Salt taste detection: an R-index approach to signal-detection measurements

The R-index approach to the signal-detection P(A) index of sensitivity was used to measure taste sensitivity to NaCl solutions. The R-index is the predicted probability of the correct choice of a signal, for a given signal-noise pair. For flow-wise and sipwise presentation, R-indices did not fluctuate significantly, provided subjects could not see the stimuli yet to be presented, indicating a lack of systematic sensitivity drift. The simultaneous measurement of more than one signal strength with reference to a common noise stimulus was seen to be a viable and sensitive procedure. Comparison of flow-wise and sipwise presentation of stimuli using R-indices, indicated that the former elicited greater subject sensitivity to NaCl taste.     

Divided attention, order of report and responses to immediately successive signals

Two effects, “divided-attention” and “order of report”, are operationally denned. Their relative contributions to the reduction in efficiency which accompanies the recognition of difficult nonverbal signals, presented simultaneously, is considered. Experiment I evaluated the two effects in the absence of a fixed order of report and emphasis instructions, confounding features of previous studies. The results showed: an overall impairment of performance with simultaneous signals; a contribution of both effects to the decrement, with a suggestion of the primacy of the “order of report” effect; and a significant interaction between the latter effect and modality, such that visual signals showed the greater effect. Experiment II using similar signals tested the assumption that simultaneity of presentation is a necessary condition for obtaining reduced efficiency with multiple signals. The assumption was only partially confirmed, a significant decrement in performance occurring only for the second of two successively presented signals. Similarities between the two sets of results are noted, as well as between these and modality differences obtained with verbal materials. Two possible accounts of the data are proposed, one based on “input”, the other on “storage” models of divided-attention. The hypothesis that subjects report the most clearly perceived signal first is rejected as an independent explanation.     

Mothers' resolution of their children's diagnosis: Organized patterns of caregiving representations

In this paper we examine mothers' representations of one form of trauma to the caregiving system: the experience of receiving a diagnosis of a chronic illness or disability in their child. An interview and classification system was used with 91 mothers of children ages 15–50 months with cerebral palsy or epilepsy. Mothers were classified as Resolved or Unresolved with respect to their child's diagnosis and grouped into subcategories within these major groups. Roughly half of these mothers were classified as Unresolved with respect to their child's diagnosis. Diagnosis type, severity of condition, developmental age, and time since receiving diagnosis were all unrelated to the distribution of Resolved/Unresolved classifications. Patterns of resolution in which cognitive strategies predominated were the most frequent form within the Resolved classification. Findings provide support for the organizational nature of caregiving representations as well as a number of implications for clinical practice.     

The mediation effect of student self-efficacy between teaching approaches and science achievement: findings from 2011 TIMSS US data

Over the past two decades, researchers consistently demonstrated the importance of science teaching approaches and student self-efficacy in influencing their science achievement. These findings have become the foundation of science education reform. However, empirical supports of these relationships are limited to direct relationships and small-scale studies. Therefore, little is known about the mechanism of how teaching approaches and student self-efficacy affect student achievement. In order to fill these gaps, this study used a multilevel structural equation modeling approach to analyze the direct and indirect relationships between teaching approaches, student self-efficacy, and science achievement by using the data of US eighth grade students in the 2011 TIMSS assessment. The results indicated that none of the teaching approaches identified in this study were directly associated with student science achievement, but significant mediation effect was found between generic teaching and student science achievement through student self-efficacy. Implications of these results for US educational system and reform were discussed.

     

Configural biases and reversible figures: evidence of multilevel grouping effects

Four experiments sought to identify the processes underlying 2 classes of grouping effects that are readily produced with a hierarchical figure type known as ambiguous triangles. Previous work has shown that aligning small equilateral triangles in particular configurations can both facilitate and interfere with observers' ability to report the pointing direction of the individual triangles. We determined that selectively adapting the observer to low-frequency gratings of the same orientation as the aligned triangles markedly altered the interfering and facilitative effects of the global configuration only when an accuracy measure of performance was used. When a response latency measure was used, no effect of the same adaptation condition was found. Results are discussed in terms of multiple levels of grouping effects in the visual system and the differential sensitivity of these levels to basic neural adaptation.