Satisfiability Decay along Conjunctions of Pseudo-Random Clauses

k-SAT is a fundamental constraint satisfaction problem. It involvesS(m), the satisfaction set of the conjunction of m clauses,each clause a disjunction of k literals. The problem has manytheoretical, algorithmic and practical aspects. When the clauses are chosen at random it is anticipated (butnot fully proven) that, as the density parameter m/n (n thenumber of variables) grows, the transition of S(m) to beingempty, is abrupt: It has a "sharp threshold", with probability1 – o(1). In this article we replace the random ensemble analysis by apseudo-random one: Derive the decay rule for individual sequencesof clauses, subject to combinatorial conditions, which in turnhold with probability 1 – o(1). This is carried out under the big relaxation that k is not constantbut k = log n , or even r log log n . Then the decay of S isslow, "near-perfect" (like a radioactive decay), which entailssharp thresholds for the transition-time of S below any givenlevel, down to S = .     

Principled and statistical connections in common sense conception

Nominal concepts represent things as tokens of types. We report six experiments that investigate the nature of the relations we represent between the type of thing something is (e.g. DOG) and its other properties. The experiments provide evidence that we represent principled connections between the type of thing something is (e.g. DOG) and some of its properties (k-properties; e.g. having four legs for dogs), but not other properties (t-properties; e.g. being brown for dogs). Principled connections are different from logical, statistical, and causal connections. Principled connections, (i) license the expectation that tokens of the type will generally possess the k-property, (ii) license explanation of the presence of k-properties in tokens of a type by reference to the type of thing it is, and (iii) license normative expectations concerning the presence of the k-property in tokens of the type. The experiments provide evidence for all three of these aspects of principled connections. The experiments also demonstrate that principled connections must be distinguished from merely strong statistical connections. We suggest that principled connections are one of the fundamental types of relations (in addition to logical, statistical, and causal relations) in terms of which our conceptual knowledge is structured. We argue that principled connections reveal a formal mode of understanding and explanation. This mode of understanding complements other modes of understanding that have been studied within the theory-based approach to conceptual representation. Finally, we suggest that kind representations are distinguished from representations of mere types by the representation of principled connections to k-properties.     

Reward magnitude effects on temporal discrimination

Changes in reward magnitude or value have been reported to produce effects on timing behavior, which have been attributed to changes in the speed of an internal pacemaker in some instances and to attentional factors in other cases. The present experiments therefore aimed to clarify the effects of reward magnitude on timing processes. In Experiment 1, rats were trained to discriminate a short (2 s) vs. a long (8 s) signal followed by testing with intermediate durations. Then, the reward on short or long trials was increased from 1 to 4 pellets in separate groups. Experiment 2 measured the effect of different reward magnitudes associated with the short vs. long signals throughout training. Finally, Experiment 3 controlled for satiety effects during the reward magnitude manipulation phase. A general flattening of the psychophysical function was evident in all three experiments, suggesting that unequal reward magnitudes may disrupt attention to duration.     

Chess as a Behavioral Model for Cognitive Skill Research: Review of Blindfold Chess by Eliot Hearst and John Knott

This multifaceted work on chess played without sight of the pieces is a sophisticated psychologist's examination of this topic and of chess skill in general, including a detailed and comprehensive historical account. This review builds on Hearst and Knott's assertion that chess can provide a uniquely useful model for research on several issues in the area of cognitive skill and imagery. A key issue is the relationship between viewing a stimulus and mental imagery in the light of blindfold chess masters' consistent reports that they do not use or have images. This review also proposes a methodology for measuring and quantifying an individual's skill shortfall from a theoretical maximum. This methodology, based on a 1951 proposal by Claude Shannon, is applicable to any choice situation in which all the available choices are known. The proposed “Proficiency” measure reflects the equivalent number of “yes—no” questions that would have been required to arrive at a best choice, considering also the time consumed. As the measure provides a valid and nonarbitrary way to compare different skills and the effects of different independent variables on a given skill, it may have a wide range of applications in cognitive skill research, skill training, and education.     

Monaural Loudness Adaptation for Middle-Intensity Middle-Frequency Signals: The Importance of Measurement Technique

Using the Simple Adaptation technique (SA) and the Ipsilateral Comparison Paradigm (ICP), the authors studied monaural loudness adaptation to a middle-intensity [60 dB(A)] tone at signal frequencies of 250, 1000, and 4000 Hz in the left and right ears. Adaptation effects were absent when the SA procedure was used. However, they were observed uniformly across all frequency values with the ICP, a result that challenges the assertion in the literature, on the basis of SA measures, that loudness adaptation for middle-intensity signals occurs only at frequencies above 4000 Hz. The ICP features periodic intensity modulations (±10 dB relative to the base signal) to accommodate listeners' needs for referents by which they can gauge subtle changes in the loudness of the adapting tone, a key component that is missing in the SA method. Adaptation effects in this investigation were similar in both ears, supporting the equal susceptibility assumption common in loudness adaptation studies.     

Social support and cardiovascular responding to laboratory stress: Moderating effects of gender role identification,sex, and type of support

The objective of the present study was to examine moderating effects of gender role identification, sex, and type of support on the buffering role of social support on cardiovascular responses. We hypothesized that (a) gender role identification, more than sex, would moderate the effect of social support and (b) to obtain optimal attenuating effects of social support, type of support provided should match type of support preferred in terms of one's gender role identification. That is, feminine participants would benefit more from relatively direct support, whereas masculine participants would benefit more from indirect support. Healthy participants (N = 100) performed a psychological stressor in the presence of a friend, after mental activation of a friend, or alone. Results revealed no moderating effects of gender role identification whether or not in combination with type of support. Nevertheless, results demonstrated an attenuating effect of mental support on heart rate and cardiac output in men. It is concluded that pathways linking social relationships and health may differ between women and men.     

Comparison of the role of self-efficacy and illness representations in relation to dietary self-care and diabetes distress in adolescents with type 1 diabetes

This cross-sectional study examined the joint effects of self-efficacy and illness representations on dietary self-care and diabetes distress in adolescents with type 1 diabetes by comparing two theoretical models: the Self-regulation Model (Leventhal, H., Meyer, D., & Nerenz, D. (1980). The common-sense representations of illness danger. In S. Rachman (Ed.), Medical Psychology (Vol. 2, pp. 7–30). New York: Pergamon.) and Social Cognitive Theory (Bandura, A. (1997). Self efficacy: The exercise of control. New York: W.H. Freeman.). One hundred and fifty-one adolescents with type 1 diabetes completed self-report measures of dietary self-efficacy, illness representations, dietary self-care and diabetes distress. Data were analysed using structural equation modelling. The model best supported by the data (Leventhal's Self-regulation Model) showed that dietary self-efficacy, perceived consequences and treatment effectiveness had direct and independent effects on both dietary self-care and diabetes distress. Together with dietary self-efficacy, perceived short-term treatment effectiveness was a significant predictor of dietary self-care. Age was found to be a negative predictor of short-term treatment effectiveness beliefs. Diabetes distress was best predicted by self-efficacy and perceived consequences. It can be concluded that to target effectively dietary self-care and distress, clinicians should focus on key illness representation variables (perceived short-term treatment effectiveness and perceived consequences) in conjunction with self-efficacy.     

exploring drug users' illness representations of hiv,hepatitis b and hepatitis c using repertory grids

Abstract

Hepatitis B and C viruses are more prevalent among injecting drug users than HIV. This study explored drug users' illness representations of hepatitis B and C using repertory grid methodology. Initially, nine drug users were presented with six elements including hepatitis B and C, and HIV. Constructs were elicited via the sequential form variation of the method of triads. Elements were rated on elicited constructs using a five-point scale, and analyzed using “Flexigrid”. In a second quantitative research stage, 52 drug users were presented with six elements and supplied constructs. Results of the first stage indicated participants were able to generate constructs relating to Leventhal et al.'s (1980) features of illness representations. Most constructs, however, were causal in nature. Participants perceived hepatitis B, C and HIV similarly along the causal component. This similarity on the causal component was largely replicated in the second research stage. Participants, however, distinguished HIV from hepatitis B and C along serious, cure and timeline features. Participants did not distinguish hepatitis B from hepatitis C. The implications of these results for health promotion are discussed.     

Multiple Attachment Representations in Clinical Practice: Case Study of a Six-Year-Old Maltreated Child

Research on attachment predominantly traces the effect of a single or primary attachment and/or attachment style on working models and behavior. However, most children form multiple attachments. This article reviews research on multiple attachment representations in children and considers how such information can usefully be applied to clinical settings. Through the case study of a six-year-old adopted boy with a history of maltreatment, it explores how those internal working models can be assessed in treatment and the clinical value of recognizing different attachment representations and styles. Implications for treatment interventions are explored.