Distraction effects in tasks of varying difficulty: Methodological issues in measuring development of distractibility

Effects of distraction on 5- and 8-year-old children's performance on a short-term memory task were examined. Tasks at three difficulty levels were employed to determine whether a floor effect could account for the lack of an age difference reported in an earlier study. A floor effect does not appear to be a key factor; the absolute amount of performance decrement was roughly equal for the two ages here regardless of task difficulty, and performance was well above chance under all conditions. The children adapted somewhat to the presence of distraction as shown in greater performance impairment for the first trial under distraction than for remaining trials. Use of a proportional, rather than an absolute, decrement index was considered, and the relevance of the present data to this issue was discussed.     

Nonmetric individual differences multidimensional scaling: An alternating least squares method with optimal scaling features

A new procedure is discussed which fits either the weighted or simple Euclidian model to data that may (a) be defined at either the nominal, ordinal, interval or ratio levels of measurement; (b) have missing observations; (c) be symmetric or asymmetric; (d) be conditional or unconditional; (e) be replicated or unreplicated; and (f) be continuous or discrete. Various special cases of the procedure include the most commonly used individual differences multidimensional scaling models, the familiar nonmetric multidimensional scaling model, and several other previously undiscussed variants.The procedure optimizes the fit of the model directly to the data (not to scalar products determined from the data) by an alternating least squares procedure which is convergent, very quick, and relatively free from local minimum problems.The procedure is evaluated via both Monte Carlo and empirical data. It is found to be robust in the face of measurement error, capable of recovering the true underlying configuration in the Monte Carlo situation, and capable of obtaining structures equivalent to those obtained by other less general procedures in the empirical situation.This project was supported in part by Research Grant No. MH10006 and Research Grant No. MH26504, awarded by the National Institute of Mental Health, DHEW. We wish to thank Robert F. Baker, J. Douglas Carroll, Joseph Kruskal, and Amnon Rapoport for comments on an earlier draft of this paper. Portions of the research reported here were presented to the spring meeting of the Psychometric Society, 1975. ALSCAL, a program to perform the computations discussed in this paper, may be obtained from any of the authors.Jan de Leeuw is currently at Datatheorie, Central Rekeninstituut, Wassenaarseweg 80, Leiden, The Netherlands. Yoshio Takane can be reached at the Department of Psychology, University of Tokyo, Tokyo, Japan.     

Multivariate analysis with linearizable regressions

We study the class of multivariate distributions in which all bivariate regressions can be linearized by separate transformation of each of the variables. This class seems more realistic than the multivariate normal or the elliptical distributions, and at the same time its study allows us to combine the results from multivariate analysis with optimal scaling and classical multivariate analysis. In particular a two-stage procedure which first scales the variables optimally, and then fits a simultaneous equations model, is studied in detail and is shown to have some desirable properties.     

Visual working memory in young children

Five experiments investigated immediate memory for drawings of familiar objects in children of different ages. The aims were to demonstrate younger children’s greater dependence on visual working memory and to explore the nature of this memory system. Experiment 1 showed that visual similarity of drawings impaired recall in young (5-year-old) children but not in older (10-year-old) children. Experiment 2 showed that younger and older children were affected in contrasting ways when the temporal order of recall was manipulated. Experiment 3 explored a recency effect found in backward recall and investigated its sensitivity to the presentation modality of materials used to produce retroactive interference (RI). For younger children, recency was reduced by visual but not by auditory-verbal RI; for older children, recency was more sensitive to auditoryverbal RI. Experiment 4 confirmed the effect of visual RI on visual recency in young children and showed that the same RI had little effect on their recall of spoken words. These results confirm younger children’s dependence on visual working memory. A final experiment showed that the effects of visual similarity and visual RI are additive, suggesting that they reflect different modes of accessing stored visuospatial information. Implications of these findings for developmental issues and for the nature of visual working memory are discussed.     

Medical ethics in Poland

The work related to medical ethics written by Polish authors are reviewed and some topics concerning teaching and various other activities in this field are presented. The attention is centered on the opinions and attitudes concerning the essence of medical profession and the personal model of the physician, doctor-patient relationship (including duties of the doctor), medical research on humans, abortion and other problems. The role of medico-ethical tradition in Poland is described. Main trends in polish ethical thought in relation to medicine are taken into consideration. General aspects of medical ethics in present-day Poland are tentatively characterized.     

Ethical and methodological aspects of medical computer data bases and knowledge bases

Ethical problems are related to computer data bases, containing data on individuals and groups of persons, as well as to computer knowledge bases, containing general rules and elements of expert systems.In the present essay the following conclusions are made regarding computer data bases: privacy, security, and confidentiality of medical computer data bases should be ensured. This duty should rest with physicians in hospitals. The principle of informed consent should be applied to gathering information which is to be stored and processed by computers. Information stored in computer data bases should not be used for purposes for which the subjects (patients as well as personnel) have not given their consent. In order to decrease the possibility of misuses of medical data bases containing information on individuals, these registers should not be linked to other central data bases.     

Emotion as a key concept in temperament research

A review of the literature shows that there is a growing interest in temperament that has developed in parallel to studies of emotion. The author adopts a historical perspective on the relationship between temperament and emotion and shows the place of emotion in current research on temperament. From this point of view, emotion may be considered as a trait mostly identified as emotionality (six different conceptions of emotionality have been proposed), as a specific affective-motivational process, as a hedonic tone determined by specific limbic structures, and as a behavioral characteristic described in terms of intensity and temporal parameters. Some theories of temperament concentrate only on one of the roles of emotion mentioned above, whereas in other theories several roles of emotion are exposed.