On the possibility and desirability of constructing a neutral conception of disability

Disagreement about the properattitude toward disability proliferates. Yetlittle attention has been paid to an importantmeta-question, namely, whether ``disability' isan essentially contested concept. If so, recentdebates between bioethicists and the disabilitymovement leadership cannot be resolved. Inthis essay I identify some of the presumptionsthat make their encounters so contentious. Much more must happen, I argue, for anydiscussions about disability policy andpolitics to be productive. Progress depends onconstructing a neutral conception ofdisability, one that neither devaluesdisability nor implies that persons withdisabilities are inadequate. So, first, I clearaway the conceptual underbrush that makes usthink our idea of disability must bevalue-laden. Second, I sketch someconstituents of, and constraints upon, aneutral notion of disability. This revised version was published online in June 2006 with corrections to the Cover Date.     

对变化/分割模型的检验(Ⅱ)

在前一报告的基础上设计了两个实验,对变化／分割模型做进一步的检验,实验３控制目标时距和该时距内的填充数字系列的分割段数以及段的持续时间,操纵段内的项目数;结果显示,数字系列的分割段数明显影响延迟操作条件下的时距估计,而段内的项目数则不影响对时距的估计,实验４控制目标时距和该时距内填充数字系列的分割段数以及段内的项目数,操纵的持续时间,结果显示,对时距的估计取决于被试所傅物时间标尺,四个实验结果表明     

心理福利的结构研究

通过对幸福、福利及经济福利的反思 ,提出了心理福利这一研究课题 ;结合对被试样本的问卷调查 ,经因子分析 ,分别考察了心理福利的三个维度 :自我幸福感、生活满意感和对社会的行为性评价的因子结构 ;以此为基础 ,运用 L ISREL 8构建了心理福利的二阶结构模型。结果显示 ,模型与数据拟合良好。     

Choice, contingency discrimination, and foraging theory

Four pigeons were trained on eight or nine pairs of independent concurrent variable-interval schedules. The range of reinforcement ratios included extreme ratios (up to 532 to 1). Large samples of stable performance were gathered. Contrary to the findings of Davison and Jones (1995), the generalized matching law described choice more accurately than a contingency-discriminability model. Taking small samples (5 to 10 sessions) and applying a more liberal stability criterion used by Davison and Jones only increased the unsystematic variance in the data and in estimates of generalized-matching-law sensitivity. Because changing to dependent scheduling and inserting a changeover delay had no systematic effect, the deviations from generalized matching reported by Davison and Jones probably arose from imperfectly discriminated stimuli. Analysis of visits revealed that visits to the nonpreferred alternative were brief and approximately constant. When choice between the preferred (rich) and nonpreferred (lean) alternatives, regardless of position, was analyzed according to the generalized matching law, sensitivities approximated 1.0, with bias in favor of the lean alternative. This bias, which arose from an excessive frequency of visits to the lean alternative, explains undermatching as the result of fitting one line to a choice relation that consists of two displaced lines, both with a slope of 1.0. The pattern of deviation from the generalized matching line confirmed this account. The findings suggest an alternative analysis of choice that focuses on probability of visiting the lean alternative as the dependent variable. This probability was directly proportional to ratio of reinforcement. Matching, undermatching, and overmatching may all be explained by a view of concurrent performance based on foraging theory, in which responding occurs primarily at the rich alternative and is occasionally interrupted by brief visits to the lean alternative.     

How pigeons discriminate the relative frequency of events.

This study examined how pigeons discriminate the relative frequencies of events when the events occur serially. In a discrete-trials procedure, 6 pigeons were shown one light nf times and then another nl times. Next, they received food for choosing the light that had occurred the least number of times during the sample. At issue were (a) how the discrimination was related to two variables, the difference between the frequencies of the two lights, D = nf - nl, and the total number of lights in the sample, T = nf + nl; and (b) whether a simple mathematical model of the discrimination process could account for the data. In contrast with models that assume that pigeons count the stimulus lights, engage in mental arithmetic on numerons, or remember the number of stimuli, the present model assumed only that the influence of a sample stimulus on choice increases linearly when the stimulus is presented, but decays exponentially when the stimulus is absent. The results showed that, overall, the pigeons discriminated the relative frequencies well. Their accuracy always increased with the absolute value of the difference D and, for D > 0, it decreased with T. Performance also showed clear recency, primacy, and contextual effects. The model accounted well for the major trends in the data.     

Quantifiers and Congruence Closure

We prove some results about the limitations of the expressive power of quantifiers on finite structures. We define the concept of a bounded quantifier and prove that every relativizing quantifier which is bounded is already first-order definable (Theorem 3.8). We weaken the concept of congruence closed (see [6]) to weakly congruence closed by restricting to congruence relations where all classes have the same size. Adapting the concept of a thin quantifier (Caicedo [1]) to the framework of finite structures, we define the concept of a meager quantifier. We show that no proper extension of first-order logic by means of meager quantifiers is weakly congruence closed (Theorem 4.9). We prove the failure of the full congruence closure property for logics which extend first-order logic by means of meager quantifiers, arbitrary monadic quantifiers, and the Härtig quantifier (Theorem 6.1).     

Personality Profiles and Political Parties

This paper explores relationships between basic personality profiles of voters and their political party preferences. The Italian political system has moved recently from previously extreme, ideologically distinctive parties to form complex coalitions varying around more centrist orientations. Significant evidence was found for the utility of the Five-Factor Model of Personality in distinguishing between voters' expressed preferences, even given this greater subtlety in proposed values and agendas. More than 2,000 Italian voters who self-identified as having voted for new center-left or center-right political coalitions differed systematically in predicted directions on several personality dimensions measured by the Big Five Questionnaire. In the context of the model, center-right voters displayed more Energy and slightly more Conscientiousness than center-left voters, whose dominant personality characteristics were Agreeableness (Friendliness) and Openness; Emotional Stability was unrelated to either group. This relationship between individual differences in personality and political preferences was not influenced by the demographic variables of voters' gender, age, or education. Thus, personality dimensions proved to be stronger predictors of political preference than any of these standard predictor variables. Implications are discussed regarding links among personality, persuasion, power, and politics.     

Anxiety and counter-conditioning: the role of the behavioral inhibition system in the ability to associate aversive stimuli with future rewards

A total of 130 female undergraduates performed a counter-conditioning choice-task. This task presented two response alternatives and subjects were instructed to earn the maximum number of points. Responses to button 1 were normally followed by an immediate reward (an average gain of 7.5 points). Responses to button 2 were always followed by a punishment (an average loss of 20 points), but caused the next-but-one press on button 1 to give an average gain of 115 points. Thus, subjects were required to learn and maintain this counter-conditioning association. Four groups of subjects were formed according to the scores on the Sensitivity to Punishment and Sensitivity to Reward scales (which are measures of individual differences of Gray's anxiety and impulsivity personality dimensions, respectively). A 69.2% of subjects learned and maintained the counter-conditioning association. As predicted, personality results confirmed that subjects with lower scores on the Sensitivity to Punishment scale learned the counter-conditioning association better and faster when compared with high scorers. Results are consistent with Gray's Behavioral Inhibition System (BIS) model of anxiety which holds that individual differences in anxiety may relate to the ability to associate aversive stimuli with a future reward. Assuming that anxiety depends on BIS functioning, our results show that high trait anxious subjects, if compared with low anxious ones, would have a lower ability for associating an aversive event with a later appetitive one. This learning process would serve non-anxious subjects to reduce the aversiveness of cues of punishment and to cope better with stressful situations.     

Principles for Designing Randomized Preventive Trials in Mental Health: An Emerging Developmental Epidemiology Paradigm

An emerging population-based paradigm is now being used to guide the design of preventive trials used to test developmental models. We discuss elements of the designs of several ongoing randomized preventive trials involving reduction of risk for children of divorce, for children who exhibit behavioral or learning problems, and for children whose parents are being treated for depression. To test developmental models using this paradigm, we introduce three classes of design issues: design for prerandomization, design for intervention, and design for postintervention. For each of these areas, we present quantitative results from power calculations. Both scientific and cost implications of these power calculations are discussed in terms of variation among subjects on preintervention measures, unit of intervention, assignment, balancing, number of pretest and posttest measures, and the examination of moderation effects.     

Estimating multiple classification latent class models

This paper presents a new class of models for persons-by-items data. The essential new feature of this class is the representation of the persons: every person is represented by its membership tomultiple latent classes, each of which belongs to onelatent classification. The models can be considered as a formalization of the hypothesis that the responses come about in a process that involves the application of a number ofmental operations. Two algorithms for maximum likelihood (ML) and maximum a posteriori (MAP) estimation are described. They both make use of the tractability of the complete data likelihood to maximize the observed data likelihood. Properties of the MAP estimators (i.e., uniqueness and goodness-of-recovery) and the existence of asymptotic standard errors were examined in a simulation study. Then, one of these models is applied to the responses to a set of fraction addition problems. Finally, the models are compared to some related models in the literature.Thanks are to Paul De Boeck for creating the intellectually stimulating atmosphere in which this class of models came about, Iven van Mechelen for theone-sided idea, Kikumi Tatsuoka for the use of her data, and Theodoor Bouw for running part of the simulation study.