A new quantile estimator with weights based on a subsampling approach

Quantiles are widely used in both theoretical and applied statistics, and it is important to be able to deploy appropriate quantile estimators. To improve performance in the lower and upper quantiles, especially with small sample sizes, a new quantile estimator is introduced which is a weighted average of all order statistics. The new estimator, denoted NO, has desirable asymptotic properties. Moreover, it offers practical advantages over four estimators in terms of efficiency in most experimental settings. The Harrell–Davis quantile estimator, the default quantile estimator of the R programming language, the Sfakianakis–Verginis SV2 quantile estimator and a kernel quantile estimator. The NO quantile estimator is also utilized in comparing two independent groups with a percentile bootstrap method and, as expected, it is more successful than other estimators in controlling Type I error rates.     

Understanding allies’ participation in social change: A multiple perspectives approach

The introduction to the EJSP special issue brings together recent literature on allyship. We present and discuss different definitions of allyship and highlight a multiple perspectives approach to understanding the predictors and consequences of allyship. This approach suggests that engagement in allyship can be driven by egalitarian and non-egalitarian motivations and that the behaviours identified as allyship can have different meanings, causes and consequences depending on whether researchers take into account the allies’ perspective or the disadvantaged groups’ perspective. We use this approach as an organizing principle to identify themes that emerge in the papers included in this special issue. We start with four papers that consider the perspective of the advantaged group, followed by two papers that consider the perspective of the disadvantaged group. Finally, we introduce two theoretical papers that examine the relations between disadvantaged groups and allies, and we set out directions for future research.     

高创造力个体的群体差异性研究

高创造力群体的界定是创造力研究的重要前提,但迄今极少有研究关注以往研究中高创造力群体间的同质性问题。本研究以创造力问题提出能力测验调查了两所高校（一所地方高校和一所教育部直属高校）的975名大学生的创造力,通过极端组方法（extreme groups approach, EGA）为大学生创造力水平分组,考察不同创造力分组之间的差别。研究发现：地方高校和部属高校的高创造力大学生被试,在创造力的流畅性、变通性和独特性三个维度上,均存在显著差异。本研究结果提示,大学生高创造力组间可能存在质的差别,因此相关研究在外推结果时需要采取谨慎态度;研究者在实验过程中和讨论文献结果的可比性时一定要关注样本的同质性问题。     

Effects of cohabitation with another female on aggressive behaviour in pregnant mice

Pregnant, nonpregnant (but mated) and virgin females were individually housed or lived with a pregnant or nonpregnant cagemate. They were subjected to a series of successive daily encounters with a male intruder, the cagemate being excluded. The most aggressive subjects were pregnant females living with a pregnant cagemate. Isolated pregnant females were as aggressive as pregnant females with a nonpregnant cagemate. Nonpregnant and virgin females were the least aggressive. Nevertheless nonpregnant subjects living with a pregnant cagemate generated higher aggressive scores than nonpregnant females living alone. The way in which a pregnant cagemate influences the aggressive behaviour of another pregnant or nonpregnant female is discussed.     

Effects of minority status in the classroom on children's intergroup attitudes

Three studies examined the effects of relative group size on the development of children's intergroup attitudes. The studies employed a novel group paradigm in which elementary school children attending a summer school program were assigned to larger (i.e., majority) or smaller (i.e., minority) novel groups in their classroom (denoted by colored tee-shirts). In each study, relative group size was situated within a different classroom context. Study 1 examined the effects of relative group size when teachers made functional use of the novel groups and were themselves members of the novel groups. Study 2 examined the effects of relative group size in the absence of functional use. Study 3 examined the effects of relative group size when the classroom environment contained implicit messages about group status. In each study, children's intergroup attitudes (e.g., trait ratings, group evaluations) were assessed following several weeks in the classroom. The effect of relative group size on in-group bias was complex, varying as a function of (a) the relative size and salience of groups, (b) the measure used to assess intergroup attitudes, (c) group status (higher or lower), and (d) children's age.     

Factors contributing to the survival of self-help groups

Despite the growing utilization of self-help groups, there have been only a handful of studies that have examined the factors that contribute to their survival. The purpose of this study was to explore the factors that contribute to self-help group survival by examining their relationship with external sources (i.e., national and local self-help organizations, professionals) and group organizational characteristics (i.e., leadership diversification, recruitment, attendance at group meetings). Representatives from 245 active and 94 recently disbanded self-help groups were included in the analysis. Results indicated that the primary factors that discriminated between active and disbanded groups were the number of new people to attend a meeting, average group meeting attendance, length of existence, leadership diversification, outreach to potential group members, and support from national and local organizations. Results are discussed in terms of what national self-help organizations, self-help clearinghouses, and others who interact with self-help groups can do to empower and support them.     

Online group interaction and mental health: an analysis of three online discussion forums

The present study examined interactions on three Norwegian online discussion forums, and attempted to identify differences in interactions and plausible outcomes of thematically dissimilar forums. Four categories were applied to the forums in order to distinguish potentially constructive and destructive uses. Interaction along the constructive-destructive dimension was contingent upon the themes discussed, as well as the level and nature of professional involvement. Interaction adhering to a destructive dimension was identified only in relation to the forum for eating disorders. Discovering to what extent theme and professional involvement influence interactions in discussion forums might guide further professional involvement in online group settings and the design of appropriate online environments.     

Comprehension of reversible relative clauses in specifically language impaired and normally developing Greek children

This paper aims to investigate the syntactic comprehension of reversible relative clauses in a group of eight Greek children with specific language impairment (SLI) and two control groups of normally developing children matched on chronological and language age, respectively. An experiment using an acting out procedure was undertaken. Group analysis revealed that SLI children's performance is qualitatively different than that of both control groups. Interpreting the data, processes involved in syntactic comprehension are taken into consideration. It is claimed that processing demands impede SLI children's performance due to a deficit in their competence grammar.     

A controlled evaluation of group cognitive therapy in the treatment of irritable bowel syndrome

We randomized, at two sites, 210 patients with Rome II diagnosed irritable bowel syndrome (IBS), of at least moderate severity, to one of three conditions: group-based cognitive therapy (CT; n=120), psychoeducational support groups (n=46) as an active control, or intensive symptom and daily stress monitoring (n=44). One hundred eighty-eight participants completed the initial treatment. Those in symptom monitoring were then crossed over to CT. For an intent to treat analysis on a composite GI symptom measure derived from daily symptom diaries, both CT and the psychoeducational support groups were significantly more improved than those in the intensive symptom monitoring condition, but the CT and psychoeducational support group did not differ. Among treatment completers on the same composite measure of GI symptoms, again, both CT and psychoeducational support groups were statistically superior to symptom monitoring but did not differ on the symptom composite, or on any other measure. On individual IBS symptoms, both CT and psychoeducational support were statistically superior to symptom monitoring on reductions in abdominal pain and tenderness and for flatulence. Patient global ratings at the end of treatment showed the two active conditions statistically superior to symptom monitoring on change in Bowel Regularity, with CT superior to symptom monitoring on reduction in overall pain and in improvement in sense of well-being. Three-month follow-up data on 175 patients revealed maintenance of significant improvement or continued significant improvement on all IBS symptoms, including the McGill Pain Questionnaire. Group CT and psychoeducational support groups continued not to differ on any measure. We thus conclude that group CT is not superior to an attention placebo control condition.     

Learning from experience in case conference: A Bionian approach to teaching and consulting

In case conferences as well as didactic seminars, the power of the group can bring psychoanalytic education to life. However, primitive anxieties activated by group dynamics may also interfere with teaching and learning. The authors offer the example of a stalemated private practice case conference that had unconsciously organized against learning as the members began to read Bion's work. The case conference leader, an analyst, presented her case conference, which was mired in basic assumption dependency dynamics, to our peer consultation group. Drawing upon Bion's early contributions on groups, as well as his later ideas about thinking and mental growth, the peer group facilitated the case conference's return to work-group functioning and learning from experience. Activated in the peer group, commensal container↔contained processes gradually spread throughout the entire relational system of peer group, case-conference leader, case-conference members, and patients. This example underscores the importance of promoting within our institutes a culture in which faculty view themselves as part of an evolving intersubjective matrix that works to foster the containing capacities of candidates, patients, and faculty alike.