An empirical comparison of several interval estimation procedures for coefficient alpha

Following a general introduction to Tukey's Jackknife technique and the construction of approximate confidence intervals, ten variants of the procedure are defined for giving interval estimates for coefficient alpha. A data base of known population characteristics was generated and used to compare the robustness of the ten Jackknife alternatives with Feldt's well-known sampling theory based upon the assumptions of normality. The empirical results indicate that out of the ten variants, defined by five transformations and two methods of data subdivision, only two are justifiable competitors to Feldt's approach.     

Variations in the training parameters of an avoidance conditioning paradigm and their effects on the acquisition and performance

Albino rats were trained in a delayed discriminated conditional avoidance response (CAR) to study the possible effects of varying the various training parameters,viz., the CS-UCS interval, the stimulus and strength of the inter-trial and intersession intervals on the acquisition and performance of the CAR. The response latency (RL) was related to the CS-UCS interval in a serial trend while there were response failures (ER%) at both extremes. The efficiency of the CAR were also varied according to the stimulus strength, improving up to 2 mA intensities and declining thereafter. The CAR deteriorated, as reflected in increased magnitudes of RL and ER%, with increasing intertriai intervals of 4 min or more, both in trained and trainee rats, but was not significantly affected by increasing intersession intervals unless it was 7 days or above. These findings are discussed in the light of the known principles of classical conditioning as well as of electrophysiological findings from instrumental animal conditioning studies.     

Methodological examination of the PEST (parametric estimation by sequential testing) procedure: II

Finite-state Markov sequences were constructed by a small digital computer, translated to interval-coded electrical pulse trains, and converted to sound. An adaptive stimulus programming procedure of variable step size, PEST, was employed to obtain interstate interval thresholds as a function of restrictions upon the internal structure of the sequences. These thresholds are not independent of the exit criterion for the adaptive procedure. An interactive approach is suggested for determining the exit criterion in order to protect the data against arbitrary decisions made by the E.     

A microcomputer-based tracking task for examination of the spatial and temporal organization of perceptual motor skill

A microcomputer-based tracking task is described in detail. The program that controls this task was written in Pascal and 6502 assembler language and was designed to run on an Apple IIe computer. The program was designed to allow the experimenter to vary such parameters as the velocity of the stimulus signal. In addition, several indicants of performance are recorded simultaneously and are averaged over selected time intervals during each trial. The paper also illustrates the applications of this particular computer program in the study of motor control and learning.     

Cautions regarding random number generation on the Apple II

Undocumented characteristics of the pseudorandom number generators in Applesoft BASIC and Apple Pascal are described that cause identical sequences to be generated on different executions of programs written in those languages. Although it is relatively easy for this problem to escape notice, in both cases the problem is easily corrected once its existence is known.     

Bedding preferences of pregnant laboratory-reared mice

Pregnant ARS Ha (ICR) Swiss mice were allowed to select from 10 commercially available bedding products for parturition and rearing young. Combinations of bedding materials were most often selected. Products of wood origin were overwhelmingly preferred. Rates for the selection of bedding materials from the 20 tests were Aspen Bed 100%, Cedar Shavings 75%, Pinewood Shavings 45%, Ab-Sorb-Dri 5%, and Stop “O” 5%.     

The effects of environmental support and secondary tasks on visuospatial working memory

In the present experiments, we examined the effects of environmental support on participants’ ability to rehearse locations and the role of such support in the effects of secondary tasks on memory span. In Experiment 1, the duration of interitem intervals and the presence of environmental support for visuospatial rehearsal (i.e., the array of possible memory locations) during the interitem intervals were both manipulated across four tasks. When support was provided, memory spans increased as the interitem interval durations increased, consistent with the hypothesis that environmental support facilitates rehearsal. In contrast, when environmental support was not provided, spans decreased as the duration of the interitem intervals increased, consistent with the hypothesis that visuospatial memory representations decay when rehearsal is impeded. In Experiment 2, the ratio of interitem interval duration to intertrial interval duration was kept the same on all four tasks, in order to hold temporal distinctiveness constant, yet forgetting was still observed in the absence of environmental support, consistent with the decay hypothesis. In Experiment 3, the effects of impeding rehearsal were compared to the effects of verbal and visuospatial secondary processing tasks. Forgetting of locations was greater when presentation of to-be-remembered locations alternated with the performance of a secondary task than when rehearsal was impeded by the absence of environmental support. The greatest forgetting occurred when a secondary task required the processing visuospatial information, suggesting that in addition to decay, both domain-specific and domain-general effects contribute to forgetting on visuospatial working memory tasks.     

Spacing effects in picture memory

Three experiments were conducted to capitalize on the conclusion of Shaffer and Shiffrin (1972) that complex visual scenes are not rehearsed in testing the hypothesis that the effect of spacing on memory is due to rehearsal. In Experiment I, a list of vacation slides was presented in which both the number of repetitions and the spacing of repetitions were varied. Subsequent frequency judgments showed an effect of spacing much like that found using verbal materials. In Experiments II and III, effects of filled and unfilled spacing intervals were compared, and it was concluded that the spacing effect is primarily a function of the duration of the spacing interval. No evidence was found to support the notion that pictures are rehearsed. Rehearsal apparently cannot play the key role in an adequate, completely general explanation of the spacing effect.     

Understanding Middle School Students’ Physical Activity and Health-Related Quality of Life: An Expectancy-Value Perspective

Assessing and promoting physical activity and health-related quality of life (HRQOL) have become major public health issues, but little is known regarding HRQOL and its relation with physical activity in adolescents. This study attempted to examine relationships among middle school students’ motivation, physical activity, and HRQOL by using the expectancy-value model as a theoretical framework. Participants were 282 middle school students who responded to a previously validated inventory assessing their motivation, physical activity, and HRQOL. Correlation analyses revealed that expectancy-related beliefs and task values were positively related to physical activity and HRQOL. Physical activity was positively associated with physical, emotional, and social functioning of HRQOL. Regression analyses showed a significant relationship between increasing expectancy-related beliefs and increasing degrees of HRQOL. This research line is promising in that it can provide useful information regarding the translation of theory to practice in influencing adolescents’ physical activity and HRQOL.     

Implementation of a Self-monitoring Application to Improve On-Task Behavior: A High-School Pilot Study

Technological innovations offer promise for improving intervention implementation in secondary, inclusive classrooms. A withdrawal design was employed with two high-school students in order to assess the effectiveness of a technologically delivered, self-monitoring intervention in improving on-task behavior in a science classroom. Two students ages 14 and 15 with diagnoses of specific learning disability (Student 1) and attention deficit hyperactivity disorder (ADHD; Student 2) were selected by case manager referral due to difficulties with on-task behavior despite long-term administration of psychostimulant medication. After baseline data were collected, both students were trained in the use of a self-monitoring application (I-Connect) delivered via a handheld tablet. On-task prompts were delivered at 5-min intervals in an ABAB withdrawal design. The intervention resulted in positive, stable improvements in the primary dependent variable of on-task behavior for both students and less clear improvement in the generalization variable of disruptive behavior.     

Lexical contribution to nonword-repetition effects: Evidence from event-related potentials

Two experiments investigated the modulation of event-related potentials (ERPs) by the repetition of orthographically legal and illegal nonwords. In Experiment 1, subjects silently counted occasional words against a background of nonwords, a proportion of which were repetitions of an immediately preceding legal or illegal item. ERPs to repeated legal items showed a sustained, topographically diffuse, positive-going shift. In contrast, repeated illegal nonwords gave rise to ERPs showing a smaller and temporally more restricted positive-going modulation. In an attempt to equalize depth of processing across legal and illegal nonwords, subjects in Experiment 2 were required to count items containing a nonalphabetic character against the same background of nonword items. ERPs to repeated legal items showed a modulation similar to, although smaller than, that found in Experiment I, but no effects of repetition were observed in the ERPs to the illegal nonwords. It was concluded that the effects of repeating nonwords, at least as manifested in concurrently recorded ERPs, differ as a consequence of whether items can access lexical memory, and that this is inconsistent with the attribution of such effects solely to the operation of episodic memory processes.     

Behavior and personality assessment in men labeled adaptive sociopaths

Few efforts have been made to understand antisocial-prone individuals who maintain adaptive functioning. This study identified a sample of potentially deviant but adaptively functioning persons to determine whether they differed significantly from their more conforming peers. A small sample of men was selected by Minnesota Multiphasic Personality Inventory (MMPI)-defined criteria for sociopathy and compared with MMPI-defined normals of similar ages, backgrounds, and intelligence. Response variables were those cited in the literature as characteristic of sociopathic psychopathology and included measures of abilities to plan ahead and inhibit impulsiveness, sensation seeking, interpersonal performance and style, and behavior conformity. Men labeled adaptive sociopaths showed greater impulsiveness and needs for experience seeking, earned lower scores on measures of socialization and self-control, and admitted greater adolescent behavior deviance. They were not shown to be less empathetic or less able to relate interpersonally in interview. The potential role of socially constructive self-determined goals and tangible vocational rewards as mediators of adaptive behavior are discussed in terms of overcoming antisocial tendencies and attenuation of behavior disinhibition.     

Determinants of subjective contour: Bourdon illusions and “unbending” effects

Wenderoth and O’Connor (1987b) reported that, although matches to the straight edge of two triangles placed apex to apex revealed an apparent bending in the direction of the chevron formed by the hypotenuse pair (the Bourdon effect), no perceptual unbending of the bent chevron occurred. Using subjective contour figures, Walker and Shank (1988b) found large and approximately equal bending and unbending effects, consistent with two theories that they proposed. In Experiment 1, using adjustable chevron matching and subjective contours, we found that Bourdon effects, equivalent in magnitude to those reported by Walker and Shank, were 4–5 times larger than unbending effects. In Experiment 2, we used a variation of Walker and Shank’s measurement technique, in which subjects selected a matching angle from a graded series. We obtained Bourdon effects similar to those in Experiment 1, but much larger unbending effects. Nevertheless, Bourdon effects were significantly larger than unbending effects in one set of data; and in another, Bourdon test means were larger than unbending test means. In both data sets, there was a large and significant pretest bending effect, which enhanced the magnitude of unbending test minus pretest scores. These results were consistent with our theory but not the theories of Walker and Shank. The variance of unbending test matches, 3–4 times that of Bourdon test matches, reflected the task difficulty. We propose that subjective obtuse angle contraction that exceeds real obtuse angle contraction explains the fact that unbending effects are larger in subjective than in real contours.     

Adolescents' attitudes toward family and gender roles: An international comparison

Adolescents' attitudes toward gender and familial roles were examined using the Attitudes Toward Women Scale for Adolescents [N. L. Galambos, A. C. Petersen, M. Richards, & I. B. Gitelson (1985) “The Attitudes Toward Women Scale for Adolescents (AWSA): A Study of Reliability and Validity,” Sex Roles, Vol. 5/6, pp. 343–356] and the Historic-Sociocultural Premises scale [R. Díaz-Guerrero (1975) Psychology of the Mexican: Culture and Personality, Austin: University of Texas Press]. Participants were 265 international students (11 to 17 years of age) from 46 different countries attending schools in the Netherlands. The countries of origin were grouped into two categories of cultural values based on G. Hofstede [(1983) “Dimensions of National Cultures in Fifty Countries and Three Regions,” in J. B. Deregowski, S. Dziursawiec, & R. C. Annis (Eds.), Expiscations in Cross-Cultural Psychology, Lisse Netherlands: Swets & Zeitlinger]: Wealthier, more individualistic countries comprised Group 1 and less wealthy, more collectivist countries Group 2. Girls responded less traditionally than did boys on both scales. Students from Group 2 countries had more traditional attitudes than did students from Group 1 countries.     

Comparison of Peabody,Leiter, WISC,and academic achievement scores among emotionally disturbed children

The present study examined the utility of employing tests such as the PPVT and the AALIPS as viable alternatives to the WISC in the prediction of academic achievement with emotionally disturbed children. The three IQ instruments and the California Achievement Test were administered to a group of 50 male emotionally disturbed children. Intercorrelations among the three tests were all significant and all three successfully predicted academic achievement. However, both the PPVT and the AALIPS consistently resulted in higher IQ estimates than did the WISC. Results supported the use of the PPVT and the AALIPS as equally viable alternatives to the more comprehensive WISC.     

HyperCard administration of a block-design task

HyperCard (Atkinson, 1987) is a new development environment for the Macintosh that shows promise for use in psychological research and testing. In this paper, we discuss the development of HyperCard stackware with which a block-design task similar to that of the Wechsler Adult Intelligence Scale-Revised (WAIS-R) can be administered. The reliability and validity of the computerized block-design task was evaluated by administering both the computerized task and the WAIS-R subtest to college undergraduates. Results indicated that the computerized task’s reliability compared favorably with that of the WAIS-R subtest. Validity coefficients were equivocal; although an elapsed-time measure showed moderate correlation between the tasks, the numbers of designs correctly completed in each condition were not significantly correlated.     

CORE: Computer-controlled operant reinforcement

A Pascal-based system and software is described for computer reinforcement of operant responding (CORE). CORE allows a single microcomputer to control up to eight different work stations simultaneously, on one of several schedules. The user need not be familiar with Pascal, although modifications of the programs require a good working knowledge. The system is menu-driven and interacts with the user in a question-and-answer format. The user can select a variety of experimental parameters, for example, session and reinforcement duration, delay, and type of reinforcement schedule. During run-time, CORE provides frequently updated on-screen graphics (Cumulative Records or Interresponse Time Distributions) and counter display. Permanently stored data and information from other counters may also be displayed or printed from the disk. Presently, three programs are implemented for a variety of related reinforcement schedules (e.g., fixed ratio, variable ratio, fixed interval, variable interval, alternation).