Zero correlations among tests of intellectual abilities.

It is often asserted that intercorrelations among tests of intellectual abilities are almost always positive, justifying the belief in a "g" factor and supporting the choice for oblique rotations of axes in factor analyses. Empirical information is presented from correlation matrices obtained in 13 typical analyses of intellectual measures showing that among more than 7000 correlation coefficients, 17-24% can be considered to be 0. It is estimated that under optimal conditions, when there are 15 factors, as few as 11% would need to be 0 to determine a clear, orthogonal simple structure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A three-factor model encompassing many possible statistical tests on independent groups.

Combined 3 factors, parameter used, technique used, and method of control of Type I errors, into a model that includes 100 different statistical tests, of which 64 are defensible. Tests on complex hypotheses about correlations, ρ, proportions, P, and variances, ?–2, comparable to tests on means, μ, are available. For the equal n case, the statistics needed can all be formulated either as t statistics or as omnibus F statistics. The technique factor with 5 levels includes 3 variations whereby a t is contrasted with 1 of 3 critical values appropriate for a given set of contrasts. The F statistic may be used on 1-way or multifactor designs on any of the above parameters. The experiment's design and experimental hypotheses dictate which cells of the crossing of these 2 factors are appropriate. The experimenter's major choice is the method of control of Type I errors. A simultaneous and 4 stepwise methods are discussed as general methods that could be used with most statistics. Setting alpha as the familywise rate of Type I errors and the use of simultaneous methods are recommended. (38 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Applications of standard error estimates in unrestricted factor analysis: Significance tests for factor loadings and correlations.

Estimates of standard errors of factor loadings and factor correlations in the unrestricted factor analysis model can be computed for oblique or orthogonal solutions under maximum likelihood. This information can be used to test individual coefficients for significance, to evaluate whether an orthogonal or oblique structure is most consistent with sample data, or to compute confidence intervals for single parameters or confidence regions for arbitrary groups of coefficients. Because the number of parameters estimated in factor analysis is approximately the product of number of variables multiplied by number of factors, a Bonferroni correction for the critical point of the individual test statistics is recommended to control the probability of a Type I error. Several examples are presented. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Allowing for correlations between correlations in random-effects meta-analysis of correlation matrices.

Practical meta-analysis of correlation matrices generally ignores covariances (and hence correlations) between correlation estimates. The authors consider various methods for allowing for covariances, including generalized least squares, maximum marginal likelihood, and Bayesian approaches, illustrated using a 6-dimensional response in a series of psychological studies concerning prediction of exercise behavior change. Quantities of interest include the overall population mean correlation matrix, the contrast between the mean correlations, the predicted correlation matrix in a new study, and the conflict between the existing studies and a new correlation matrix. The authors conclude that accounting for correlations between correlations is unnecessary when interested in individual correlations but potentially important if concerned with a composite measure involving 2 or more correlations. A simulation study indicates the asymptotic normal assumption appears reasonable. Because of potential instability in the generalized least squares methods, they recommend a model-based approach, either the maximum marginal likelihood approach or a full Bayesian analysis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Two many assumptions.

Responds to M. Kotkin and C. Daviet"s comments (see record 1999-15532-010) on the present author"s criticisms of the 1994 Consumer Reports study of consumers" views on mental health services (see record 1996-13324-001). Kotkin and Daviet suggested that the present author misrepresented the sampling procedure by using an incorrect percentage rate. The present author argues that both rates are literally correct given the different denominators used. He further comments that a convincing case could be made that neither figure gives a very helpful picture of the use of mental health professionals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On Thomas's model for kinship correlations.

Critically assesses H. Thomas's (1975) analysis of IQ kinship correlations. Thomas's estimation method is found to be defective because of an indeterminancy in the parameterization of his model. A simple alternative is provided. The assumptions of his model are found to be implausible. Information on genetic and environmental parameters can be extracted from IQ kinship correlations only when numerous arbitrary assumptions are made. It is concluded that "the task of estimating genetic and environment parameters from kinship correlations is hopeless." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Meta-analytic interval estimation for bivariate correlations.

The currently available meta-analytic methods for correlations have restrictive assumptions. The fixed-effects methods assume equal population correlations and exhibit poor performance under correlation heterogeneity. The random-effects methods do not assume correlation homogeneity but are based on an equally unrealistic assumption that the selected studies are a random sample from a well-defined superpopulation of study populations. The random-effects methods can accommodate correlation heterogeneity, but these methods do not perform properly in typical applications where the studies are nonrandomly selected. A new fixed-effects meta-analytic confidence interval for bivariate correlations is proposed that is easy to compute and performs well under correlation heterogeneity and nonrandomly selected studies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Within-groups correlations and their correction for attenuation.

"Situations frequently occur in which an investigator obtains the correlations between the same two variables in several groups of subjects and wants to obtain some over-all estimate of the degree of correlation between the two variables." Several techniques for evaluating such statistical problems are presented. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Correction for variance restriction in point-biserial correlations.

A correction procedure is proposed for adjusting point-biserial correlations for attenuation produced by inopportune splits in the dichotomous variable. The correction procedure permits estimation of the point-biserial correlation that would have been seen had equal proportions been present. Monte Carlo simulation evidence is provided for the accuracy of the correction procedure. Also, an example is provided from the employee turnover literature to illustrate how the correction procedure may be used. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Unsquared genetic correlations.

Demonstrates that correlations commonly used to provide an estimate of the ratio of genotypic to phenotypic variance require restrictive (and probably unreasonable) assumptions. When these assumptions are violated, the correlation in question will provide a biased estimate of the desired ratio. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cornucopia of correlations.

A table provides a compilation of miscellaneous correlations representing relationships in the real world. Included are correlations between IQ and school achievement, school achievement and other variables (e.g., motivation, self-concept, memory), and maternal and child behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Testing correlated correlations.

Tests for the equality of independent correlations are well-established in the literature, as are tests for the equality of 2 dependent correlations. However, tests for the equality of more than 2 dependent correlations seem not to have been studied. Motivated by a particular set concerning blood pressure for 3 cohorts, we provide large sample tests and related confidence regions for dealing with hypotheses concerning correlated correlations arising from a multivariate normal model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conditions for administering creativity tests.

Reviews research relating to the testing conditions under which open-ended creativity tests are administered. M. A. Wallach and N. Kogan's (1965) influential arguments as the necessity for untimed game-like conditions are outlined and criticized. Conditions other than the untimed game-like condition are found to be unsatisfactory alternatives to the timed test-like condition. Finally, criteria for assessing the adequacy of various conditions are outlined. It is concluded that there is little evidence against using timed test-like conditions as the norm for administering creativity tests. (88 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Randomization tests for predicted trends.

Argues that randomization tests can utilize a predicted trend to increase their power, much as a predicted direction of difference is incorporated into a t test to increase its power. The tests permit very specific predictions and consequently are quite powerful when the predictions have a firm basis. Randomization tests for linear and quadratic trends are described. Comparisons of probability values given by analysis of variance with those of a randomization test sensitive to quadratic U-shaped trends are provided for actual research data, to indicate the power of the randomization tests for trend. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The many faces of literacy.

Reviews the book, Literacy, language, and learning by D. R. Olson, N. Torrance, and A. Hildyard (1985). Literacy, Language, and Learning has something to offer all students of language. Its breadth is achieved through an interdisciplinary analysis of both written and spoken forms of language. The focus is on the differences between these two language modalities and on the impact, on both society and the individual, of acquiring reading and writing skills. In a very real sense the book highlights the embarrassingly narrow appreciation of language shown by much work in cognitive psychology, particularly the work using an information processing orientation. This book has no lack of breadth, yet offers considerable depth of analysis in many chapters. Arguments are well supported with research and historical findings. The book is not particularly easy to read, but it is worth the effort, in this reader's view. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Further evidence for feature correlations in semantic memory.

The role of feature correlations in semantic memory is a central issue in conceptual representation. In 2 versions of the feature verification task, participants were faster to verify that a feature () is part of a concept (grapefruit) if it is strongly rather than weakly intercorrelated with the other features of that concept. Contrasting interactions between feature correlations and stimulus onset asynchrony were found when the concept versus the feature was presented first. An attractor network model of word meaning that naturally learns and uses feature correlations predicted those interactions. This research provides further evidence that semantic memory includes implicitly learned statistical knowledge of feature relationships, in contrast to theories such as spreading activation networks, in which feature correlations play no role. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

My many mistakes with microcomputers.

Advises potential computer purchasers to carefully research systems before purchase, avoid kits, buy fully integrated systems, arrange to share software, select the appropriate technology, and ensure that adequate support and maintenance services are available for the system. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Many voices, many selves.

Reviews the book, Invisible guests: The development of imaginal dialogues by Mary Watkins (see record 1986-98003-000). Watkins seeks to convince the reader that the dialogues we carry on silently—"with our reflection in the mirror...with a figure from a dream or movie, with our dog...with critics, with our mothers, with our god(s)..."—are not an incidental aspect of mental life but central phenomena, laden with both cognitive and emotional significance. Agreement with this beginning point commits the reader to two further ideas which are conceptually independent but systematically interwoven in this book: that the imaginative life deserves analysis based on appreciation of its centrality and generative nature, and that dialogue is a fundamental—perhaps the primary—form in which we think. Watkins draws upon a range of sources in psychology, philosophy, literature and religion to develop an integrated and original interpretation of the meanings of imaginal dialogue in mental life. Readers may take issue with one or another theme, or with Watkins' overall approach, but they will find themselves engaged in a meaningful and thought-provoking dialogue. (PsycINFO Database Record (c) 2010 APA, all rights reserved)