THE MODIFICATION OF LEISURE BEHAVIOR IN A HALF-WAY HOUSE FOR RETARDED WOMEN1

A multi-element baseline design combined with a multiple-baseline design, was used to investigate the effect of availability of materials, prizes for participation, and instruction on the leisure behavior of 14 mentally retarded women in a half-way house. A leisure program was conducted on weekday evenings, during which residents could choose to participate in any of six activities offered: puzzles, card games, clay, painting, weaving, and rug making. It was found that instruction in weaving and rug making significantly increased the percentage of residents participating in these activities, and that following instruction, prizes were not necessary to maintain high levels of participation. In contrast, prizes were more effective than mere availability of materials in maintaining participation in the other activities.     

Punishment-specific effects of pentobarbital: dependency on the type of punisher.

Pigeons were trained to peck a key under a multiple random-interval 1-minute, random-interval 6-minute schedule of food presentation. Subsequently, over three phases, additions were made during the random-interval 1-minute component as follows: pecks during the component occasionally were punished by timeout presentation (Phase 1), timeouts were presented independently of responding during the component (Phase 2), pecks during the component occasionally were punished by electric-shock presentation (Phase 3). In Phases 1 and 3, response-dependent timeout and shock suppressed responding and established equivalent rates in both components of the multiple schedule. Intermediate doses of pentobarbital increased responding suppressed by electric-shock punishment but had little or no effect on responding suppressed by timeout punishment. Response-independent presentation of timeouts did not result in suppression of responding (thus showing that response-dependent timeout acted as a punisher), and pentobarbital did not reliably increase unpunished responding. Pentobarbital's selective "punishment-attenuating" properties depend on the nature of the punisher.     

Multiple and concurrent schedule performance: independence from concurrent and successive schedule contexts

Six pigeons were trained on multiple variable-interval schedules and performance was measured in the presence or absence of another variable-interval schedule (the common schedule) arranged concurrently with both components. Manipulations included varying the rate of reinforcement on the common schedule, leaving the common schedule unchanged while the components of the multiple schedule were varied, varying the multiple schedule components in the absence of the common schedule, and varying one component of the multiple schedule while the other component and the common schedule were unchanged. The normal rate-increasing and rate-decreasing effects of reinforcement rate increase were found, except that changing one multiple schedule component did not affect the response rate in the successively available common schedule component. Both concurrent and multiple schedule performance undermatched obtained reinforcement-rate ratios, but the degree of undermatching in multiple schedules was reliably greater. Allocation of responses between multiple schedule components was unaffected by the concurrent availability of reinforcement, and allocation of responses between concurrent schedules was unaffected by the successive availability of different reinforcement rates.     

A molecular analysis of multiple schedule interactions: negative contrast

The present experiments investigated the relationship between changes in the relative reinforced interresponse-time distributions and the occurrence of positive and negative contrast in multiple variable-interval—variable-interval and multiple variable-interval—extinction schedules of reinforcement. Experiment I demonstrated that changes in the interresponse-time distributions were consistently correlated with response-rate changes referred to as positive and negative contrast. Corresponding changes in the reinforced interresponse-time distributions suggested that negative contrast resulted as an inductive effect of selectively reinforcing long interresponse times in the altered component at the moment the baseline schedule was reintroduced. Experiment II demonstrated that the magnitude of the negative-contrast effect could be significantly decreased if the altered component schedule was modified in order to prevent the reinforcement of these interresponse times during the first few sessions of baseline recovery. The results supported a proposal that interresponse time—reinforcer relations may act as amplifiers or attenuators of negative contrast.     

A note on moran's measure of multiple rank correlation

A measure of multiple rank correlation,T _y.12 ², is proposed for the situation with no tied observations in the variables. The measure is a weighted average of two squared Kendall taus. It is shown thatT _y.12 ² is equivalent to a statistic previously proposed by Moran and thus a new interpretation is given to Moran's statistic.The author wishes to thank Nancy Anderson, Willard Larkin, and Kent Norman for their helpful comments.     

A dialogue on Zeno's paradox of Achilles and the tortoise

The five participants in this dialogue critically discuss Zeno of Elea's paradox of Achilles and the tortoise. They consider a number of solutions to and restatements of the paradox, together with their philosophical implications. Among the issues investigated include the appearance-reality distinction, Aristotle's distinction between actual and potential infinity, the concept of a continuum, Cantor's continuum hypothesis and theory of transfinite ordinals, and, as a solution to Zeno's puzzle, the distinction between infinite and indeterminate or inexhaustible divisibility.     

TEACHING PERSONS WITH PROFOUND MULTIPLE HANDICAPS: A REVIEW OF THE EFFECTS OF BEHAVIORAL RESEARCH

The behavioral research on teaching individuals who have profound multiple handicaps is reviewed. The primary focus is on determining the degree to which behavioral research has demonstrated the teaching of meaningful skills to this population. Results of the review indicate that investigations have demonstrated, albeit inconsistently, that behavior change has resulted from contingency management interventions with persons who have profound multiple handicaps. However, there is little evidence that such interventions have resulted in meaningful behavior change according to currently accepted criteria for beneficially affecting the quality of life of persons with serious handicaps. Potential explanations for the lack of such evidence are offered, including the relative lack of research attention given to this issue, the possible ineffectiveness of the components of the technology applied, and possible ineffective application of the potentially effective technology. Suggestions for future research are discussed in terms of developing more effective educational and habilitative services for persons with profound multiple handicaps. In particular, we suggest research on a wider variety of behavioral teaching procedures, providing more comprehensive evaluations of the applications of procedures and developing treatment programs that do not focus solely on traditional skill acquisition.     

EM and beyond

The basic theme of the EM algorithm, to repeatedly use complete-data methods to solve incomplete data problems, is also a theme of several more recent statistical techniques. These techniques—multiple imputation, data augmentation, stochastic relaxation, and sampling importance resampling—combine simulation techniques with complete-data methods to attack problems that are difficult or impossible for EM.A preliminary version of this article was the Keynote Address at the 1987 European Meeting of the Psychometric Society June 24–26, 1987 in Enschede, The Netherlands. The author wishes to thank the editor and reviewers for helpful comments.     

A resolution to the interpretive dilemmas created by the Minnesota Multiphasic Personality Inventory 2 (MMPI-2)? A reply to Ben-Porath and Graham

In my original article (Strassberg, 1991) I described (1)some of the changes introduced by the MMPI-2, (2) possible interpretive dilemmas created by these changes, and (3) strategies for dealing with these dilemmas. In their reply to my paper, Ben-Porath and Graham (preceding paper) suggest that the differences between the MMPI-2 and the MMPI (1) are to be expected, (2) are less important than I imply, and (3) when they do occur, will almost always reveal the superiority of the MMPI-2. In this reply to Ben-Porath and Graham, I explain why, despite their reassurances, I continue to contend that interpretive dilemmas can exist when using the MMPI-2, but these should not deter us from using this instrument.     

Interpretive dilemmas created by the minnesota multiphasic personality inventory 2 (MMPI-2)

While the new MMPI-2 has the potential to provide more and better clinically relevant information than its predecessor, its introduction also creates several important problems for clinicians and researchers. In particular, the new norms and the use of uniform (rather than linear) T-scores result in the same raw scores on the two tests yielding clinical profiles that can be quite different, both qualitatively and quantitatively. These differences can result in difficulty in MMPI-2 profile interpretation when the user is relying on MMPI interpretive strategies. This paper addresses these concerns and offers some temporary remedial strategies.