Conditional discrimination in mentally retarded adults: the development of generalized skills.

The development of generalized conditional discrimination skills was examined in adults with retardation. Two subjects with histories of failure to acquire arbitrary matching under trial-and-error procedures were successful under procedures that trained one or more prerequisite skills. The successive discrimination between the sample stimuli was established by training the subjects to name the stimuli. The simultaneous discrimination between the comparison stimuli was established using either (a) standard simple discrimination training with reversals or (b) a procedure in which each of the two sample-comparison relations in the conditional discrimination was presented in blocks of trials, with the size of the blocks decreasing gradually until sample presentation was randomized. The amount of prerequisite training required varied across subjects and across successive conditional discriminations. After acquiring either two or three conditional discriminations with component training, both subjects learned new conditional discriminations under trial-and-error procedures. In general, each successive conditional discrimination was acquired more rapidly. Tests showed that conditional responding had become a generalized skill. Symmetry was shown for almost all trained relations. Symmetry trial samples were ultimately named the same as the stimuli to which they were related in training.     

On Green's best linear composites with a specified structure,and oblique estimates of factor scores

Green solved the problem of least-squares estimation of several criteria subject to the constraint that the estimates have an arbitrary fixed covariance or correlation matrix. In the present paper an omission in Green's proof is discussed and resolved. Furthermore, it is shown that some recently published solutions for estimating oblique factor scores are special cases of Green's solution for the case of fixed covariance matrices.     

Tableau algorithms for factor analysis by instrumental variable methods

Simple tableau algorithms are given for the noniterative instrumental variable (FABIN 2) and two stage regression (FABIN 3) factor loading estimates of Hägglund. Corresponding generalized least squares estimates of factor covariances and unique variances are introduced. An example is given for the purpose of illustration and comparison.This research was supported by NSF Grant MCS-8301587.     

Effectiveness and persistence of precurrent mediating behavior in delayed matching to sample and oddity matching with children.

Two kinds of mediating behavior were compared with respect to their effectiveness in variable-delay matching-to-sample and oddity-matching tasks. Each of four 5-year-old children was trained to emit either differential or common mediating responses. The differential mediating response consisted of pressing a specific computer key corresponding to either of two possible sample stimuli (a red or a green square). The common mediating response consisted of pressing one of the two response keys regardless of the sample. The differential-response subjects did not show the typical, delay-related decrease in matching-to-sample performance that characterized the behavior of common-response subjects. An oddity-matching task was then introduced, and subjects were instructed to use the mediating keys however they preferred, including not at all. Differential-response subjects continued to respond on the originally trained mediating keys in response to sample presentation and later reversed their choice responding, thus accommodating the oddity-matching requirements. Common-response subjects continued to emit the previously trained mediating response and experienced limited success in oddity matching. Results were interpreted in terms of stimulus control, instructional control, and experimental history.     

Quantification of the effects of chlorpromazine on performance under delayed matching to sample in pigeons.

The effects of four doses of chlorpromazine (dose range 0.5 to 12.5 mg/kg) on performance under a delayed matching-to-sample procedure in pigeons was investigated, using the exponential model of memory (White, 1985). Performance was measured using a bias-free measure of discriminability, log d (Davison & Tustin, 1978), and negative exponential functions were fitted to individual-subject and group data at each dose level. A decrease in matching accuracy was found to be caused by an increase in the rate of forgetting, b, and a decrease in the initial discriminability, log d0. Changes in rate of forgetting and discriminability occurred at doses that had no statistically significant effect on response latency. The exponential model of memory accounted well for the data and provided a useful way of quantifying the effects of chlorpromazine on the processes involved in delayed matching-to-sample performance.     

Weighted minimum trace factor analysis

In the last decade several authors discussed the so-called minimum trace factor analysis (MTFA), which provides the greatest lower bound (g.l.b.) to reliability. However, the MTFA fails to be scale free. In this paper we propose to solve the scale problem by maximization of the g.l.b. as the function of weights. Closely related to the primal problem of the g.l.b. maximization is the dual problem. We investigate the primal and dual problems utilizing convex analysis techniques. The asymptotic distribution of the maximal g.l.b. is obtained provided the population covariance matrix satisfies sone uniqueness and regularity assumptions. Finally we outline computational algorithms and consider numerical examples.I wish to express my gratitude to Dr. A. Melkman for the idea of theorem 3.3.     

Reductions in anxiety and improvements in teaching associated with cue-controlled relaxation training

This study examined the efficacy of cue-controlled relaxation, taught in three 2-hour workshops, in reducing the anxiety of two elementary school teachers. Anxiety was measured using direct observation of external behavior and self-report of internal states; and the effects of anxiety reduction on selected teaching behaviors were also examined. Following training, both teachers exhibited significant reductions in motoric manifestations of anxiety and in some self-reported internal states. Both teachers showed significant increases in rewarding behavior, and they reduced disapproving behavior to zero on most days. Even though results were not maintained following the treatment program, this study demonstrated that training in the self-management of stress and tension can significantly affect the anxiety and teaching behaviors of teachers.     

The relationship between differential stimulus relatedness and implicit measure effect sizes

Implicit measures have been hypothesized to allow researchers to ascertain the existence and strength of relations between stimuli, often in the context of research on attitudes. However, little controlled behavioral research has focused on whether stimulus relations, and the degree of relatedness within such relations, are indexed by implicit measures. The current study examined this issue using a behavior‐analytic implicit‐style stimulus relation indexing procedure known as the Function Acquisition Speed Test (FAST). Using a matching‐to‐sample (MTS) procedure to train stimulus equivalence relations between nonsense syllables, the number of iterations of the procedure was varied across groups of participants, hence controlling stimulus relatedness in the resulting equivalence relations. Following final exposure to the MTS procedure, participants completed a FAST. Another group of participants was exposed to a FAST procedure with word pairs of known relatedness. Results showed that increasing relatedness resulted in a linear increase in FAST effect size. These results provide the first direct empirical support for a key process‐level assumption of the implicit literature, and offer a behavior‐analytic paradigm within which to understand these effects. These results also suggest that the FAST may be a viable procedure for the quantification of emergent stimulus relations in stimulus equivalence training.     

Acquisition of arbitrary conditional discriminations by young normally developing children

Three experiments investigated conditions designed to facilitate acquisition of arbitrary conditional discriminations in 3- to 6-year-old normally developing children. In Experiment 1, 6 subjects failed to master the arbitrary match-to-sample task under conditions of differential reinforcement alone, but 7 subjects did so when instructions or instructions and sample naming were added. In Experiment 2, sample naming introduced in a blocked-trial arrangement resulted in acquisition, but only when the sample name was a nonsense syllable provided by the experimenter (5 of 7 subjects) and not when the sample name was generated by the subject (0 of 5 subjects). Experiment 3 demonstrated the effectiveness of a training sequence involving thematically related stimuli as an intermediate step facilitating the transition from identity to novel arbitrary relations. The difficulties in mastering arbitrary conditional discriminations shown here imply that further analyses with young children will be particularly important in efforts to investigate the development of theoretically important stimulus relations.     

The Maudsley Obsessional-Compulsive Inventory and OCD in a Norwegian nonclinical sample

The 30 item Maudsley Obsessional-Compulsive Inventory (MOCI) was given to 294 under graduate students. The inventory achieved an acceptable internal consistence, but somewhat low reliability. There were no sex difference in total MOCI score, or in any of the subscales. 31% of the variance seemed to be explained by item 18: "attending too much to details", and more than 65% of the variance is explained by the checking subscale. The data give some interesting indications of the prevalence of OCD in the population.