Memory capacity, selective control, and value-directed remembering in children with and without attention-deficit/hyperactivity disorder (ADHD).

Objective: The ability to select what is important to remember, to attend to this information, and to recall high-value items leads to the efficient use of memory. The present study examined how children with and without attention-deficit/hyperactivity disorder (ADHD) performed on an incentive-based selectivity task in which to-be-remembered items were worth different point values. Method: Participants were 6–9 year old children with ADHD (n = 57) and without ADHD (n = 59). Using a selectivity task, participants studied words paired with point values and were asked to maximize their score, which was the overall value of the items they recalled. This task allows for measures of memory capacity and the ability to selectively remember high-value items. Results: Although there were no significant between-groups differences in the number of words recalled (memory capacity), children with ADHD were less selective than children in the control group in terms of the value of the items they recalled (control of memory). All children recalled more high-value items than low-value items and showed some learning with task experience, but children with ADHD Combined type did not efficiently maximize memory performance (as measured by a selectivity index) relative to children with ADHD Inattentive type and healthy controls, who did not differ significantly from one another. Conclusions: Children with ADHD Combined type exhibit impairments in the strategic and efficient encoding and recall of high-value items. The findings have implications for theories of memory dysfunction in childhood ADHD and the key role of metacognition, cognitive control, and value-directed remembering when considering the strategic use of memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Relation Between Television Exposure and Theory of Mind Among Preschoolers

This study explored the relation between preschoolers' television exposure and one important indicator of cognitive processing called theory of mind (ToM). A total of 107 preschoolers and their parents provided data on the preschoolers' television exposure (including both intentional viewing and exposure via background television), parent–child discussion of television, and preschoolers' ToM. The results indicated that preschoolers who were exposed to more background television and who had a television in their bedroom performed more poorly on ToM assessments compared with other children. Parent–child discussion of television was positively related to ToM performance, however. These results have implications for how we understand the effects of television on preschoolers.     

Metacognitive control over the distribution of practice: When is spacing preferred?

The authors clarify the source of a conflict between previous findings related to metacognitive control over the distribution of practice. In a study by L. Son (2004), learners were initially presented pairs of Graduate Record Examination (GRE) vocabulary words and their common synonyms for 1 s, after which they chose to study the pair again immediately (massed practice), later (spaced practice), or not at all (done). Learners chose spaced practice less as pair difficulty increased. A. S. Benjamin and R. D. Bird (2006), using different materials and procedures and a longer presentation duration (5 s), concluded just the opposite. The authors adopted Son’s materials and procedures and replicated her findings with a 1-s stimulus duration. However, the declining choice of spacing as item difficulty increased largely reflected learners’ failure to fully perceive items with brief presentations. With longer presentations, ensuring full perception, the choice of spaced practice increased with greater pair difficulty, in agreement with Benjamin and Bird. Theoretical implications are discussed in the context of discrepancy-reduction and proximal-learning perspectives. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Review and analysis of literature on self-management interventions to promote appropriate classroom behaviors (1988–2008).

In the late 1980s, J. W. Fantuzzo and colleagues conducted a review of the self-management literature in order to better define the characteristics of this class of interventions. Results indicated that many interventions were minimally student-directed despite the title “self-managed” and that student-managed interventions demonstrated incremental effects above teacher-managed interventions. In the current study, updated information was compiled with regard to how self-management interventions have been described, including the degree to which self-management interventions continue to rely on external (i.e., teacher) contingencies. Review of the literature identified 16 different characterizations of self-management interventions, each of which varied widely in terms of the number of intervention components included as well as the degree to which students were involved in implementation. Although self-observation and recording of a predefined behavior appear to be the cornerstones of self-management interventions, meaningful differences were noted, including whether reinforcement was involved and whether changes in performance were tracked over time. Furthermore, although self-management interventions appear to have undergone a small shift toward increased reliance on internal (i.e., student-managed) contingencies, adults continue to play a large role in the implementation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Next-generation tools for evolutionary invasion analyses

Evolutionary invasion analysis is a powerful technique for modelling in evolutionary biology. The general approach is to derive an expression for the growth rate of a mutant allele encoding some novel phenotype, and then to use this expression to predict long-term evolutionary outcomes. Mathematically, such ‘invasion fitness’ expressions are most often derived using standard linear stability analyses from dynamical systems theory. Interestingly, there is a mathematically equivalent approach to such stability analyses that is often employed in mathematical epidemiology, and that is based on so-called ‘next-generation’ matrices. Although this next-generation matrix approach has sometimes also been used in evolutionary invasion analyses, it is not yet common in this area despite the fact that it can sometimes greatly simplify calculations. The aim of this article is to bring the approach to a wider evolutionary audience in two ways. First, we review the next-generation matrix approach and provide a novel, and easily intuited, interpretation of how this approach relates to more standard techniques. Second, we illustrate next-generation methods in evolutionary invasion analysis through a series of informative examples. Although focusing primarily on evolutionary invasion analysis, we provide several insights that apply to biological modelling in general.     

A Study of Saccharomyces cerevisiae Cell Wall Glucans

Much research has been carried out over the years examining cell wall glucans from Saccharomyces cerevisiae and this study further examines aspects of the binding of (1r?4)‐α‐D‐glucan in the yeast cell wall, using a number of isolation techniques as well as monoclonal antibodies able to recognize a mixed (1r?4)‐α‐D‐glucan/(1r?6)‐β‐D‐glucan. Extraction of purified glucan, from S. cerevisiae cell wall, with 0.1N HCl, at 80°C for 6 h, released into the solution (1r?4)‐α‐D‐glucan and (1r?6)‐β‐D‐glucan as the major polysaccharides, along with an insoluble pellet highly enriched in (1r?3)‐β‐D‐glucan. The released (1r?4)‐α‐D‐glucan was composed of a high molecular size >100 kDa fraction (7.2% w/w) and a medium 5–50 kDa polysaccharide (10.2% w/w), with the (1r?4)‐α‐D‐glucan covalently bound to the (1r?6)‐β‐D‐glucan. The average molar ratio of the α:β glucan was 47: 53 in this mixed polysaccharide. The structure of this polysaccharide was different from the structure of plant starch or animal glycogen as monoclonal antibodies specific to yeast (1r?4)‐α‐D‐glucan/(1r?6)‐β‐D‐glucan did not recognize the plant starch or animal glycogen standards.     

Reading in graduate school: A survey of doctoral students in clinical psychology.

To what extent do graduate students in clinical psychology complete assigned readings? A total of 744 graduate students in American Psychological Association-accredited doctoral programs completed an online survey regarding reading in graduate school (67% response rate, of those viewing the survey). The reported amount of assigned reading varied widely, with an average of 330 pages per week. Compliance ratings suggested that about half the assigned reading is completed thoroughly and that thorough reading is more common than skimming or not reading assigned material. Motivating and hindering factors for reading are reported, and implications for faculty are considered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A fuzzy supplier selection model with the consideration of benefits,opportunities, costs and risks

Even though the research on supplier selection is abundant, the works usually only consider the critical success factors in the buyer–supplier relationship. However, the negative aspects of the buyer–supplier relationship must also be considered simultaneously. The main objective in this study is to propose an analytical approach to select suppliers under a fuzzy environment. A fuzzy analytic hierarchy process (FAHP) model, which incorporates the benefits, opportunities, costs and risks (BOCR) concept, is constructed to evaluate various aspects of suppliers. Multiple factors that are positively or negatively affecting the success of the relationship are analyzed by taking into account experts’ opinion on their importance, and a performance ranking of the suppliers is obtained. TFT-LCD manufacturers in Taiwan, which is the largest TFT-LCD producer country in the world, are facing increasing competition nowadays, and the selection of the most appropriate suppliers for cooperation is essential for firms to achieve competitive advantage. A case study of backlight unit supplier selection for a TFT-LCD manufacturer is presented, and the proposed model is applied to facilitate the decision process. The model is a general form that can be tailored and applied by firms that are making decisions on supplier selection.