Reward contrast in delay and probability discounting

In this study, we examined whether reward contrast influences choice between delayed and probabilistic outcomes. Specifically, we predicted that the subjective value of an intermediate reward would seem relatively larger or smaller, respectively, if it followed choices involving a smaller or larger reward and would produce corresponding changes in rates of delay and probability discounting. In Experiment 1, subjects made choices about hypothetical 5,000 or5,000 or 50 outcomes and then made choices about 500 outcomes. Delay-discounting rates for the500 outcomes. Delay-discounting rates for the 500 outcome were larger for Group 5,000 than for Group5,000 than for Group 50, whereas the opposite result was obtained for probability-discounting rates. In Experiment 2, we used a design that allowed for contrast effects to be assessed within subjects. Two groups made choices about delayed or probabilistic rewards. After completing question blocks in which the amount was 5,000 or5,000 or 50, subjects responded to questions with an intermediate amount (475/475/525). For Group Delay, the present value of the intermediate reward was greater after the 50 block than after the50 block than after the 5,000 block, whereas the opposite was obtained for Group Probability. The results from both experiments confirmed the predictions of reward contrast and suggested that the subjective value of a monetary reward varies inversely with the prior reward amount.     

Capturing and Enhancing Science Teachers’ Professional Knowledge

This paper reports research from a three-year Australian science teacher professional learning project, the Science Teaching and Learning (STaL) Project, in which groups of science teacher participants (across years K – 12) worked with academics over a one-year period as teacher researchers. Through reflecting on their experiences within the STaL Project and collecting data from their classrooms related to specific science teaching concerns, teacher participants constructed cases around particular aspects of their professional learning. The cases that these participants developed elicited rich insights into their teaching and their students’ learning of science. This paper discusses how the cases were developed by the teacher researcher participants and uses exemplars as a way of illustrating the nature of the professional knowledge developed.     

Preparing for principalship from the crucible of experience: reflecting on theory,practice and research

This paper examines the theories of organisation that have informed our understanding of schools as complex social worlds and the practice of school leadership that seems to be required in such environments. This understanding has, in turn, determined the research approach we have adopted for investigating principals’ work and for ascertaining the utility of existing approaches to their initial preparation. The paper argues that the extent to which preparation processes align with principals’ professional needs will depend on the extent to which they are able to connect with the realities of workplaces found in schools as well as the environments in which they are located. For this purpose, it is desirable to pursue the kind of enquiry that is capable of revealing what schools leaders know and brings them to a new stage in their thinking about practice.     

An intensification approach to double-block algebra: A pilot implementation of Intensified Algebra in a large urban school district

Double-block instruction has become a popular strategy for supporting struggling mathematics students in algebra I. Despite its widespread adoption, little consistent evidence supports the attributes of a successful double-block design or the effectiveness of this instructional strategy. In this study, the authors examine a pilot implementation of a double-block strategy—instantiated in the program Intensified Algebra—that combines core algebra content with insights from research on how students learn mathematics and explicit noncognitive supports focused on key attitudes, beliefs, and behaviors essential to student success. The results of the study show that, when implemented with fidelity, participation in the program significantly increased student achievement on the state end-of-course algebra I assessment.     

Effect of verbal instructions and image size on visual search strategies in basketball free throw shooting

We assessed the effects on basketball free throw performance of two types of verbal directions with an external attentional focus. Novices ( n = 16) were pre-tested on free throw performance and assigned to two groups of similar ability ( n = 8 in each). Both groups received verbal instructions with an external focus on either movement dynamics (movement form) or movement effects (e.g. ball trajectory relative to basket). The participants also observed a skilled model performing the task on either a small or large screen monitor, to ascertain the effects of visual presentation mode on task performance. After observation of six videotaped trials, all participants were given a post-test. Visual search patterns were monitored during observation and cross-referenced with performance on the pre- and post-test. Group effects were noted for verbal instructions and image size on visual search strategies and free throw performance. The 'movement effects' group saw a significant improvement in outcome scores between the pre-test and post-test. These results supported evidence that this group spent more viewing time on information outside the body than the 'movement dynamics' group. Image size affected both groups equally with more fixations of shorter duration when viewing the small screen. The results support the benefits of instructions when observing a model with an external focus on movement effects, not dynamics.     

Choose your primary outcome variables with care

The changes in postural tremor of the hand and the subsequent effect on shooting performance produced by moderate cooling and heating of the forearm were studied in six subjects. Cooling produced a large decrease in tremor size of the ipsilateral hand, whereas warming the limb produced an increase in tremor size. Cooling or warming the forearm did not change the peak frequency of tremor significantly, which was quite stable for each subject. The improvement in shooting performance after cooling the forearm, as measured by grouping pattern of the shots, reached statistical significance and warming caused a significant worsening. This measure of performance was shown to correlate (r = 0.776) inversely with tremor size. The causes and implications of these changes are discussed. It is suggested that local cooling may be useful for people who wish temporarily to reduce tremor in order to improve dexterity for shooting and for other purposes.     

The reliability and validity of the bar-mounted PUSH BandTM 2.0 during bench press with moderate and heavy loads

ABSTRACT

The aim of this study was to assess the reliability and validity of the bar-mounted PUSH Band^TM 2.0 to determine peak and mean velocity during the bench press exercise with a moderate (60% one repetition maximum [1RM]) and heavy (90% 1RM) load. We did this by simultaneously recording peak and mean velocity using the PUSH Band^TM 2.0 and three-dimensional motion capture from participants bench pressing with 60% and 90% 1RM. We used ordinary least products regression to assess within-session reliability and whether the PUSH Band^TM 2.0 could accurately predict motion capture velocity. Results showed that PUSH Band^TM 2.0 and motion capture peak and mean velocity reliability was acceptable with both loads. While there was a tendency for the PUSH Band^TM 2.0 to slightly overestimate peak and mean velocity, there was no fixed bias. However, mean velocity with 60 and 90% 1RM demonstrated proportional bias (differences between predicted and motion capture values increase with magnitude). Therefore, PUSH Band^TM 2.0 peak velocity with 60 and 90% 1RM is valid, but mean velocity is not.