Instructed Hand Movements Affect Students’ Learning of an Abstract Concept From Video

Producing content-related gestures has been found to impact students’ learning, whether such gestures are spontaneously generated by the learner in the course of problem-solving, or participants are instructed to pose based on experimenter instructions during problem-solving and word learning. Few studies, however, have investigated the effect of (a) performing instructed gestures while learning concepts or (b) producing gestures without there being an implied connection between the gestures and the concepts being learned. The two studies reported here investigate the impact of instructed hand movements on students’ subsequent understanding of a concept. Students were asked to watch an instructional video—focused on the concept of statistical model—three times. Two experimental groups were given a secondary task to perform while watching the video, which involved moving their hands to mimic the placement and orientation of red rectangular bars overlaid on the video. Students were told that the focus of the study was multitasking, and that the instructed hand movements were unrelated to the material being learned. In the content-match group the placement of the hands reinforced the concept being explained, and in the content-mismatch group it did not. A control group was not asked to perform a secondary task. In both studies, findings indicate that students in the content-match group performed better on the posttest, and showed less variation in performance, than did students in the content-mismatch group, with control students falling in between. Instructed hand movement—even when presented as an unrelated, secondary task—can affect students’ learning of a complex concept.     

《伊斯兰教朝觐事务管理办法》解读

2020年8月27日,国家宗教事务局、外交部、公安部、文化和旅游部、国家卫生健康委员会、海关总署、国家市场监督管理总局、中国民用航空局令公布了《伊斯兰教朝觐事务管理办法》(以下简称《办法》),自2020年12月1日起实施。《办法》的公布实施,对于深入贯彻落实新修订《宗教事务条例》,规范伊斯兰教朝觐事务管理,保持朝觐活动正常秩序,维护民族团结和社会和谐,具有重要意义。     

Culture, temporal focus, and values of the past and the future

This article examines cultural differences in how people value future and past events. Throughout four studies, the authors found that European Canadians attached more monetary value to an event in the future than to an identical event in the past, whereas Chinese and Chinese Canadians placed more monetary value to a past event than to an identical future event. The authors also showed that temporal focus-thinking about the past or future-explained cultural influences on the temporal value asymmetry effect. Specifically, when induced to think about and focus on the future, Chinese valued the future more than the past, just like Euro-Canadians; when induced to think about and focus on the past, Euro-Canadians valued the past more than the future, just like Chinese.     

How to be proactive about interference: lessons from animal memory

Processes of proactive interference were explored using the pigeon as a model system of memory. This study shows that proactive interference extends back in time at least 16 trials (and as many minutes), revealing a continuum of interference and providing a framework for studying memory. Pigeons were tested in a delayed same/different task containing trial-unique pictures. On interference trials, sample pictures from previous trials reappeared as test pictures on different trials. Proactive-interference functions showed greatest interference from the most recent trial and with the longer of two delays (10 s vs. 1 s). These interference functions are accounted for by a time-estimation model based on signal detection theory. The model predicts that accuracy at test is determined solely by the ratio of the elapsed time since the offset of the current-trial sample to the elapsed time since the offset of the interfering sample. Implications for comparing memory of different species and different types of memory (e.g., familiarity vs. recollection) are discussed.     

Model Selection with the Linear Mixed Model for Longitudinal Data

Model building or model selection with linear mixed models (LMMs) is complicated by the presence of both fixed effects and random effects. The fixed effects structure and random effects structure are codependent, so selection of one influences the other. Most presentations of LMM in psychology and education are based on a multilevel or hierarchical approach in which the variance-covariance matrix of the random effects is assumed to be positive definite with nonzero values for the variances. When the number of fixed effects and random effects is unknown, the predominant approach to model building is a step-up method in which one starts with a limited model (e.g., few fixed and random intercepts) and then additional fixed effects and random effects are added based on statistical tests. A model building approach that has received less attention in psychology and education is a top-down method. In the top-down method, the initial model has a single random intercept but is loaded with fixed effects (also known as an “overelaborate” model). Based on the overelaborate fixed effects model, the need for additional random effects is determined. There has been little if any examination of the ability of these methods to identify a true population model (i.e., identifying the model that generated the data). The purpose of this article is to examine the performance of the step-up and top-down model building approaches for exploratory longitudinal data analysis. Student achievement data sets from the Chicago longitudinal study serve as the populations in the simulations.     

Kinetic study of static recrystallization in an Fe–Al–O ultra-fine-grained nanocomposite

A nearly abrupt coarsening of grains is observed in a newly developed Fe–Al–O ultra-fine-grained nanocomposite with a significant volume fraction (4%) of alumina nano-precipitates. The microstructure of the alloy was analysed in different states (as-received and annealed) by means of scanning electron microscopy, transmission electron microscopy (TEM) and hardness. The initial grain size 150–200 nm increases up to 50 μm during annealing 1000 °C/8 h and thereafter demonstrates saturation. A linear correlation between volume fraction of coarse grains and hardness was found. It was identified by TEM that alumina nano-precipitates stabilize the dislocation microstructure against recovery very effectively and the grain coarsening is due to fast growth of very few dislocation free grains. Thus, the observed grain coarsening has the attributes of static recrystallization.     

Visual properties and memorising scenes: Effects of image-space sparseness and uniformity

Previous studies have demonstrated that humans have a remarkable capacity to memorise a large number of scenes. The research on memorability has shown that memory performance can be predicted by the content of an image. We explored how remembering an image is affected by the image properties within the context of the reference set, including the extent to which it is different from its neighbours (image-space sparseness) and if it belongs to the same category as its neighbours (uniformity). We used a reference set of 2,048 scenes (64 categories), evaluated pairwise scene similarity using deep features from a pretrained convolutional neural network (CNN), and calculated the image-space sparseness and uniformity for each image. We ran three memory experiments, varying the memory workload with experiment length and colour/greyscale presentation. We measured the sensitivity and criterion value changes as a function of image-space sparseness and uniformity. Across all three experiments, we found separate effects of 1) sparseness on memory sensitivity, and 2) uniformity on the recognition criterion. People better remembered (and correctly rejected) images that were more separated from others. People tended to make more false alarms and fewer miss errors in images from categorically uniform portions of the image-space. We propose that both image-space properties affect human decisions when recognising images. Additionally, we found that colour presentation did not yield better memory performance over grayscale images.     

Executive turnover: the influence of dispersion and other pay system characteristics

Using tournament theory as a guiding theoretical framework, in this study, we assess the organizational implications of pay dispersion and other pay system characteristics on the likelihood of turnover among individual executives in organizational teams. Specifically, we estimate the effect of these pay system characteristics on executive turnover decisions. We use a multi-industry, multilevel data set composed of executives in publicly held firms to assess the effects of pay dispersion at the individual level. Consistent with previous findings, we find that pay dispersion is associated with an increased likelihood of executive turnover. In addition, we find that other pay characteristics also affect turnover, both directly and through a moderating effect on pay dispersion. Turnover is more likely when executives receive lower portions of overall top management team compensation and when they have more pay at risk. These conditions also moderate the relationship between pay dispersion and individual turnover decisions, as does receiving lower compensation relative to the market.