear Survey Schedule for Children-Revised are noted and implications for the study of fear in South Africa and other countries are discussed.