Cocaine addiction and personality: A mathematical model

The existence of a close relation between personality and drug consumption is recognized, but the corresponding causal connection is not well known. Neither is it well known whether personality exercises an influence predominantly at the beginning and development of addiction, nor whether drug consumption produces changes in personality. This paper presents a dynamic mathematical model of personality and addiction based on the unique personality trait theory (UPTT) and the general modelling methodology. This model attempts to integrate personality, the acute effect of drugs, and addiction. The UPTT states the existence of a unique trait of personality called extraversion, understood as a dimension that ranges from impulsive behaviour and sensation‐seeking (extravert pole) to fearful and anxious behaviour (introvert pole). As a consequence of drug consumption, the model provides the main patterns of extraversion dynamics through a system of five coupled differential equations. It combines genetic extraversion, as a steady state, and dynamic extraversion in a unique variable measured on the hedonic scale. The dynamics of this variable describes the effects of stimulant drugs on a short‐term time scale (typical of the acute effect); while its mean time value describes the effects of stimulant drugs on a long‐term time scale (typical of the addiction effect). This understanding may help to develop programmes of prevention and intervention in drug misuse.     

Expressed emotion and sociocultural moderation in the course of schizophrenia

This study examined whether the sociocultural context moderates the relationship between families' expressed emotion (EE) and clinical outcomes in schizophrenia. In a sample of 60 Mexican American caregivers and their ill relatives, we first assessed whether EE and its indices (criticism, emotional overinvolvement [EOI], and warmth) related to relapse. Second, we extended the analysis of EE and its indices to a longitudinal assessment of symptomatology. Last, we tested whether bidimensional acculturation moderated the relationship between EE (and its indices) and both relapse and symptom trajectory over time. Results indicated that EOI was associated with increased relapse and that criticism was associated with increased symptomatology. Additionally, as patients' Mexican enculturation (Spanish language and media involvement) decreased, EE was increasingly related to relapse. For symptomatology, as patients' U.S. acculturation (English language and media involvement) increased, EE was associated with increased symptoms longitudinally. Our results replicate and extend past research on how culture might shape the way family factors relate to the course of schizophrenia.     

INCREASING THE VARIETY OF FOODS CONSUMED BY A PICKY EATER: GENERALIZATION OF EFFECTS ACROSS CAREGIVERS AND SETTINGS

A multiple baseline across settings was used to evaluate the effects of differential reinforcement of alternative behavior, nonremoval of the fork ( Hoch, Babbitt, Coe, Krell, & Hackbert, 1994 ), and stimulus fading on consumption of food rejected previously. The study was conducted in two separate settings, and caregivers were trained in the intervention technique to increase generalization to natural settings. Food variety increased in both settings.     

the 2007 california citrus freeze: vulnerability,poverty, and unemployment issues of farmworkers

In January of 2007, freezing temperatures destroyed citrus and vegetable crops in California. By May 2007, more than 9,000 freeze‐related unemployment applications had been filed. Through face‐to‐face interviews, this study documents the experience of 63 farmworkers to find out how they survived the freeze and accessed services. Findings revealed that more than half of the interviewees did not seek benefits from the governmental One‐Stop centers set up to help them. Less than 10% of interviewees stated the benefits had covered their needs. Creating simple, nonbureaucratic guidelines for assisting affected individuals emerged as a need.     

On quoting the empty expression

Roy Sorensen has argued that a certain technical use of quotation marks to name the empty string supports a revised version of Davidson’s theory of quotation. I point out that Sorensen’s considerations provide no support for Davidson’s original theory, and I show that at best they support the revised Davidsonian theory only to the same extent that they support a simpler revised version of a Tarskian theory.     

Cognitive biases and decision making in gambling

Heuristics and cognitive biases can occur in reasoning and decision making. Some of them are very common in gamblers (illusion of control, representativeness, availability, etc.). Structural characteristics and functioning of games of chance favor the appearance of these biases. Two experiments were conducted with nonpathological gamblers. The first experiment was a game of dice with wagers. In the second experiment, the participants played two bingo games. Specific rules of the games favored the appearance of cognitive bias (illusion of control) and heuristics (representativeness and availability) and influence on the bets. Results and implications for gambling are discussed.     

Ambiguity aversion: the explanatory power of indeterminate probabilities

Daniel Ellsberg presented in Ellsberg (The Quarterly Journal of Economics 75:643–669, 1961) various examples questioning the thesis that decision making under uncertainty can be reduced to decision making under risk. These examples constitute one of the main challenges to the received view on the foundations of decision theory offered by Leonard Savage in Savage (1972). Craig Fox and Amos Tversky have, nevertheless, offered an indirect defense of Savage. They provided in Fox and Tversky (1995) an explanation of Ellsberg’s two-color problem in terms of a psychological effect: ambiguity aversion. The ‘comparative ignorance’ hypothesis articulates how this effect works and explains why it is important to an understanding of the typical pattern of responses associated with Ellsberg’s two-color problem. In the first part of this article we challenge Fox and Tversky’s explanation. We present first an experiment that extends Ellsberg’s two-color problem where certain predictions of the comparative ignorance hypothesis are not confirmed. In addition the hypothesis seems unable to explain how the subjects resolve trade-offs between security and expected pay-off when vagueness is present. Ellsberg offered an explanation of the typical behavior elicited by his examples in terms of these trade-offs and in section three we offer a model of Ellsberg’s trade-offs. The model takes seriously the role of imprecise probabilities in explaining Ellsberg’s phenomenon. The so-called three-color problem was also considered in Fox and Tversky (1995). We argue that Fox and Tversky’s analysis of this case breaks a symmetry with their analysis of the two-color problem. We propose a unified treatment of both problems and we present a experiment that confirms our hypothesis.     

Non-standard Stochastics with a First Order Algebraization

Internal sets and the Boolean algebras of the collection of the internal sets are of central importance in non-standard analysis. Boolean algebras are the algebraization of propositional logic while the logic applied in non-standard analysis (in non-standard stochastics) is the first order or the higher order logic (type theory). We present here a first order logic algebraization for the collection of internal sets rather than the Boolean one. Further, we define an unusual probability on this algebraization.     

Structural relaxation and rejuvenation in a metallic glass induced by shot-peening

The metallic glass Pd₄₀Cu₃₀Ni₁₀P₂₀ in as-cast or pre-annealed states was shot-peened successively at room temperature or at 77 K. The structural state of the glass was characterized by the relaxation spectrum measured in a differential scanning calorimeter. Mechanically induced relaxation of the as-cast glass and mechanically induced rejuvenation of pre-annealed samples are both more evident at 77 K than at 298 K, enabling deductions about the underlying mechanisms. The relaxation spectrum of the glass as a function of temperature displays two broad maxima, which occurring at the higher temperature is attributed to the part of the free-volume distribution associated with flow defects. In samples shot-peened at 77 K, the stored energy after deformation can be as high as 20% of the cold work. Shot-peening simultaneously generates flow defects within shear bands and destroys them in the matrix between bands: whose effect dominates is principally dependent on the initial state of relaxation of the glass. Shot-peening of partially crystallized samples appears capable of breaking up and dispersing crystallites without inducing any further significant crystallization.     

Are You Really Happy? Children’s Understanding of Real vs. Pretend Emotions

This paper studies children’s capacity to understand that the emotions displayed in pretend play contexts do not necessarily correspond to internal emotions, and that pretend emotions may create false beliefs in an observer. A new approach is taken by asking children about pretend emotions in terms of pretence-reality instead of appearance-reality. A total of 37 four-year-olds and 33 six-year-olds were asked to participate in tasks where they had to pretend an emotion or where they were told stories in which the protagonists pretended an emotion. In each task children were asked: a) if the pretend emotion was real or just pretended and b) if an observer would think that the emotional expression was real or just pretended. Results showed that four-year-olds are capable of understanding that pretend emotions are not necessarily real. Overall, six-year-olds performed better than younger children. Furthermore, both age groups showed difficulty in understanding that pretend emotions might unintentionally mislead an observer. Results are discussed in relation to previous research on children’s ability to understand pretend play and the emotional appearance-reality distinction.