A program for parsing mouse movements into component submovements

Most current movement control theories include the idea that movement toward a target can be broken into several submovements. The complexity of analyzing a movement into its constituent submovement structure and the additional complexity imposed by the problem of noise in the data and hand tremor seem to be daunting to researchers. This paper discusses a program that can ameliorate both of these problems and parse movements into their constituent submovements. It also contains a graphing feature that is useful as a visual tool for analyzing submovement structure. The programs are easily modifiable, so that researchers can specify their own parsing rules on the basis of different assumptions about movement control and use the parser for data from different experimental tasks.     

Spline smoothing with model-based penalties

Nonparametric regression techniques, which estimate functions directly from noisy data rather than relying on specific parametric models, now play a central role in statistical analysis. We can improve the efficiency and other aspects of a nonparametric curve estimate by using prior knowledge about general features of the curve in the smoothing process. Spline smoothing is extended in this paper to express this prior knowledge in the form of a linear differential operator that annihilates a specified parametric model for the data. Roughness in the fitted function is defined in terms of the integrated square of this operator applied to the fitted function. A fastO(n) algorithm is outlined for this smart smoothing process. Illustrations are provided of where this technique proves useful.     

Opportunities For Learning: Course Sequences and Positional Advantages

Course sequences are strands of courses in particular content areas that span a student's educational career. Courses that are differentiated and sequentially organized, such as mathematics and science course sequences, create opportunities for positional advantages in a school's curricular structure. When students make a nonroutine change of schools – that is, transferring to a school outside of the regular attendance zone – they are at risk of changing their positional advantage. Using data from the National Education Longitudinal Study of 1988–94 (NELS:88–94), we examine the educational outcomes of sequences and explore curricular dislocations within the context of school choice. We find that the strongest predictors of 12th-grade mathematics and science course sequences are a student's course sequences at 10th grade. With regard to outcomes, students in higher mathematics and science sequences show greater achievement gains. Furthermore, students in higher mathematics sequences are less likely to have behavior problems and are more likely to graduate from high school and attend college. Students who make a nonroutine change of schools are more likely to be in lower course sequences than students who do not transfer. Thus, course sequences in mathematics and science are tangible experiences with real consequences for students' lives during and beyond high school and are sensitive to transitions which disrupt the continuity of students' high school careers.     

Need probability affects retention: A direct demonstration

Recent memory theory has emphasized the concept ofneed probability—that is, the probability that a given piece of learned information will be tested at some point in the future. It has been proposed that, in real-world situations, need probability declines over time and that the memory-loss rate is calibrated to match the progressive reduction in need probability (J. R. Anderson & Schooler, 1991). The present experiments were designed to examine the influence of the slope of the need-probability curve on the slope of the retention curve. On each of several trials, subjects memorized a list of digits, then retained the digits in memory for 1, 2, 4, 8, or 16 sec. Some trials ended with a recall test; other trials ended with the message, “no test.” In Experiment 1, the likelihood of encountering a memory test (i.e., the need probability) was made to either increase or decrease as the retention interval increased; in Experiment 2, need probability either was flat (invariant across retention intervals) or decreased as the retention interval increased. The results indicated that the shape of the need-probability curve influenced the slope of the retention curve (Experiment 1) and that the effect became larger as the experimental session progressed (Experiment 2). The findings support the notion that memory adapts to need probabilities and that the rate of forgetting is influenced by the slope of the need-probability curve. In addition, all of the forgetting curves approximated a power function, suggesting that need probability influences the slope but not the form of forgetting.     

The Journal of Abnormal Child Psychology at 25

This issue, redesigned in a new format, marks the beginning of Volume 25, the beginning of the silver anniversary year of the Journal of Abnormal Child Psychology. Data were compiled from the first 24 volumes to study changes over time, and Pearson correlations were calculated to determine linear trends in the journal's development The number of articles per volume has doubled, from about 25 to 50. In recent years the first authors of articles were more likely to be located outside the U.S. (up from about 5% to about 25%). Also, in recent years the first authors of articles were less likely to be affiliated with nonmedical school university departments and more likely to be affiliated with medical schools or research institutes. An introduction to this special 25th anniversary issue is provided.     

The U.S. Supreme Court Decision in Jaffee v. Redmond: Implications for Counselors

In 1996, the U.S. Supreme Court held that communications between licensed psychotherapists and their patients are privileged under the Federal Rules of Evidence. The nature of privileged communication, the history of this Supreme Court decision, and implications of the decision for counselors are discussed.     

THE EFFECTS OF ALIGNABILITY ON MEMORY

Abstract— According to structure-mapping theory, the process of comparison in one of alignment and mapping between representational structures. This process induces a focus on commonalities and alignable differences (i.e., those related to the commonalities). Non-alignable differences (i.e., those not related to the commonalities) are held to be neglected. The theory thus predicts increased focus on the corresponding information, Whether these are commonalities or differences. In this article, we explore the implications of this claim for memory: Specifically, we test the prediction that alignable differences are more likely to be processed and stored than nonalignable differences.
We present a study in which people made similarity comparisons between pairs of pictures and then were probed for recall. The recall probes were figures taken from the pictures and were either alignable or nonalignable differences between the pairs. The alignable differences were better memory probes than the nonalignable differences, suggesting that people were more likely to encode and store the corresponding information than the noncorresponding information.     

Dialektik Und Formalisierung

Dialectics and Formalization. In an appendix to his article Can the concept of dialectic be made clear? (JGPS 27: 131–165) the author critically examined an attempt by D. Wandschneider of reconstructing Hegelian dialectical logic by displaying antinomic structures. The main steps of this reconstruction were formalized within the framework of second order predicate logic. In his reply (JGPS 27: 347–352) Wandschneider argues that formalization is the wrong way of interpreting and judging his reconstruction project on the ground that the understanding of predication is already presupposed by predicate logic and, therefore, cannot be formalized. In the present contribution it is shown that Wandschneider's criticism is based on a fundamentally mistaken conception of formalization and formal logic and that the problems posed by his project remain completely unresolved.