A comparison of masking by visual and transcranial magnetic stimulation: implications for the study of conscious and unconscious visual processing

Visual stimuli as well as transcranial magnetic stimulation (TMS) can be used: (1) to suppress the visibility of a target and (2) to recover the visibility of a target that has been suppressed by another mask. Both types of stimulation thus provide useful methods for studying the microgenesis of object perception. We first review evidence of similarities between the processes by which a TMS mask and a visual mask can either suppress the visibility of targets or recover such suppressed visibility. However, we then also point out a significant difference that has important implications for the study of the time course of unconscious and conscious visual information processing and for theoretical accounts of the processes involved. We present evidence and arguments showing: (a) that visual masking techniques, by revealing more detailed aspects of target masking and target recovery, support a theoretical approach to visual masking and visual perception that must take into account activities in two separate neural channels or processing streams and, as a corollary, (b) that at the current stage of methodological sophistication visual masks, by acting in more highly specifiable ways on these pathways, provide information about the microgenesis of form perception not available with TMS masks.     

Dangerous and severe personality disorders: a new personality concept from the United Kingdom

In 1998, we in England were shocked by the apparently motiveless murders of a mother and two of her children when they were traveling home from school in a rural area. Subsequently a patient with personality disorder, being monitored by the forensic psychiatric services, was convicted of their murders. The government was determined to prevent this type of offense from recurring and in 1999 introduced a new concept, dangerous and severe personality disorder (DSPD). This subsequently became a treatment and assessment program for individuals who satisfy three requirements: (1) have a severe disorder of personality, (2) present a significant risk of causing serious physical or psychological harm from which the victim would find it difficult or impossible to recover, and (3) the risk of offending should be functionally linked to the personality disorder. The implications of this program are discussed with regard to international systems of classification and service provision. We also attempt to place DSPD in the wider context of psychiatric participation in the management of personality disordered offenders.     

Components of reflexive visual orienting to moving objects

Posner and Cohen (1984) and Maylor (1985) initially observed that a luminance change produces both facilitatory and inhibitory effects on subsequent detection. While Posner and Cohen claimed that the facilitatory effect was mapped in retinotopic coordinates, they showed that inhibition of return (IOR) was mapped in “environmental coordinates.” Tipper and colleagues (Tipper, Driver, & Weaver, 1991; Tipper et al., 1997; Tipper, Weaver, Jerreat, & Burak, 1994) and Abrams and Dobkin (1994b) have recently reported that IOR can be object based, but contradictory results have also been reported (Muller & von Mühlenen, 1996). Here we report six experiments showing that an uninformative peripheral cue can generate either facilitatory or inhibitory object-based effects that can tag moving objects and that can persist for several hundred milliseconds. Although the boundary conditions determining which effect will be manifest remain to be defined, the present results suggest that facilitation and inhibition are generated independently, rather than being components of the same biphasic process.     

Computational evidence for the foundations of numerical competence

INFANT is a computational model of Simon's (1997) ‘non-numerical’ account of the foundations of numerical competence. It operationalizes the memory, individuation, object permanence and spatiotemporal representation competencies of that account into a simulation of the Simon, Hespos & Rochat (1995) study. Results demonstrate that infants’ responses can indeed be reproduced without numerical representations.     

INCREASED PEER-TEACHING WITH GROUP-ORIENTED CONTINGENCIES FOR ARITHMETIC PERFORMANCE IN BEHAVIOR-DISORDERED ADOLESCENTS1

Group-oriented contingencies were applied to increase the arithmetic problem-solving rates of four behavior-disordered adolescent residents in a psychiatric hospital. The experiment followed an ABAC reversal design consisting of baseline conditions (A₁ and A₂), and cumulative (B) and mixed (C) interdependent group-oriented contingency conditions. Under the cumulative arrangement, the subjects earned five cents for every correctly solved multiplication problem. The same conditions were in effect with the mixed contingency, except that each subject was required to work at least three problems before any subject could earn money. The results indicated consistent increases in the subjects' arithmetic computation rates as a function of the group-oriented contingencies. Concurrent observations were made across the four conditions of the experiment on four categories of the subjects' verbalizations: antecedent peer-teaching, consequent peer-teaching, positive statements, and negative statements. The subjects' rates of antecedent peer-teaching verbalizations covaried with the group-contingency-induced increases in their levels of computation behavior. The majority of the verbalization involved answers to number fact questions or redirecting peers to engage in on-task activities. The three other categories of the subjects' verbalizations that were observed—consequent peer-teaching, positive statements, and negative statements—were not found to covary with the subjects' altered rates of computation behavior.     

Automated theorem proving for Łukasiewicz logics

This paper is concerned with decision proceedures for the ₀-valued ukasiewicz logics,. It is shown how linear algebra can be used to construct an automated theorem checker. Two decision proceedures are described which depend on a linear programming package. An algorithm is given for the verification of consequence relations in, and a connection is made between theorem checking in two-valued logic and theorem checking in which implies that determing of a -free formula whether it takes the value one is NP-complete problem.     

Stress,healthiness and health behaviours: An exploration of the role of life events,daily hassles,cognitive appraisal and the coping process

In a study of 220 participants, the relationship between life events, daily hassles, cognitive appraisal and coping, stress and general healthiness was investigated utilizing a self report methodology. The different aspects of healthiness and health behaviour/lifestyle appear to be related to different appraisal and coping styles. The role of daily hassles and life events in the process also vary across different aspects of health, illness and health behaviours. In fact the number of life events experienced appear to contribute more to hardiness than to vulnerability. It is proposed that to understand the process an integrative model is required which allows for flexibility in analysis.