A technique for converting from intravenous drug self-administration to liquid reinforcement

A rapid inexpensive technique for changing from intravenous drug self-administration (DSA) to liquid reinforcement is described. Utilizing a standard peristaltic-type infusion pump typically used in DSA experiments and a specially designed drinking cup, the changeover from intravenous DSA to liquid reinforcement can be accomplished in a few minutes at a cost of less than $10.     

Statistical significance tests for binormal ROC curves

Statistical significance tests are derived and evaluated for measuring apparent differences between an obtained and an expected binormal ROC curve, between two independent binormal ROC curves, and among groups of independent binormal ROC curves. A binormal ROC curve is described by two parameters which represent the spread of the means and the ratio of the standard deviations of the two underlying Gaussian decision variable distributions. To test the significance of apparent differences between or among ROC curves, approximate χ² statistics for each of the three tests were constructed from maximum likelihood estimates of the two parameters defining the binormal ROC curve. The performance of each test statistic was evaluated by simulating five-category rating scale data with equal numbers of noise and signal-plus-noise trials (set at 50, 250, and 500) for each of three typical ROC curves. For the significance test involving only one ROC curve, rating scale data were generated from the chance diagonal of the ROC space also. Although test performance was found to be somewhat dependent on the number of trials and on the location of the ROC curve in the ROC space, comparisons of the obtained and expected fractions of (falsely) significant results at various α levels showed the proposed statistical significance tests to be reliable under practical experimental conditions.     

A set-theoretic random utility model of choice behavior

A random utility model of choice was developed by combining the basic ideas of the well-known theories of Thurstone and Restle. The new model has exactly the same number of free parameters as Tversky's Elimination-by-Aspects model. Furthermore, both models were found to fit, with equal accuracy, the data reported by Rumelhart and Greeno, and Tversky. It was concluded that although the two theories are not identical, they may be difficult to discriminate empirically.     

Memory aids people use: Two interview studies

In two interview studies subjects were asked what memory aids they used and how often. In particular, the reported frequencies of use of external aids such as shopping lists and memos were compared with those of internal aids that have been investigated by psychologists, such as the method of loci. Subjects in the first study were 15 male and 15 female university students, and in the second, a group of 30 adult women, most of whom were housewives. In both studies the aids reported to be used most were external ones. However, it is pointed out that the most commonly used methods of remembering must be internal, although these are not usually considered to be aids. Some difficulties that arise in the assessment of memory in interview and questionnaire studies are discussed.     

Response class: A Guttman scale analysis

This study addressed the problem of response class as it relates to coercive child behavior. Guttman scale analyses were used to determine if there were regular, unidimensional progressions across eight coercive response categories; that children who performed high probability coercive behaviors would also tend to perform all of the lower probability coercive behaviors. Rank-order correlations were done to determine if there was consistency in the response class across settings. Two samples of boys were observed in two school settings, classroom and playground. One sample was a derivation sample of 26 boys, the second a replication sample of 27 boys. Reproducibility coefficients for the derivation sample were .92 for the classroom Guttman scale analysis and .93 for the playground analysis. For the crossvalidation sample the reproducibility coefficients were .94 in both settings. Rankorder correlations across settings and done in terms of the number of subjects performing each of the coercive responses were .971 (df=6,p<.001) for the derivation sample and .996 df=6,p<.001) for the crossvalidation sample. It was concluded that the eight coercive responses observed appeared to constitute a response class, i.e., the ordering of the responses was transitive across subjects, and that the coercive response hierarchy was stable across school settings for groups of children.I wish to extend thanks to Gerald Patterson et al., of the Oregon Social Learning Center, for their space, time, and encouragement. Special thanks to Mark Weinrott for his excellent editorial comments.     

Proportionality,linearity, and parameter constancy: Messick and Sentis reconsidered

Messick and Sentis found greater support for weak proportionality in subjects' outcome allocations (suggesting that subjects wish to maintain a constant ratio between outcomes across situations when inputs are held constant) than for constant differences between outcomes. They claimed that their data thus provided stronger support for Adams' ratio definition of equity than for Harris' linear formula. A dialogue between the two sets of authors establishes that (1) so far as their specification of fair outcomes is concerned, Adams' formula is a special case of the linear formula; (2) weak proportionality does not necessarily follow from Adams' formula and can be derived from the linear formula; (3) Adams' formula applied to subjective (rather than experimenter-defined) inputs nevertheless provides a more natural base from which to derive weak proportionality than does the linear formula in its general form; (4) excellent fits to several sets of data, including much better fit to Messick and Sentis' data than that provided by weak proportionality, are obtained if we assume that subjects use allocations which are a weighted average of those implied by Adams' formula, the Equality principle, and Komorita and Kravitz' Equal Excess Norm; and (5) a fit to Messick and Sentis' data that is almost as good as that provided by the weighted solutions model is obtained by assuming that subjects apply Adams' formula to subjective inputs and subjective outcomes that are different from the corresponding experimenter-defined values. It is agreed that the delineation of the relationships among observable properties of outcome distributions, alternative equity formulae, and different psychological processes is as important as it can be devious.