Learning a foreign language: Effects of tact and listener instruction on the emergence of bidirectional intraverbals

We evaluated the effects of tact and listener instruction on the emergence of bidirectional intraverbal relations with 6 typically developing Brazilian children, using an adapted alternating treatment design with pretest and posttest probes. In listener instruction, participants selected pictures that corresponded to spoken foreign-language words. For tact instruction, children had to vocalize foreign words in the presence of the corresponding pictures. After meeting mastery criteria, bidirectional intraverbal tests assessed vocalizations in Portuguese (native language) following the presentation of the equivalent words in English (foreign language) and vice versa. Tact instruction consistently produced higher levels of emergent intraverbal responding compared to listener instruction, confirming results from previous studies.     

Comparison of upright and flipped spoon presentations to guide treatment of food refusal

The current study examined the effects of bite placement with a flipped versus upright spoon on expulsion and mouth clean (product measure of swallowing) in the treatment of 3 children diagnosed with a pediatric feeding disorder and oral-motor deficits. For all 3 participants, extinction in the form of nonremoval of the spoon led to improvements in inappropriate mealtime behavior and acceptance of bites; however, re-presentation did not reduce expulsion or improve mouth clean. Results showed a lower level of expulsion and higher percentage of mouth clean during flipped spoon presentations and re-presentations for all participants. Findings from follow-up analyses supported transitioning back to an upright spoon in all 3 cases, although the time required for this to occur differed across participants.     

An Extension of Multiple Correspondence Analysis for Identifying Heterogeneous Subgroups of Respondents

An extension of multiple correspondence analysis is proposed that takes into account cluster-level heterogeneity in respondents’ preferences/choices. The method involves combining multiple correspondence analysis and k-means in a unified framework. The former is used for uncovering a low-dimensional space of multivariate categorical variables while the latter is used for identifying relatively homogeneous clusters of respondents. The proposed method offers an integrated graphical display that provides information on cluster-based structures inherent in multivariate categorical data as well as the interdependencies among the data. An empirical application is presented which demonstrates the usefulness of the proposed method and how it compares to several extant approaches. The work reported in this paper was supported by Grant 290439 and Grant A6394 from the Natural Sciences and Engineering Research Council of Canada to the first and third authors, respectively. We wish to thank Ulf B?ckenholt, Paul Green, and Marc Tomiuk for their insightful comments on an earlier version of this paper. We also wish to thank Byunghwa Yang for generously providing us with his data.     

Effects of Interspersed Brief Problems on Students' Endurance at Completing Math Work

An alternating treatments design was used to compare the effects of baseline, interspersed brief problems, and interspersed brief problems plus token reinforcement on students' endurance while completing math worksheets. By pairing the completion of brief problems with token reinforcement, the role of problem completion as a conditioned reinforcer was examined consistent with the discrete task completion hypothesis. Four 5th grade students who were low achieving in math participated. Each day the students completed a stack of math worksheets containing 3-digit by 3-digit addition problems with or without interspersed single-digit problems for 10 min. Dependent measures included total digits correct per session and during each min of the 10 min work period (i.e., a measure of endurance). Results indicated that total digits correct per session was highest during the interspersal plus reinforcement condition followed by interspersal and then baseline for three of the four students. In addition, both interspersal conditions resulted in greater endurance than baseline. Limitations of the current study and implications for increasing students' persistence on classroom tasks are discussed.     

Homogeneity analysis withk sets of variables: An alternating least squares method with optimal scaling features

Homogeneity analysis, or multiple correspondence analysis, is usually applied tok separate variables. In this paper we apply it to sets of variables by using sums within sets. The resulting technique is called OVERALS. It uses the notion of optimal scaling, with transformations that can be multiple or single. The single transformations consist of three types: nominal, ordinal, and numerical. The corresponding OVERALS computer program minimizes a least squares loss function by using an alternating least squares algorithm. Many existing linear and nonlinear multivariate analysis techniques are shown to be special cases of OVERALS. An application to data from an epidemiological survey is presented.This research was partly supported by SWOV (Institute for Road Safety Research) in Leidschendam, The Netherlands.     

Majorization as a tool for optimizing a class of matrix functions

The problem of minimizing a general matrix, trace function, possibly subject to certain constraints, is approached by means of majorizing this function by one having a simple quadratic shape and whose minimum is easily found. It is shown that the parameter set that minimizes the majorizing function also decreases the matrix trace function, which in turn provides a monotonically convergent algorithm for minimizing the matrix trace function iteratively. Three algorithms based on majorization for solving certain least squares problems are shown to be special cases. In addition, by means of several examples, it is noted how algorithms may be provided for a wide class of statistical optimization tasks for which no satisfactory algorithms seem available.The Netherlands organization for scientific research(NWO) is gratefully acknowledged for funding this project. This research was conducted while the author was supported by a PSYCHON-grant (560-267-011) from this organization. The author is obliged to Jos ten Berge, Willem Heiser, and Wim Krijnen for helpful comments on an earlier version of this paper.     

TREATING SELF-INJURY: WATER MIST SPRAY VERSUS FACIAL SCREENING OR FORCED ARM EXERCISE

In three experiments, the effect of water mist spray on self-injurious and collateral behaviors was compared with either facial screening or forced arm exercise. Water mist spray was as effective as facial screening in suppressing face-slapping in Experiment 1. However, it was not as effective as facial screening for self-injurious finger-licking in Experiment 2 or forced arm exercise for excessive ear-rubbing in Experiment 3. These results suggest that while water mist spray is effective, it may be less so than alternative procedures. In Experiments 2 and 3 there was a consistent decrease in the occurrence of untreated maladaptive behaviors. In addition, there was a moderate increase in appropriate social interaction in Experiment 2 and a substantial increase in Experiment 3.     

An efficient alternating least-squares algorithm to perform multidimensional unfolding

We consider the problem of least-squares fitting of squared distances in unfolding. An alternating procedure is proposed which fixes the row or column configuration in turn and finds the global optimum of the objective criterion with respect to the free parameters, iterating in this fashion until convergence is reached. A considerable simplification in the algorithm results, namely that this conditional global optimum is identified by performing a single unidimensional search for each point, irrespective of the dimensionality of the unfolding solution.This work originally formed part of a doctoral thesis (Greenacre, 1978) presented at the University of Paris VI. The authors acknowledge the helpful comments of John Gower during the first author's sabbatical at Rothamsted Experimental Station. The authors are also indebted to Alexander Shapiro, who came up with the proof of the key result which the authors had long suspected, but had not proved, namely that the smallest root of function (13) provides the global minimum of function (7). The constructive comments of the referees of this paper are acknowledged with thanks. This research was supported in part by the South African Council for Scientific and Industrial Research.     

AN ALTERNATING TREATMENTS COMPARISON OF TWO INTENSIVE INTERVENTIONS FOR FOOD REFUSAL

We compared two treatment packages involving negative reinforcement contingencies for 3 children with chronic food refusal. One involved physically guiding the child to accept food contingent on noncompliance, whereas the other involved nonremoval of the spoon until the child accepted the presented food. Subsequent to baseline, an alternating treatments comparison was implemented in a multiple baseline design across subjects. After each child had been exposed to at least nine sessions of each treatment condition and percentage of bites accepted had increased to at least 80%, the child's caregivers selected the preferred treatment package. The results indicated that both treatments were effective in establishing food acceptance. However, physical guidance was associated with fewer corollary behaviors, shorter meal durations, and parental preference.