On various causes of improper solutions in maximum likelihood factor analysis

In the applications of maximum likelihood factor analysis the occurrence of boundary minima instead of proper minima is no exception at all. In the past the causes of such improper solutions could not be detected. This was impossible because the matrices containing the parameters of the factor analysis model were kept positive definite. By dropping these constraints, it becomes possible to distinguish between the different causes of improper solutions. In this paper some of the most important causes are discussed and illustrated by means of artificial and empirical data.The author is indebted to H. J. Prins for stimulating and encouraging discussions.     

Treatment of obsessive-compulsive patients: The contribution of self-instructional training to the effectiveness of exposure

Fifteen obsessive-compulsive patients were given treatment consisting of ten sessions of gradual exposure in vivo. For half of the patients gradual exposure in vivo was preceded by self-instructional training.Treatment resulted in significant improvement on anxiety and avoidance scales, Leyton Obsessional Inventory, Self-rating Depression Scale and on ratings for anxious mood and depression. Neither the post-test nor the follow-ups 1 month and 6 months later indicated a difference between the effects of the two conditions. Self-instructional training did not enhance the effectiveness of gradual exposure in vivo.     

TEACHING THE HANDICAPPED TO EAT IN PUBLIC PLACES: ACQUISITION,GENERALIZATION AND MAINTENANCE OF RESTAURANT SKILLS

This study examined classroom-based instruction in restauranting skills for handicapped persons. Three male students were taught each of four skill components in sequential order: locating, ordering, paying, and eating and exiting. Training was implemented in a multiple baseline design across subjects and consisted of modeling and role playing in conjunction with photo slide sequences and a simulated ordering counter. The use of a menu containing general item classes and a finger matching procedure for identifying errors in the delivery of change greatly reduced the reading and math skills necessary to enter and complete the program. Periodic probes were conducted in a McDonald's restaurant prior to, during, and up to one-year following the termination of training. In addition, two probes (overt and covert observation) were conducted in a Burger King restaurant to assess further generalization to a location different from the one depicted throughout training. Results showed that students' performance on restaurant probes improved as a result of training, generalized to novel settings, maintained over an extended period of time, and was comparable to that of a normative sample of nonretarded persons.     

Foveal diplopia thresholds and fixation disparities

Comparison of the magnitude and intrinsic spread of foveal diplopia thresholds with the accuracy of ocular alignment as determined with a subjective alignment method shows that: the accuracy of alignment in the vertical direction (within 1–2 min) is remarkably good and much better than in the horizontal direction; the largest disparities occurring due to restricted alignment accuracy are usually substantially smaller than the foveal diplopia thresholds; interindividual variability in the magnitude of foveal diplopia thresholds is not due only to interindividual variability in the alignment accuracy; and the spread of foveal diplopia thresholds exceeds the spread of ocular alignment, which implies that the noise in the foveal disparity domain is not only due to the restricted alignment accuracy but also to sensory processes. Finally, the data confirm that, unlike the case with diplopia thresholds, the spread of stereoscopic thresholds is not affected by the restricted alignment accuracy.     

The linear utility model for optimal selection

A linear utility model is introduced for optimal selection when several subpopulations of applicants are to be distinguished. Using this model, procedures are described for obtaining optimal cutting scores in subpopulations in quota-free as well as quota-restricted selection situations. The cutting scores are optimal in the sense that they maximize the overall expected utility of the selection process. The procedures are demonstrated with empirical data.     

The EPPI family therapy outcome study

Information was evaluated from 1014 families seen in an eight-year period by therapists connected with the Department of Family Psychiatry at Eastern Pennsylvania Psychiatric Institute in Philadelphia. Statistical analysis revealed several factors that had some predictive value in relation to outcome of therapy; these were race, past psychiatric hospitalization, type of presenting family problem, and number of sessions held. There was a rather good chance of improvement being noted by the therapist if the family stayed in treatment for eight or more sessions. About 90% of the cases were seen for less than 20 interviews. Only about 3% were seen for longer than 35 interviews. The vast majority of EPPI cases were short-term. Black families tended to present different problems from white, and therapy was terminated with blacks sooner than for whites. About 35% of families terminated after one to two interviews, and another 30% after three to seven sessions. Since families tended to benefit most after eight or more sessions, the need for better methods or techniques to engage families is highlighted.The research was supported in part by a Career Development Award from the University of California, San Francisco, to the first author.     

Attitude extremity,consensus and diagnosticity

Studied the effects of attitude extremity on perceived consensus and willingness to ascribe trait terms to others with either pro or anti nuclear attitudes. Results showed that attitude extremity affected consensus estimates. Trait attributions revealed a clear effect for valence, especially for the extreme attitude groups. Subjects with extreme attitudes also ascribed more traits to both pro and anti others than subjects with relatively moderate attitudes.     

Feature-specific interference in letter identification

It is a well documented finding that letter identification may be impaired by the presence of neighboring characters. There is much less agreement about the exact nature of such lateral interference. Evidence has been obtained for feature-specific interference, and even feature-specific facilitation. Santee and Egeth (1980) suggested that feature-specific interference will mainly be observed in data-limited situations where stimuli are presented for short durations and positional uncertainty is involved. They further suggested that interference would be revealed in accuracy rather than latency measures.In our first experiment, similar exposure conditions were used to those suggested by Santee and Egeth. In a second experiment, however, a longer exposure duration was used, and latency measurements were also collected. In a third experiment, positional uncertainty was removed by foveal presentation, and with this high quality stimulus presentation only latency measurements could be obtained.In all these experiments clear evidence for feature-specific interference was found, both in accuracy and latency data, and these results also held up under the detectability/criterion analysis proposed by Estes (1982). From these findings it can be concluded that feature-specific interference occurs under a wide range of conditions, including those representative of normal reading.     

Assertive training for agoraphobics

Twenty-one unassertive agoraphobic patients were assigned to one of three treatments: (1) prolonged exposure in vivo, (2) assertive training and (3) a combination of assertive training and prolonged exposure in vivo. Each treatment was conducted in groups which were led by two therapists. Assessments involved both phobic targets and assertiveness, and were made before and after treatment, and at 1-month follow-up. Exposure in vivo was found to be superior to assertive training on phobic targets. Assertive training produced greater gains in assertiveness than exposure in vivo. The combination of treatments produced results comparable to exposure in viro. Results indicated that the type of change produced by the treatments is a rather specific one and is related to the specific target of treatment.