Discrete dynamic choice: An extension of the choice models of thurstone and luce

The present paper deals with the extension of two well-known static discrete choice theories to the dynamic situation in which individuals make choices at several points in (continuous) time. A dynamic version of Luce's Axiom, “independence from irrelevant alternatives”, is proposed and some of its implications are derived. In the static case Yellott (J. Math. Psych. 1977, 15, 109–146) and others have demonstrated that an independent random utility model generated from the extreme value distribution exp(?e^?ax?b) becomes equivalent to Luce's Axiom. Yellott also introduced an axiom called “invariance under uniform expansions of the choice set”, and he proved that within the class of random utility models with independent identically distributed utilities (apart from a location shift) this axiom is equivalent to Luce's Axiom. These results are extended to the dynamic situation and it is shown that if the utility processes are expressed by so-called extremal processes the corresponding choice model is Markovian. A nonstationary generalization is proposed which is a substantial interest in applications where the parameters of the choice process are influenced by previous choice experience or by time-varying exogenous variables. In particular, it is demonstrated that the nonstationary model is Markovian if and only if the joint choice probabilities at two points in time have a particular form. Thus, the paper provides a rationale for applying a specific class of Markov models as the point of departure when modelling mobility processes that involve individual discrete decisions over time.     

复杂胫骨平台骨折处理的临床决策

复杂胫骨平台骨折处理相当困难,治疗上存在着一系列矛盾,准确的骨折分型和软组织损伤情况评估,合理的手术入路和手术时机选择,重视复位、固定方式和方法及软组织保护,双下肢同时消毒包扎为术中快速的体位转换提供了方便,一系列临床决策极大地提高了复杂胫骨平台骨折的治疗水平。     

An analogue study of the effects of Psychological Debriefing on eyewitness memory

Sixty-one participants from the community participated in a randomised controlled trial of group debriefing to assess the effect of this intervention upon memory for a stressful event. Participants were randomly allocated to one of three groups: debriefing; debriefing with an experimenter confederate present (who supplied three pieces of misinformation to the group regarding the stressful event); and a no-treatment control. All groups were shown a very stressful video and were again reviewed after 1 month. Members of the debriefing group where a confederate provided misinformation were more likely to recall this misinformation as fact than members of the other two groups. The debriefing group was also more accurate in their recall of peripheral content than the confederate group. Across all groups, participants were found to be more accurate at central rather than peripheral recall yet more confident for incorrect memories of the video than correct memories.     

Working memory deficit in children with mathematical difficulties: a general or specific deficit?

This study examined whether children with mathematical difficulties (MDs) or comorbid mathematical and reading difficulties have a working memory deficit and whether the hypothesized working memory deficit includes the whole working memory system or only specific components. In the study, 31 10-year-olds with MDs and 37 10-year-olds with both mathematical and reading difficulties were compared with 47 age-matched and 50 younger controls (9-year-olds) on a number of working memory tasks. Compared with the age-matched controls, both groups of children with MDs performed worse on tasks tapping the central executive (e.g., visual matrix span) and the phonological loop (e.g., word span). More important, the MD group performed worse than the younger controls on the counting span task, whereas the group with comorbid mathematical and reading difficulties performed worse on the counting span task and the visual matrix span task. These findings provide support for the assumption that children with MDs have a working memory deficit. More specifically, children with MDs have a central executive deficit connected to concurrent processing and storage of numerical and visual information.     

International Migration and Religious Selection

Migrants are selected by several characteristics (age, education, skill, health, and family migration experience). Often less examined is religious selection. Using Guatemalan data, this research note tests whether religious affiliation is significantly associated with migration to the United States, net of other competing factors. Results are robust, demonstrating that Protestants are more likely than other religious groups to migrate. Additionally, mediating factors (social networks, cultural norms, and ideological links) are tested to identify social mechanisms behind the Protestant effect. The research note concludes with implications of religious selection and how religious selection can be further examined in migration and religion studies.     

Drive for muscularity and muscularity-oriented disordered eating in men: The role of set shifting difficulties and weak central coherence

Set shifting difficulties and weak central coherence are information-processing biases associated with thinness-oriented eating and body image pathology in women. However, little is known about the relationship between these processing biases and muscularity-oriented eating and body image pathology. We investigated whether set shifting and central coherence were uniquely related to the drive for muscularity and muscularity-oriented disordered eating in a sample of 91 male undergraduates. Participants completed the Wisconsin Card Sort Test, the Matching Familiar Figures Task, the Drive for Muscularity scale, and a modified Eating Disorders Examination-Questionnaire. Results indicated that set shifting difficulties and weak central coherence were both uniquely positively associated with the drive for muscularity, and that set shifting difficulties were uniquely positively associated with muscularity-oriented disordered eating. Results are discussed with regard to the male experience of body image and eating pathology, and in regard to muscle dysmorphia.     

Methodological Considerations in the Neuropsychological Study of Central Nervous System Underarousal with a Specific Emphasis on Coma

Several obstacles exist that impede the scientific study of pathological underarousal (stupor and coma). For instance, there is a lack of a clear, rational, standardized taxonomy with which to describe the phenomenon. Moreover, there is considerable confusion of the construct of arousal with other neurobehavioral constructs. The field also suffers from a general lack of acceptably reliable and valid instruments, especially measures of long-term outcome. Additionally, current treatments for chronic pathological underarousal are frequently presumptive and applied haphazardly, and thus do little to elucidate the process of recovery. It is suggested that biomedical and neuropsychological approaches to the study and treatment of pathological underarousal are complementary and that it is useful to view pathological underarousal as a behavioral, as well as a medical, phenomenon.