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 simple encoding and recording system for small group observation

A simple and inexpensive system for coding and recording interaction patterns in small groups is described. It consists of a keyboard and a standard tape recorder, and it is capable of storing sequential data using up to 36 codes. Its main application is in the study of speaker-target patterns, but it can also be used in encoding up to 12 behavioral codes, or six speakers and 6 codes. The keyboard costs less than $200 and is used with conventional tape recorders and minicomputers available at most research sites.     

Syntactic influences on stuttering in young child stutterers

This study examined the location and rate of stuttering in the spontaneous speech of nine young stutterers (4.0–6.6 yr) in relation to certain aspects of syntax. It was designed to answer the following questions: Is there more stuttering at clause onset (boundary) than at other points in the clause? Does the type of clause influence rate of stuttering? Is there more stuttering on complex than on simple sentences? The syntactic analysis defined 10 clause types (seven pertaining to complex sentences and three pertaining to simple sentences); clause boundaries (taking into account “filler” words occuring in such positions); and hierarchical constituent structure within sentences. Stuttering was found with significantly greater frequency at clause boundaries than at internal (nonboundary) positions of clauses. This was apparent for nine of the 10 clause types, the exception being complement clauses. The word “and” at the beginning of simple and complex sentences provoked a high rate of stuttering. The hierarchical structure within the clause did not influence the location of stuttering, and sentence complexity was not a factor in the rate of stuttering.     

Correlation of Frostig visual perception scores and verbal IQs among epileptic children

In a large study of the visual-perceptual deficits of epileptic children both Frostig's Developmental Test of Visual Perception and the verbal part of the German version of the WISC were administered. All WISC subtests correlated significantly with the Frostig Perceptual Quotients. Verbal IQs correlated significantly with scaled scores of all the Frostig subtests. From the results of this pilot study it was suggested that intellectual abilities of epileptic children as measured by the verbal WISC and visual perception as measured by the Frostig are both influenced by the same contingencies.     

The effects of reward on tutor's behaviors in a cross-age tutoring context

Utilizing a cross-age tutoring context, this study examined the effects of reward on the teaching behaviors of the tutor, the tutor's subsequent motivation to continue to teach during a free choice period, and the social interaction between a tutor and a tutee. Third-grade boys and girls (n = 96) who exhibited a positive reinforcement style were asked to teach six addition problems to a first-grade boy or girl (n = 96). The children were randomly assigned to pairs and to one of the three reward conditions. In the performance-contingent reward condition, the tutors were promised a toy if the first-grader learned all of the arithmetic problems. In the noncontingent reward condition, the tutors were promised a toy for teaching the first-grader. In the no reward condition, the tutors taught the first-grader without promise of a toy. The results indicated that the social interaction was rated lower for the children in the performance-contingent group and that the tutors in this group spent less time teaching during the free choice period. However, neither the tutor's teaching style nor the tutee's post-test performance was adversely affected by the reward.     

Personal meaning as therapy: The roots and branches of Frankl's psychology

In recent years, Victor E. Frankl, the Viennese psychiatrist who is the founder of what has come to be known as the Third Viennese School of Psychology — Freud and Adler constituting the founders of the other two schools — has emerged as the leading proponent in psychotherapeutic circles of the centrality of the experience of “meaning” in mental health.” The goal of human life, argues Frankl, is to find meaning and order in the world for “me” personally and “us” collectively — both as an individual and a social sense of purpose and orderliness of the inner and outer environment. This paper attempts to identify—within the framework of the Jewish mystical tradition — the sources and origins of Frankl's scientific constructs in psychotherapy, and their manifestations in psychoreligious therapeutics.     

A method for identifying eggs laid by individual birds

A method for identifying eggs laid by different subsections or individual members of groups of domestic hens is described. Fat-soluble dyes are placed in gelatin capsules and fed to selected birds. These dyes produce discrete colored bands in the yolks of eggs laid by those birds. The presence of dye in eggs can be detected through the shell, and different patterns of rings can be distinguished by boiling and sectioning eggs. Application of the method to other species and other circumstances is considered.     

Rorschach assessment of purging and nonpurging bulimics

Research in bulimia has flourished in recent years, and yet minimal attention has been devoted to explorations of the bulimic's basic personality organization. We utilized the Rorschach to differentiate between purging and nonpurging bulimics and controls. There were 15 subjects in each group. The Comprehensive System (Exner, 1986) was used for the scoring of the protocols. Statistically significant differences were not found between the two bulimia groups, but interesting trends were detected in the areas of depression, anger, and self-preoccupation. Results appear to be constrained by the low rate of purging behavior. Comparisons between the combined bulimia groups and the controls resulted in solidly characterizing the bulimics as displaying perceptual inaccuracies, disordered thinking, a vulnerability to interpersonal problems, a damaged self-image, and a pessimistic outlook. The strengths of the study were its use of the Diagnostic and Statistical Manual of Mental Disorders (3rd ed., rev. [DSM-III-R]; American Psychiatric Association, 1987) nonpatients bulimic subtypes and a control group that was comparable in terms of demographics. Future Rorschach studies with bulimics displaying higher frequencies of binging and purging behaviors are suggested.     

Metalinguistic awareness and language development

Thirty-six 3- and 4-year-old children were given a battery of six metalinguistic tasks and two measures of language development: the Peabody Picture Vocabulary Test and a sentence comprehension test. The results clearly showed that the majority of preschoolers were able to make at least some metalinguistic judgments, and that metalinguistic performance improved with age. Furthermore, overall performance on the metalinguistic tasks was significantly correlated with each language measure when the effects of age were partialed out. In contrast, the correlation between age and metalinguistic performance was not significant once the effects of both language measures were partialed out. These data demonstrate that preschoolers' metalinguistic abilities are more extensive than has been previously acknowledged, and that they are closely tied to other aspects of language development at this time.