Abstraction in Algorithmic Logic

We develop a functional abstraction principle for the type-free algorithmic logic introduced in our earlier work. Our approach is based on the standard combinators but is supplemented by the novel use of evaluation trees. Then we show that the abstraction principle leads to a Curry fixed point, a statement C that asserts C ⇒ A where A is any given statement. When A is false, such a C yields a paradoxical situation. As discussed in our earlier work, this situation leaves one no choice but to restrict the use of a certain class of implicational rules including modus ponens.     

Affect is a form of cognition: A neurobiological analysis

In this paper, we suggest that affect meets the traditional definition of "cognition" such that the affect-cognition distinction is phenomenological, rather than ontological. We review how the affect-cognition distinction is not respected in the human brain, and discuss the neural mechanisms by which affect influences sensory processing. As a result of this sensory modulation, affect performs several basic "cognitive" functions. Affect appears to be necessary for normal conscious experience, language fluency, and memory. Finally, we suggest that understanding the differences between affect and cognition will require systematic study of how the phenomenological distinction characterising the two comes about, and why such a distinction is functional.     

Costs in searching for two targets: dividing search across target types could improve airport security screening

The cost of searching for two visual targets simultaneously was compared against two separate single‐target searches using exposure time and accuracy measures within a staircase procedure. Dual‐target search for all stimuli (colour, shape and orientation) exhibited a loss of accuracy for one target. For orientation and shape, this dual‐target cost in accuracy was extreme, with chance‐level performance on one target. For colour, dual‐target search exhibited an additional cost in search time, with search requiring a longer exposure than the summed time required for two single‐target searches. An additional search‐time cost was also found for orientation targets when irrelevant colour variation was added to the display. In conclusion, dual‐target search for dissimilar targets is accompanied by an accuracy cost. Furthermore, colour variation, whether task‐relevant or not, leads to an additional cost in processing speed. The results suggest that a divided‐effort strategy would improve performance in search tasks such as X‐ray baggage screening. Copyright © 2006 John Wiley & Sons, Ltd.     

The role of the amygdala in visual awareness

Pessoa and colleagues recently reported the novel finding that objective awareness of a negative stimulus is associated with coactivation of the amygdala and fusiform gyrus. Based on the neuroanatomical connections of the amygdala, we suggest that the amygdala is acting to increase neural activity in the fusiform gyrus, thereby increasing the likelihood that visual representations that have affective value reach awareness. The psychological consequence is that a person's momentary affective state might help to select the contents of conscious experience.     

Verbal hallucinations in normals,I: People who hear ‘voices’

Two studies are reported that describe the phenomena of verbal hallucinations in the general population and test two explanations of those reports. Subjects were 198 male and 387 female college students who completed a verbal hallucination questionnaire plus one or more additional questionnaires. We found that a large minority reported hallucinations and that nearly half reported having them at least once a month. The present data indicated that these reports were not related to four measures of social conformity. Neither were they related to measures of overt, or incipient, symptoms of psychopathology. We have concluded that the majority of these reports are generally veridical accounts of conscious experience in normal individuals.     

Family process and child anxiety and aggression: An observational analysis

Barrett, Rapee, Dadds, and Ryan (1996) described a phenomenon whereby family discussions magnified the style of children's problem solving in a way characteristic of their particular clinical diagnosis. That is, anxious children became more avoidant, aggressive children more aggressive, and nonclinic children more prosocial, after discussing ambiguous hypothetical situations with their parents. This study examined specific sequences of communications exchanged between parents and children hypothesized to underlie this family exacerbation of child cognitive style. Family discussions were videotaped and categorized for groups of anxious, aggressive, and nonclinic children and their parents. Results revealed differences between groups of parents in frequency of agreeing with and listening to their child and the frequency of pointing out positive consequences. Conditional probability analyses showed that parents of anxious children were more likely to reciprocate avoidance, while parents of nonclinic children were more likely to agree with and listen to prosocial plans from their child. Differences in parent behaviors observed during the family discussions were reliably associated with the child's response to the ambiguous situation proposed after the family discussion. Results support a model of developmental anxiety and aggression that emphasizes the interaction of family processes and social-cognitive development in the child.This research was supported by grants from The National Health and Medical Research Council of Australia, The University of Queensland, and The Myer Foundation of Australia.     

Coping Strategies,Substance Use,Sexual Activity,and HIV Sexual Risks in a Sample of Gay Male STD Patients1

The relationships of coping strategies with levels of substance use and sexual activity, and with HIV sexual risks, are examined in a sample of gay male STD clinic patients (n = 416). Previous research has suggested that use of problem-focused coping strategies should be negatively related to levels of substance use, levels of sexual activity, and HIV sexual risks; use of emotion-focused coping strategies should be positively related to these outcomes. It is argued that substance use and sexual activity clearly fit within a coping perspective, but that the HIV sexual risks/coping relationship is less clear. In multivariate analysis, the problem-focused strategy of advice seeking is negatively related to the number of types of drugs used and to the number of sexual partners; the problem-focused strategy of support seeking is negatively related to the number of days using drugs; and the use of emotion-focused strategies is positively related to the number of types of drugs used. Problem-focused coping strategies are less directly related to engaging in HIV sexual risks when measures of substance use and of sexual activity are included in the prediction; emotion-focused coping strategies are more stably related to HIV risk. Indirect effects of coping on HIV risk are also identified through the effects of coping on the number of types of drugs used, number of sex partners, and number of times having sex. It is proposed that the relationships between coping and levels of substance use and sexual activity reflect the use of these activities as ways of relieving strain, but that relationships between coping and HIV sexual risks involve less clearly understood direct and indirect relationships.