Computing the real solutions of Fleishman's equations for simulating non-normal data

Fleishman's power method is frequently used to simulate non-normal data with a desired skewness and kurtosis. Fleishman's method requires solving a system of nonlinear equations to find the third-order polynomial weights that transform a standard normal variable into a non-normal variable with desired moments. Most users of the power method seem unaware that Fleishman's equations have multiple solutions for typical combinations of skewness and kurtosis. Furthermore, researchers lack a simple method for exploring the multiple solutions of Fleishman's equations, so most applications only consider a single solution. In this paper, we propose novel methods for finding all real-valued solutions of Fleishman's equations. Additionally, we characterize the solutions in terms of differences in higher order moments. Our theoretical analysis of the power method reveals that there typically exists two solutions of Fleishman's equations that have noteworthy differences in higher order moments. Using simulated examples, we demonstrate that these differences can have remarkable effects on the shape of the non-normal distribution, as well as the sampling distributions of statistics calculated from the data. Some considerations for choosing a solution are discussed, and some recommendations for improved reporting standards are provided.     

The development of cognitive inhibition in streams-of-consciousness and directed speech

This research examined the development of the ability to inhibit thoughts within free speech by manipulating the content requirements of overt streams-of-consciousness. A picture-naming task with procedural manipulations similar to the stream-of-consciousness task was created as an additional method of investigating the development of the inhibition of speech. Comparison of adults' performance in the two tasks indicated that mature performance reflected inhibitory processing rather than selective attention. The children's performance in the stream-of-consciousness task suggested a developmental change in their ability to produce a stream-of-consciousness overtly. An investigation of inhibition in the picture-naming task with kindergartners, second graders, fifth graders and adults revealed a developmental improvement in inhibitory ability over the middle childhood years. These results are consistent with the interpretation that developmental improvements in cognitive inhibition contribute to developmental improvements in cognitive function on a variety of tasks.     

Is preschool executive function causally related to academic achievement?

The primary objective of this study was to reevaluate the well-established result that preschoolers' performance on executive function tasks are positively associated with their performance on academic achievement tests. The current study replicated the previously established concurrent associations between children's performance on EF tasks and academic achievement tests. Specifically, children's performance on measures of inhibitory and motor control were positively associated with their performance on tests of reading, writing, and mathematics achievement (rs?=?.2?.5); moreover, although diminished in magnitude, most of these associations held up even after including an earlier measure of academic achievement as a covariate (rs?=?.1?.3). However, the application of an alternative analytic method, fixed effects analysis, a method that capitalizes on repeated measures data to control for all time stable measured and unmeasured covariates, rendered the apparent positive associations between executive function and academic achievement nonsignificant (rs?=?.0?.1). Taken together, these results suggest that the well-replicated association between executive function abilities and academic achievement may be spurious. Results are discussed with respect to the importance of utilizing analytic methods and research designs that facilitate strong causal inferences between executive function and academic achievement in early childhood, as well as the limitations of making curriculum development recommendations and/or public policy decisions based on studies that have failed to do so.     

Development of the Ability to Insert into a Series

The development of children's ability to insert an item into a series was investigated. Children ranging in age from 3 to 6 years old were given a seriation construction and insertion task, several different types of insertion tasks, and tasks in which they learned to recognize a series. Children's performance on the seriation construction and insertion task was not influenced by their experience with other tasks, and they were able to solve different types of insertion tasks by 5 years of age. The results thus support Piaget's (1965) and Halford's (1982) predictions of stage-related constraints on children's insertion skills, rather than Bullock's (1985) invariance hypothesis, which claims that experience is a more important influence.     

THE INFLUENCE OF SCHOOLING ON ADULT RECALL OF FAMILIAR STIMULI: A STUDY IN GHANA*

Several studies have shown the influence of schooling on a variety of cognitive skills. However, since the tasks employed were nearly always derived from the school setting, such findings provide no adequate answer to the following question: given a cognitive task with which schooled and unschooled subjects have had equal experience, does schooling still have an effect? Opposing views are held about this question, and the aim of the present study was to contribute towards answering it. Twenty-four schooled and 24 unschooled subjects, evenly divided by sex within each group, were given a recall task based on an indigenous game equally familiar to all of them. The task involved positions, numbers, and combinations of both. The performance of schooled subjects was very significantly superior on all aspects of the tasks. With regard to position there was an interaction indicating that women's performance was particularly enhanced by schooling, but this was not the case with numbers. Results thus support the view that schooling does have a general effect not necessarily mediated by specific experience. Moreover, in the light of the proportion of variance accounted for among different component tasks, it is suggested that a major effect of schooling might be an increased ability to process complex information.     

Slip and Trip Perturbations During an Object Transport Task Requiring a Lateral Change in Support

The ability to counteract destabilizing external forces while simultaneously executing a complex task presents a novel way to ascertain one's ability to generate adaptive postural control responses to avoid a potential fall. In this study, participants performed an upper limb object transport task requiring a lateral change in support on a robotic platform that could remain fixed in space or translated (mimicking a slip or trip perturbation). No significant stability differences were observed at initial recovery step between slip and trip perturbations. Variability measures were greatest during the trip perturbations; though stability was at its greatest level preceding these perturbations. These results will aid in the design of future studies that will investigate adaptive postural control responses generated by older adults when executing similar, ongoing complex upper body tasks interrupted by a destabilizing support surface perturbation.     

Oxytocin Receptor Gene Relates to Theory of Mind and Prosocial Behavior in Children

Individual social differences have been addressed in recent studies, and the oxytocin receptor gene (OXTR) is the major candidate in explaining various social phenotypes. To study the association between a well-known haplotype (rs53576) of OXTR and children's prosocial behavior and its relationship with theory of mind (ToM) ability, 87 children (aged 3 to 5 years old) participated in 3 prosocial tasks and ToM performance experiments. Participants who were homozygous for the G allele (GG) exhibited more prosocial behaviors than did those with 1 or 2 copies of the A allele (AA), and GG carriers also displayed better ToM ability than did AA individuals. Further tests showed differences between genotypes in helping and comforting, albeit not in sharing. The results demonstrated that OXTR rs53576 was related to individual differences in ToM and was associated with prosocial behavior.     

Advantages of difficult tasks1

If people work on a hard task before proceeding to one of intermediate difficulty, success will be relevant (predictive of future success) while failure will be irrelevant (not predictive of future failure). However, if they work first on an easy task, success will be irrelevant (not predictive of future success) while failure will be relevant (predictive of future failure). Previous research thus suggests that experience with hard tasks should always lead to more favorable evaluations of one's performance and better future performance than experience with easy tasks. The present study tested these predictions by manipulating initial expectancy (high or low), perceived difficulty of a set of practice problems (practice problems easier, harder, or equal in difficulty to those on a subsequent test), and practice problem feedback (success or failure). As predicted, experience with hard practice problems was most beneficial, regardless of the level of the feedback which students received. This was more true for males than females and for students with high ability than students with low ability.     

Do CEOs Matter to Firm Strategic Actions and Firm Performance? A Meta‐Analytic Investigation Based on Upper Echelons Theory

What roles do CEOs play in firm performance? To address this question, the management field has accumulated a substantial amount of research over the past 3 decades built on upper echelons theory (UET), which posits that CEO characteristics manifest in firm strategic actions and, in this way, future firm performance. Hence, there is a need to systematically amass and take stock of prior empirical findings for UET testing and development. We use meta‐analytic techniques to synthesize prior UET research on the relationships among commonly studied CEO characteristics, firm strategic actions, and future firm performance. Based on 308 studies, meta‐analytic results generally support UET's predictions with a few exceptions: CEO characteristics (i.e., tenure, formal education, prior career experience, and positive self‐concept) are significantly associated with firm strategic actions, which in turn are significantly related to future firm performance. Moreover, CEO characteristics (i.e., age, tenure, formal education, and prior career experience) are positively related to future firm performance. In addition, fine‐grained analyses have revealed interesting and important relationships between specific measures of CEO characteristics (e.g., CEO prior task experience) and firm outcomes (e.g., firm strategic actions that match with CEO prior task experience). Implications for theory, future research, and practice are discussed.     

Further explorations of perceptual speed abilities in the context of assessment methods, cognitive abilities, and individual differences during skill acquisition

Measures of perceptual speed ability have been shown to be an important part of assessment batteries for predicting performance on tasks and jobs that require a high level of speed and accuracy. However, traditional measures of perceptual speed ability sometimes have limited cost-effectiveness because of the requirements for administration and scoring of paper-and-pencil tests. There have also been concerns about the validity of previous computer approaches to administering perceptual speed tests (e.g., see Mead & Drasgow, 1993). The authors developed two sets of computerized perceptual speed tests, with touch-sensitive monitors, that were designed to parallel several paper-and-pencil tests. The reliability and validity of the tests were explored across three empirical studies (N = 167, 160, and 117, respectively). The final study included two criterion tasks with 4.67 and 10 hours of time-on-task practice, respectively. Results indicated that these new measures provide both high levels of reliability and substantial validity for performance on the two skill-learning tasks. Implications for research and application for computerized perceptual speed tests are discussed.     

Dynamic Spatial Ability and Psychomotor Performance

Dynamic spatial ability is one's ability to estimate when a moving object will reach a destination, or one's skill in making time-to-contact (TTC) judgments. In 2 studies, we investigated the nature of dynamic spatial ability and its role in psychomotor (PM) task performance. In the first study, 405 basic military trainees were given both spatial and nonspatial versions of TTC and comparative arrival-time tasks, and we found that the spatial and nonspatial versions of the tasks were more highly correlated than the spatial tasks were to each other, suggesting that a timing, rather than a spatial, mechanism underlies performance of dynamic spatial tasks. In the second study with 376 military trainees, we found that performance on a set of PM tasks was predicted by a general working-memory (WM) Capacity factor (r = .45) and an orthogonal Temporal Processing (TP) factor (r = .55), suggesting the importance of the dynamic spatial, or of the TP factor, in many real-world activities.     

A meta-analytic review of prospective memory and aging

A meta-analysis of prospective memory (PM) studies revealed that in laboratory settings younger participants outperform older participants on tests of both time- and event-based PM (rs=-.39 and -.34, respectively). Event-based PM tasks that impose higher levels of controlled strategic demand are associated with significantly larger age effects than event-based PM tasks that are supported by relatively more automatic processes (rs=-.40 vs. -.14, respectively). However, contrary to the prevailing view in the literature, retrospective memory as measured by free recall is associated with significantly greater age-related decline (r=-.52) than PM, and older participants perform substantially better than their younger counterparts in naturalistic PM studies (rs=.35 and.52 for event- and time-based PM, respectively).     

The effect of simultaneous versus serial responding on children's ability to coordinate two dimensions

Previous research by Lidster and Bremner (1999) on young children's ability to coordinate two dimensions has shown that performance on construction tasks (in which children have to give the correct coordinates for a point in space that is already known) is superior to performance on interpretation tasks (in which children are given a pair of coordinates and have to locate the correct point in space on the basis of these). The present study investigates the suggestion made by Lidster and Bremner that construction tasks may be easier due to the possibility that they can be solved by attending to only one dimension at a time. In this experiment 84 children between the ages of 3 and 6 years were given 16 trials of a construction task, which they were either asked to do by moving two pointers simultaneously or by moving the pointers sequentially. Overall there was no main effect of condition. However, some trials were affected by condition. These results are discussed in relation to Lidster and Bremner's suggestions and Huttenlocher, Newcombe, and Sandberg's (1994) claims regarding the development of spatial understanding.     

Social cognitive predictors of academic persistence and performance in engineering: Applicability across gender and race/ethnicity

We examined the utility of social cognitive variables in the longitudinal prediction of academic persistence and success of engineering students. The participants, 908 students enrolled in engineering majors at two state universities, completed measures of academic support, self-efficacy, outcome expectations, interests, satisfaction, positive affect, and intended persistence at the end of each of their first four semesters. In the current study, students' first and second semester responses were used to predict persistence and grade performance in engineering by the end of six semesters. Path analytic findings indicated that second-semester persistence intentions, satisfaction with the major, self-efficacy, and social support each produced direct paths to persistence. Objective ability (mathematics SAT scores), outcome expectations, and interests were linked to persistence indirectly via their relations to other variables in the model. In addition, self-efficacy and objective ability jointly predicted grade performance. Results were stable across gender and racial/ethnic groups. Implications for research and practice on academic adjustment in engineering are considered.     

ACADEA—a decision support system for faculty performance reviews

ACADEA, a multi‐criteria decision support system for the performance review of individual faculty, is presented. Developed from the point of view of a department that is facing exogenously as well as self imposed objectives, the support system looks upon the aggregate performance of an academic department as the result of individual faculty member's multi‐criteria evaluations. Five objectives, research output, teaching output, external service, internal service and cost, are operationalized into criteria. The system is applied to a university department with 30 faculty members evaluated over a 3‐year period. The results identify promotional candidates and reveal underlying problems in managerial consistency, departmental sub‐groupings and the incentive structure. The outcomes of the support system are consistent with the position that equity in faculty governance does not necessarily imply equal loads on all tasks. Copyright © 2000 John Wiley & Sons, Ltd.     

Executive function and theory of mind: Predictive relations from ages 2 to 4

Despite robust associations between children's theory of mind (ToM) and executive function (EF) skills, longitudinal studies examining this association remain scarce. In a socially diverse sample of 122 children (seen at ages 2, 3, and 4), this study examined (a) developmental stability of associations between ToM, EF, verbal ability, and social disadvantage; (b) continuity and change in ToM and EF; and (c) predictive relations between ToM and EF. Verbal ability and social disadvantage independently predicted changes in EF (but not ToM). Task scores improved with age and showed stable individual differences. The authors examined predictive relations between ToM and EF using partial correlations (controlling for age and verbal ability) and hierarchical regressions (that also controlled for social disadvantage and initial ToM and EF). The findings provide only partial support for the view that ToM is a prerequisite for EF but stronger support for the proposal that EF facilitates children's performance on ToM tasks.     

Understanding transformational leadership–employee performance links: The role of relational identification and self‐efficacy

We examined how employee perceptions of relational identification with the supervisor and self‐efficacy mediate the relationship between transformational leadership and supervisor‐rated performance. Performance is used here to refer to the individual's ability to be creative, innovative, inspiring, and take on challenging tasks to achieve organizational goals for the greater good. Using a sample of 426 employees and their 75 immediate supervisors from a large automobile dealership, hierarchical linear modelling results revealed that relational identification with the supervisor mediated the relationship between transformational leadership and self‐efficacy, which was then positively related to employee performance. Implications for future research, theory, and practice are discussed.     

PERCEPTION DE FORMES GÉOMÉTRIQUES ET d'ILLUSIONS CHEZ DES ENFANTS FRANCAIS ET AMÉRICAINS1

Perception of geometric forms and optical illusions in French and American children. — A 30-item series of perceptual problems involving geometric forms and optical illusions was administered to 357 French and 732 American children, ages 8 through 16 years. A developmental gradient was observed in both samples: performance correlated +.33 with age in the French sample and +.22 in the American. Age-by-age comparison of means gave approximately identical results, except at age 12 where the French children scored significantly higher. Prior research has shown the perceptual series to be uncorrelated with verbal and linguistic ability, but significantly related to performance on tasks (such as the embedded figures test) which reflect analytic capacity. These findings, plus the cross-national stability of age norms and developmental gradients found here, suggest that the series may have value as a research tool for cross-cultural study of interpersonal effectiveness and analytic aptitude.     

The value of relative-time-spent ratings in task-oriented job analysis

Recent studies have called for the abandonment of the relative-time-spent scale in task inventories. This recommendation is based on findings that the job profile created with the scale data is highly correlated with the profile created from a much simpler “Do you perform this task?” checklist. We examined this issue using 3 inventories and 42 jobs (N=2252). Profile correlations were computed on only the tasks actually performed by incumbents to avoid possibly inflated rs due to including irrelevant tasks. The specificity of task inventory items was proposed as an explanation for the high correlation between the two job profiles. Specificity of items was examined by looking at both the type (job duties versus tasks) and the amount (number of items in job profile and average number of items relevant to each job) of items used in the inventory. Correlations between time spent and checklist profiles were in the .80's and .90's regardless of the number of irrelevant tasks or the specificity of tasks. We agree with previous military research and conclude that the relative-time-spent scale has limited incremental utility beyond a dichotomous checklist.     

The Validity of Conscientiousness for Predicting Job Performance: A meta‐analytic test of two hypotheses

This study examined two hypotheses regarding the moderating effects of job characteristics on the validity of personality. Using meta‐analytic techniques, the authors explored the extent to which the structural characteristics and cognitive ability requirements of jobs influence the role of conscientiousness in predicting performance. The results suggest that conscientiousness is a stronger predictor of performance in jobs that are highly routinized, and a weaker predictor of performance in jobs with high levels of cognitive ability requirements. Implications for theory and future research are discussed.