Influential observations in principal factor analysis

We propose a method for detecting influential observations in iterative principal factor analysis. For this purpose we derive the influence functionsI(x; LL ^T ) andI(x; ) for the common variance matrixT =LL ^T and the unique variance matrix , respectively, in the common factor decomposition =LL ^T + . A numerical example is given for illustration.The authors are grateful to Tomoyuki Tarumi and Atsuhiro Hayashi for their kind permission to use their software Seto/B for drawing Figures 1 and 2 and to anonymous reviewers for comments on the paper.     

Using item-specific instructional information in achievement modeling

The problem of detecting instructional sensitivity (item basis) in test items is considered. An illustration is given which shows that for tests with many biased items, traditional item bias detection schemes give a very poor assessment of bias. A new method is proposed instead. This method extends item response theory (IRT) by including item-specific auxiliary measurement information related to opportunity-to-learn. Item-specific variation in measurement relations across students with varying opportunity-to-learn is allowed for.This paper was presented at the 1987 AERA meeting in Washington, DC. This research was supported by grant OERI-G-86-003 from the Office of Educational Research and Improvement, Department of Education. The author thanks Michael Hollis and Chih-fen Kao for valuable research assistance, and appreciates valuable comments made by an anonymous reviewer.     

Social anxiety and fear of bodily sensations in panic disorder and agoraphobia: A matched comparison

This study tests the hypothesis that social anxiety and fear of bodily sensations are associated with the development of agoraphobic avoidance behavior in panic disorder patients. Twenty patients with panic disorder were compared to 20 patients with panic disorder with agoraphobia, matched by sex and duration of disorder. The two groups did not differ on measures of fear and frequency of assertive social responses. However, the agoraphobics scored higher on measures of interpersonal sensitivity, depression, feelings of inadequacy, and hostility. They also reported higher fear of bodily sensations. Although definitive conclusions need to be postponed until prospective studies have been conducted, there is evidence suggesting that the development of agoraphobia in panic patients is associated with hypersensitivity to bodily sensations and interpersonal situations.This research was supported by Grant 560-268-009 of the Dutch Organization for Scientific Research.     

Assessing the relationship of Type A beliefs to cardiovascular disease risk and psychosocial distress

Investigators have begun to take a multimodal approach to the assessment and treatment of psychosocial risk factors for cardiovascular disease (CVD). For instance, cognitive responses have become the focus of contemporary research along with continued examination of overt Type A behaviors. Price (1982) has outlined a set of beliefs purportedly associated with Type A behavior and subsequent CVD risk. The current study examines the validity of this belief set as represented by a newly developed measure, the Type A Cognitive Questionnaire (TACQ). Subjects were 221 employed adults participating in a worksite CVD risk reduction program. They completed the TACQ as part of a pretreatment CVD risk screening protocol. As hypothesized, TACQ scores were significantly associated with Type A behavior, hostility, physiological mediators of CVD, and psychosocial distress. Discussion addresses continued refinement of the Type A belief construct.     

Temporal proximity and reinforcement sensitivity in multiple schedules

Distributions of reinforcers between two components of multiple variable-interval schedules were varied over a number of conditions. Sensitivity to reinforcement, measured by the exponent of the power function relating ratios of responses in the two components to ratios of reinforcers obtained in the components, did not differ between conditions with 15-s or 60-s component durations. The failure to demonstrate the “short-component effect,” where sensitivity is high for short components, was consistent with reanalysis of previous data. With 60-s components, sensitivity to reinforcement decreased systematically with time since component alternation, and was higher in the first 15-s subinterval of the 60-s component than for the component whose total duration was 15 s. Varying component duration and sampling behavior at different times since component transition may not be equivalent ways of examining the effects of average temporal distance between components.     

A NEUROBIOLOGICAL ALTERNATIVE TO THE PERCEPTUAL REINFORCEMENT HYPOTHESIS OF STEREOTYPED BEHAVIOR: A COMMENTARY ON “SELF-STIMULATORY BEHAVIOR AND PERCEPTUAL REINFORCEMENT”

A perceptual reinforcement theory of stereotyped movements is advanced by Lovaas, Newsom, and Hickman (1987) in an effort to integrate a number of diverse observations about the origins and maintenance of this behavior. We, in turn, argue that the theory, as presented, is logically flawed and fails to take into account important biological findings and theory concerning pathological stereotyped acts. An alternative theory, derived primarily from neurological concepts, is briefly described.     

The interaction of stimulus and reinforcer control in complex temporal discrimination.

Six pigeons were trained in a discrete-trials signal-detection procedure to discriminate between a fixed-duration stimulus (5 s or 20 s) and a set of variable durations ranging from 2.5 s to 57.5 s in steps of 5 s. For each fixed-duration stimulus, the ratio of reinforcer frequencies contingent upon reporting the fixed versus the variable stimulus was systematically manipulated. Detection performance was well controlled by both the stimulus value and the reinforcer ratio. Both the discriminability between the fixed duration and the set of variable durations, and the discriminability between the fixed duration and each of the variable durations, were independent of the reinforcer-frequency ratio when discriminability was measured as log d. The sensitivity of response bias to reinforcement-ratio changes was independent of the value of the fixed duration, but was not independent of the discriminability of the variable durations from the fixed durations. Under current models, discriminability measures in complex temporal discrimination may be independent of biasing manipulations, but bias measures are not independent of stimulus values.     

Choice between reliable and unreliable outcomes: mixed percentage-reinforcement in concurrent chains.

Pigeons' choices between alternatives that provided different percentages of reinforcement in mixed schedules were studied using the concurrent-chains procedure. In Experiment 1, the alternatives were terminal-link schedules that were equal in delay and magnitude of reinforcement, but that provided different percentages of reinforcement, with one schedule providing, reinforcement twice as reliably as the other. All pigeons preferred the more reliable schedule, and their level of preference was not systematically affected by variation in the absolute percentage values, or in the magnitude of reinforcement. In Experiment 2, preference for a schedule providing 100% reinforcement over one providing 33% reinforcement increased systematically with increases in the duration of the terminal links. In contrast, preference decreased systematically with increases in the duration of the initial links. Experiment 3 examined choice with equal percentages of reinforcement but unequal delays to reinforcement. Preference for the shorter delay to reinforcement was not systematically affected by variation in the absolute percentage of reinforcement. The overall pattern of results supported predictions based on an extension of the delay-reduction hypothesis to choice procedures involving mixed schedules of percentage reinforcement.     

A nonparametric approach for assessing latent trait unidimensionality

Assuming a nonparametric family of item response theory models, a theory-based procedure for testing the hypothesis of unidimensionality of the latent space is proposed. The asymptotic distribution of the test statistic is derived assuming unidimensionality, thereby establishing an asymptotically valid statistical test of the unidimensionality of the latent trait. Based upon a new notion of dimensionality, the test is shown to have asymptotic power 1. A 6300 trial Monte Carlo study using published item parameter estimates of widely used standardized tests indicates conservative adherence to the nominal level of significance and statistical power averaging 81 out of 100 rejections for examinee sample sizes and psychological test lengths often incurred in practice.The referees' comments were remarkably detailed and greatly enhanced the writeup and sensitized the author to certain pertinent issues. Discussions with Fritz Drasgow, Lloyd Humphreys, Dennis Jennings, Brian Junker, Robert Linn, Ratna Nandakumar, and Robin Shealy were also very useful.This research was supported by the Office of Naval Research under grant N00014-84-K-0186; NR 150-533, and by the National Science Foundation under grant DMS 85-03321.