Whither geometry? Troubles of the geometric module

In rectangular arenas, rats often confuse diagonally opposite corners, even when distinctive cues differentiate them. This led to the postulation that rats rely preferentially on the geometry of space, encoded in a dedicated geometric module. Recent research casts doubt on this idea. Distinctive featural cues such as entire walls of a distinct color can hinder or aid the learning of geometry. In one situation in which using geometry would help greatly, rats had trouble learning the task. An associative model has been developed to capture these different learning processes, and view-based matching has been proposed as an alternative to the explicit coding of geometric cues. Considerations about how cues interact in learning are crucial in a recent theory of human spatial cognition.     

Creativity and dialectical phenomena From dialectical edge to dialectical space1

The seeds of creativity have the potential to germinate and flourish within the rich, ambiguous and unsettling tapestry of the core dialectical tensions related to the central organizing dialectic, life and death, generated in the patient‐analyst relating. The author introduces the concept of the ‘dialectical edge’ and describes it as the pivotal point in the dialectical struggle within these core dialectical dilemmas. This is a fluid, emotionally evocative threshold, where there is maximum potential for change, as well as for homeostatic stagnation. Drawing on Winnicott, the author illustrates how the presence of an edge within these dialectical dilemmas has the potential to open up into a creative, reflective space. He suggests that this, however, will depend on the therapist's capacity to contain/hold at this edge the arousing and intense affects‐such as anxiety, dread, excitement and passion‐that are inevitably generated at these pivotal relational moments. This will determine whether the patient will move forwards into the light of a creative, reflective, dialectical space, or backwards into collapsed, non‐reflective darkness, where fluid oscillation is transformed into rigid ossification. The author uses a clinical example to illustrate these dialectical phenomena, with a special focus on two clinically relevant dialectics, i.e. ‘ritual versus spontaneity’ and ‘closeness versus separateness’.     

Cognitive Tutor: Applied research in mathematics education

For 25 years, we have been working to build cognitive models of mathematics, which have become a basis for middle- and high-school curricula. We discuss the theoretical background of this approach and evidence that the resulting curricula are more effective than other approaches to instruction. We also discuss how embedding a well specified theory in our instructional software allows us to dynamically evaluate the effectiveness of our instruction at a more detailed level than was previously possible. The current widespread use of the software is allowing us to test hypotheses across large numbers of students. We believe that this will lead to new approaches both to understanding mathematical cognition and to improving instruction.     

Kitchener's Principle Ethics: Implications for Counseling Practice and Research

This extensive literature review examining the influence of K. S. Kitchener's (1984) introduction of principle ethics on counseling and psychology ethics notes the ultimate practicality of principle ethics. The authors maintain that although a strong influence of principle ethics in the area of counselor education emerges through the review, there is little clear evidence of influence in the areas of counseling research or practice. A primary reliance in the counseling professional literature on K. S. Kitchener's original work has likely resulted in a static understanding of the concepts and a concomitant theory–to–application knowledge gap. Implications include a more thorough and ongoing bridging between counseling ethics, philosophical ethics and practice, and a more overt presence of principle ethics.     

Sample size planning for the coefficient of variation from the accuracy in parameter estimation approach

The accuracy in parameter estimation approach to sample size planning is developed for the coefficient of variation, where the goal of the method is to obtain an accurate parameter estimate by achieving a sufficiently narrow confidence interval. The first method allows researchers to plan sample size so that the expected width of the confidence interval for the population coefficient of variation is sufficiently narrow. A modification allows a desired degree of assurance to be incorporated into the method, so that the obtained confidence interval will be sufficiently narrow with some specified probability (e.g., 85% assurance that the 95 confidence interval width will be no wider than to units). Tables of necessary sample size are provided for a variety of scenarios that may help researchers planning a study where the coefficient of variation is of interest plan an appropriate sample size in order to have a sufficiently narrow confidence interval, optionally with somespecified assurance of the confidence interval being sufficiently narrow. Freely available computer routines have been developed that allow researchers to easily implement all of the methods discussed in the article.     

Recovery from object substitution masking induced by transient suppression of visual motion processing: a repetitive transcranial magnetic stimulation study

Object substitution masking is a form of visual backward masking in which a briefly presented target is rendered invisible by a lingering mask that is too sparse to produce lower image-level interference. Recent studies suggested the importance of an updating process in a higher object-level representation, which should rely on the processing of visual motion, in this masking. Repetitive transcranial magnetic stimulation (rTMS) was used to investigate whether functional suppression of motion processing would selectively reduce substitution masking. rTMS-induced transient functional disruption of cortical area V5/MT+, which is important for motion analysis, or V1, which is reciprocally connected with V5/MT+, produced recovery from masking, whereas sham stimulation did not. Furthermore, masking remained undiminished following rTMS over the region 2 cm posterior to V5/MT+, ruling out nonspecific effects of real stimulation and confirming regional specificity of the rTMS effect. The results suggest that object continuity via the normal function of the visual motion processing system might in part contribute to this masking. The relation of these findings to the reentrant processing view of object substitution masking and other visual phenomena is discussed.