Stimulus class membership established via stimulus-reinforcer relations

In an arbitrary matching-to-sample procedure, two mentally retarded subjects learned conditional discriminations with two sets of stimuli. Each set included a spoken name (N1 or N2), an object (O1 or O2), and a printed symbol (S1 or S2). One subject selected conditionally (a) O1 upon N1, and O2 upon N2, and (b) S1 upon O1, and S2 upon O2. The other subject selected conditionally (a) S1 upon N1, and S2 upon N2, and (b) O1 upon S1, and O2 upon S2. For both subjects, selections of O1 and S1 produced one type of food, F1; selections of O2 and S2 produced a different type of food, F2. Both subjects also learned identity-matching performances, selecting O1, O2, S1, S2, F1, and F2 conditionally upon those stimuli as samples; F1 followed selections of O1, S1, and F1; F2 followed selections of O2, S2, and F2. Matching performances consistent with stimulus class formation involving the names, objects, symbols, and foods were demonstrated on probe trials, even though these performances had not been taught explicitly. Next, new objects, X1 and X2, were presented on identity-matching trials, producing F1 and F2, respectively. Without further training, X1 was selected conditionally upon N1, S1, and O1, and X2 was selected upon N2, S2, and O2. When the contingencies were changed so that selections of X1 and X2 were now followed by F2 and F1, respectively, X2 was selected conditionally upon N1, S1, and O1, and X1 was selected upon N2, S2, and O2. Class membership of X1 and X2 had apparently changed. This study provides evidence that reinforcers may become members of stimulus classes, and that new stimuli may become class members through relations with reinforcers.     

On structural equation modeling with data that are not missing completely at random

A general latent variable model is given which includes the specification of a missing data mechanism. This framework allows for an elucidating discussion of existing general multivariate theory bearing on maximum likelihood estimation with missing data. Here, missing completely at random is not a prerequisite for unbiased estimation in large samples, as when using the traditional listwise or pairwise present data approaches. The theory is connected with old and new results in the area of selection and factorial invariance. It is pointed out that in many applications, maximum likelihood estimation with missing data may be carried out by existing structural equation modeling software, such as LISREL and LISCOMP. Several sets of artifical data are generated within the general model framework. The proposed estimator is compared to the two traditional ones and found superior.The research of the first author was supported by grant No. SES-8312583 from the National Science Foundation and by a Spencer Foundation grant. We wish to thank Chuen-Rong Chan for drawing the path diagram.     

Motivations for parenthood among young adult college students

Two hundred and sixty three young adult college students responded to openended questions assessing their specific intentions, motives, and plans for having children. The most commonly stated motives for childbearing reflected a strong interest in establishing an identity and social network. Financial, marital, and emotional stability were identified as important factors influencing the timing of parenthood. Several significant sex differences were found for both motives and the timing of parenthood. These findings are discussed in terms of changing social norms regarding parenthood and changing sex role expectations.Portions of this research were presented at the Eastern Regional Psychological Association Convention in New York, April 1986. This research was funded by a grant from Trenton State College, Committee for Faculty and Institutional Research and Sabbatical Leave.     

Individual differences and measures of aggression in laboratory studies

After inducing hostility toward a confederate by threatening subjects' self-esteem, subjects were then given the opportunity either to deliver shocks (Experiment 1) or to withhold rewards (Experiment 2) from their confederate. Physiological measures were taken prior to the hostility induction, shortly after the induction and, finally, after the opportunity to aggress. Measures of individual differences relating to aggressive behavior were also considered. While the experimental manipulation was the best predictor in the ‘withholding rewards’ condition, measures of dissipation-rumination tendencies and emotional vulnerability were the best predictors in the ‘shock administration’ condition. In both conditions, systolic blood pressure seemed to reflect differences in arousal as a function of the hostility induction procedure, while subjects in the withhold rewards procedure also showed a decrease in systolic pressure after having an opportunity to aggress toward the confederate. It was concluded that not only is the withholding of rewards a more ethically acceptable procedure than shock administration, but it is also more likely to reflect experimental rather than individual difference affects.     

Three-dimensional perspective drawing of two-dimensional functions with microcomputers

In this paper, we present a BASIC program for Apple II series computers that allows the user to obtain perspective drawings of two-dimensional functions of known analytical expression. Also, we outline a procedure for obtaining perspective representations of two-dimensional arrays of data using the same program. The program should run on any computer with graphics mode with only slight modifications in the graphics commands.     

PRIMARY ENCOPRESIS: EVALUATION AND TREATMENT

Cathartic and behavioral treatment procedures for eliminating diurnal and nocturnal primary encopresis were investigated using a multiple-baseline design across four children. The dependent and independent variables measured were appropriate bowel movements, soiling accidents, independent toiletings, and cathartic use. Over 177 reliability observations (home visits) were conducted. For two of the children, treatment with cathartics and child-time remedied their soiling accidents and increased their independent toiletings in 8 to 11 weeks. While the cathartics and child-time increased the rate of appropriate bowel movements, they did not eliminate the soiling accidents with the other two children. Independent toiletings for these two children were achieved after 32 to 39 weeks of treatment when punishment procedures (positive practice, time-out, and hourly toilet sits) were incorporated and the suppositories were faded systematically.