Detection theory,micromatching, and the constant-ratio rule

The conformance of detection theory and micromatching with the constant-ratio rule (CRR) was determined by calculations for sets of three stimuli and subsets of two stimuli. For an arbitrary selection of sets, the CRR would be expected to hold quite well if either detection theory or micromatching lay behind the responses. For specific stimulus configurations, however, detection theory and micromatching differ considerably from one another and from the CRR. These configurations are found particularly for the univariate distributions, and this corresponds to empirical findings that the CRR holds better for multidimensional than for unidimensional stimuli. It is shown how the differences between the three theories in the implied constancies of ratios can be used in diagnosis of the basis ofempirical confusion matrices.     

Single-trace fragility theory of memory dynamics

In single-trace fragility theory, forgetting is produced by two factors, time and interference. Memory traces are assumed to have two partially coupled dynamic properties, strength and fragility. Strength determines the probability of correct recall and recognition, while fragility determines the susceptibility of the trace to the time-decay process but not to the interference process. Consolidation is assumed to be a continual reduction in the fragility of the memory trace rather than any change in strength or availability. Decreasing fragility accounts for the continually decreasing forgetting rate, the temporal character of retrograde amnesia and recovery therefrom, and the type of internal clock necessary for nonassociative recency judgments. Data are presented to indicate that interference is independent of the interval between original and interpolated learning, that nonassociative recency discriminability approaches a limit at about 30 min, and that the decay rate of long-term retention in amnesic patients is the same as in normal Ss.     

The roles of practice and correction in the categorization of sour and bitter taste qualities

Ten Ss were selected from a group of 40 screened to determine misnaming of stimuli usually called sour (hydrochloric and citric acid) and bitter (quinine sulfate). The 10 Ss were then given 16 trials in which they were asked to match the stimuli to standards, with or without verbal feedback for each stimulus. This was followed by 16 trials without feedback for all Ss and, several days later, by a 16-trial posttest. Final improved performance of the Ss was not affected by having received the feedback. It was concluded that experience with the stimuli leads to a reduction in the degree of misnaming, implying a nonphysiological basis for sour-bitter confusions.     

Factor analysis of the army air forces sheppard field battery of experimental aptitude tests

A factor analysis was made of 39 experimental printed aptitude tests and seven reference tests selected from the Army Air Forces Aircrew Classification Battery. Thirteen factors were extracted and two independent orthogonal rotational solutions were completed. Twelve factors were interpreted. Of these, seven were clearly identifiable with previously known factors: numerical, perceptual-speed, spatial-relations, visualization, visual-memory, paired-associates-memory, and length-estimation factors. A planning factor was not as clearly identifiable. A reasoning factor was probably a composite of two or more factors that failed to separate. A new factor possibly has to do with orientation with respect to the points of the compass. Two factors were doublets, each apparently specific to one kind of test. Better conceptions were gained of the spatial-relations and visualization factors and of the kinds of tests that measure them best. Efforts to improve measures of unique factors were not uniformly successful. The attempt to duplicate a psychomotor test rather directly by analogy in printed form failed almost completely.For support of a large part of the investigation the senior author is indebted to the Social Sciences Research Council for a grant-in-aid. Dr. Fruchter supervised the computational work in the extraction of factors and in one of the rotational solutions. Much of the work was done while he was employed by the Air Training Command Human Resources Research Center. While the opinions and conclusions are those of the authors, they wish to express their appreciation to that organization and especially to Dr. John T. Dailey for making the facilities possible and to Mr. William B. Lecznar for technical and computational assistance.     

A simple graphical method for orthogonal rotation of axes

A simple method of making orthogonal rotations by projecting coordinates from one plot to another is presented. An easily constructed apparatus for rapid and accurate work is described in detail. By the technique proposed 12 to 15 rotations of pairs of axes involving 20 test variables can be completed per hour by a practiced technician.     

Individual and combined effects of noncontingent reinforcement and response blocking on automatically reinforced problem behavior

Noncontingent reinforcement (NCR) and response blocking are 2 common interventions for problem behavior maintained by automatic reinforcement. We implemented NCR and blocking with 1 boy and found this combined intervention to be effective at decreasing high rates of automatically reinforced pica. With another child, we compared the effects of blocking alone to the combined intervention. With the third child, we compared NCR alone and blocking alone to the combined intervention. Results showed that the combined intervention was effective at reducing automatically reinforced problem behavior while moderate to high levels of item engagement maintained. When evaluated individually, neither NCR nor blocking was sufficient to reduce problem behavior to clinically significant levels.