Computational behavior dynamics: an alternative description of Nevin (1969).

A computational processing behavior-dynamic model was instantiated in the form of a computer program that "behaved" on the task developed by Nevin (1969). In this classic discrete-trials experiment, the relative frequency of choosing a response alternative matched the relative frequency of reinforcement for that alternative, the local structure of responding was opposite that predicted by momentary maximizing (i.e., the probability of a changeover decreased with run length), and absolute and relative response rates varied independently. The behavior-dynamic model developed here qualitatively reproduced these three results (but not in quantitative and specific detail) and also generated some interesting, as-yet-untested predictions about performance in Nevin's task. The model was discussed as an example of a stochastic behavior-dynamic alternative to algebraic behavior theory.     

Evaluating young children''s cognitive capacities through computer versus hand drawings

Young normal and handicapped children, aged 3 to 6 years, were taught to draw a scene of a house, garden and a sky with a computer drawing program that uses icons and is operated by a mouse. The drawings were rated by a team of experts on a 7-category scale. The children's computer- and hand-produced drawings were compared with one another and with results on cognitive, visual and fine motor tests. The computer drawing program made it possible for the children to accurately draw closed shapes, to get instant feedback on the adequacy of the drawing, and to make corrections with ease. It was hypothesized that these features would compensate for the young children's limitations in such cognitive skills, as memory, concentration, planning and accomplishment, as well as their weak motor skills. In addition, it was hypothesized that traditional cognitive ratings of hand drawings may underestimate young children's intellectual ability, because drawing by hand demands motor skills and memory, concentration and planning skills that are more developed than that actually shown by young children. To test the latter hypothesis, the children completed a training program in using a computer to make drawings. The results show that cognitive processes such as planning, analysis and synthesis can be investigated by means of a computer drawing program in a way not possible using traditional pencil and paper drawings. It can be said that the method used here made it possible to measure cognitive abilities "under the floor" of what is ordinarily possible by means of traditionally hand drawings.     

The accuracy of maternal self-reports: Agreement between reports on a computer simulation compared with observed behaviour in the supermarket

The validity of maternal self-reports about their parenting behaviour is evaluated with two studies. In both studies, the mothers were observed shopping in the supermarket with their 2-year-old children. One week later they responded to multiple choice questions on a computer that simulated the experience of shopping with their children. The exact agreement between the two types of data was then assessed. The results from the first study involving 28 mothers revealed some agreement, although it was generally low. In an effort to increase the level of agreement, the computer simulation was revised to allow multiple responses and to clarify some of the simulation vigenettes. A replication study resulted in a considerably higher level of agreement for 22 mothers. Implications of this method for researchers and practitioners are discussed.     

Multilevel models in developmental psychological research: Rationales and applications

The armoury of statistical techniques has recently been enhanced with the multilevel model for longitudinal data. The present article explains the multilevel model for longitudinal data to the statistically non-sophisticated reader. It shows how the model relates to the five rationales of longitudinal research, as they were put forward by Baltes and Nesselroade (1979). In addition, it shows how the model matches Wohlwill's methodology of developmental functions. To elucidate the model further, three applications are given. The applications pertain to the development of children's sleeping duration during the first 18 months of life, the effects of early hospitalization on the daily frequency of crying, and the developmental relationship between social and solitary play.     

Effects of modelling on children''s pretend play

The effects of modelling on pretend play were studied in children between 2.6 and 3.6 years of age by examining changes both in the action and language-based expressions of pretending. Three modelled scenes were demonstrated with the same realistic toys used by the child in the pre-modelling phase. The results gave support to the idea of the effectiveness of modelling. The effects of the modelled scenes were clearest among children whose pre-modelling play consisted of object-centred actions including few of pretending. The post-modelling play of this subgroup showed better quality of action and language categories and integration measures. Among the decentred players no significant action benefit could be achieved. This might have been an outcome of the contextual limits of the toy material and of the drop of play motivation caused by the model interruption. However, these children expressed verbal pretending revealing significant pre-post effects for inventive utterances.     

An infrared system for the detection of a pigeon''s pecks at alphanumeric characters on a TV screen: the dependency of letter detection on the predictability of one letter by another.

Three pigeons pecked at letters of the alphabet and at the symbol "?" displayed on a computer-driven cathode ray screen. A 4 by 4 matrix of infrared emitting and detecting diodes and associated circuitry identified the location of a pigeon''s responses to the screen. Responses at the target letter T were probabilistically reinforced with food whenever T appeared in a string of three letters in the middle of the screen. Responses at the symbol "?" appearing below this string were probabilistically reinforced whenever T did not appear. The letter F anywhere in the three-character string either strongly predicted the occurrence of the target letter T, in two conditions, or predicted its nonoccurrence, in a third. This manipulation of the frequency with which the familiar letter F predicted T was shown to change the function relating probability of a correct peck at the symbol "?" to the number of Fs in the string. This effect may be interpreted as an instance of the phenomenon where an organism''s acquired knowledge changes what it sees.     

Heterogeneous heterogeneity by default: Testing categorical moderators in mixed-effects meta-analysis

Categorical moderators are often included in mixed-effects meta-analysis to explain heterogeneity in effect sizes. An assumption in tests of categorical moderator effects is that of a constant between-study variance across all levels of the moderator. Although it rarely receives serious thought, there can be statistical ramifications to upholding this assumption. We propose that researchers should instead default to assuming unequal between-study variances when analysing categorical moderators. To achieve this, we suggest using a mixed-effects location-scale model (MELSM) to allow group-specific estimates for the between-study variance. In two extensive simulation studies, we show that in terms of Type I error and statistical power, little is lost by using the MELSM for moderator tests, but there can be serious costs when an equal variance mixed-effects model (MEM) is used. Most notably, in scenarios with balanced sample sizes or equal between-study variance, the Type I error and power rates are nearly identical between the MEM and the MELSM. On the other hand, with imbalanced sample sizes and unequal variances, the Type I error rate under the MEM can be grossly inflated or overly conservative, whereas the MELSM does comparatively well in controlling the Type I error across the majority of cases. A notable exception where the MELSM did not clearly outperform the MEM was in the case of few studies (e.g., 5). With respect to power, the MELSM had similar or higher power than the MEM in conditions where the latter produced non-inflated Type 1 error rates. Together, our results support the idea that assuming unequal between-study variances is preferred as a default strategy when testing categorical moderators.     

LEVEL OF INTERACTIVITY OF VIDEODISC INSTRUCTION ON COLLEGE STUDENTS' RECALL OF AIDS INFORMATION

Experiment 1 confirmed the greater effectiveness of constructed-response interactive videodisc instruction when compared to a click-to-continue or passive viewing formats on posttest recall of AIDS information by 101 college students. Experiment 2 extended the analysis using a counterbalanced (ABAB-BABA) intrasubject design with 4 students in each of three ability groups. The necessity of constructing answers appears to be an important factor in the effectiveness of instructional programs.     

Teaching simple addition to children with mental retardation using a microcomputer

Computer assisted instruction (CAI) was used for improving the efficiency of simple addition (single-digit without carrying) computation in three children with mental retardation. The training program, conducted on a portable personal computer, consisted of demonstrations and repetitive practices on simple addition presented in a vertical format. A number of behavioral instruction techniques such as direct feedback, corrective demonstration, verbal association, and token reinforcement were also included. To evaluate the effects of the CAI package, a multiple-baseline across subjects design with followup was employed. Results showed that performances of children improved with training and were maintained at 1-week, 4-week, and 12-week followups. Generalization of the learned skills was evident when children were assessed on a paper-and-pencil addition test in a vertical format. The skills were also transferable, with initial prompting, to a computerized addition test in a horizontal format. These findings reaffirmed the applicability of CAI and behavioral techniques for teaching math skills to children with mental retardation.     

Introduction and overview: Global information ethics

This is an introduction to a set of papers on Computer Ethics from the conference ETHICOMP95. Taken as a whole, the collection of papers provides arguments and concepts to launch a new development in computer ethics: ‘Global Information Ethics’. A rationale for globalization is provided, as well as some early efforts which move in that direction. ETHICOMP95, an international conference on Computer Ethics, was held 28–30 March 1995 at De Montfort University, Leicester, UK. Co-directors were Terrell Ward Bynum and Simon Rogerson.