Capacity limitations and the detection of correlations: comment on Kareev (2000)

Y. Kareev (2000) argued that the limited capacity of working memory may be an adaptive advantage for the early detection of useful correlations. His analysis indeed suggests that the optimal sample size is close to G. A. Miller's (1956) "magical number 7 +/- 2." The authors point out logical and statistical limitations of Y. Kareev's (2000) analysis, including that it neglects that the adaptive value is not determined by the hit rate but by the posterior probability of hit and that only signal trials are considered. The authors' analysis demonstrates that when these limitations are corrected for, the alleged benefit for small samples does not occur, and larger samples imply considerable improvement in the detection of correlations.     

Models provide specificity: Testing a proposed mechanism of visual working memory capacity development

Numerous studies have established that visual working memory has a limited capacity that increases during childhood. However, debate continues over the source of capacity limits and its developmental increase. Simmering (2008) adapted a computational model of spatial cognitive development, the Dynamic Field Theory, to explain not only the source of capacity limitations but also the developmental mechanism. Capacity is limited by the balance between excitation and inhibition that maintains multiple neural representations simultaneously in the model. Development occurs according to the Spatial Precision Hypothesis, which proposes that excitatory and inhibitory connections strengthen throughout early childhood. These changes in connectivity result in increasing precision and stability of neural representations over development. Here we test this developmental mechanism by probing children's memory in a single-item change detection task. Results confirmed the model's predictions, providing further support for this account of visual working memory capacity development.     

Canonical correlation and chi-square: relationships and interpretation

A 2 x 2 chi-square can be computed from a phi coefficient, which is the Pearson correlation between two binomial variables. Similarly, chi-square for larger contingency tables can be computed from canonical correlation coefficients. The authors address the following series of issues involving this relationship: (a) how to represent a contingency table in terms of a correlation matrix involving r - 1 row and c - 1 column dummy predictors; (b) how to compute chi-square from canonical correlations solved from this matrix; (c) how to compute loadings for the omitted row and column variables; and (d) the possible interpretive advantage of describing canonical relationships that comprise chi-square, together with some examples. The proposed procedures integrate chi-square analysis of contingency tables with general correlational theory and serve as an introduction to some recent methods of analysis more widely known by sociologists.     

Canonical Correlation and Chi-Square: Relationships and Interpretation

A 2 × 2 chi-square can be computed from a phi coefficient, which is the Pearson correlation between two binomial variables. Similarly, chi-square for larger contingency tables can be computed from canonical correlation coefficients. The authors address the following series of issues involving this relationship: (a) how to represent a contingency table in terms of a correlation matrix involving r - 1 row and c - 1 column dummy predictors; (b) how to compute chi-square from canonical correlations solved from this matrix; (c) how to compute loadings for the omitted row and column variables; and (d) the possible interpretive advantage of describing canonical relationships that comprise chi-square, together with some examples. The proposed procedures integrate chi-square analysis of contingency tables with general correlational theory and serve as an introduction to some recent methods of analysis more widely known by sociologists.     

Validating a measure of children's monitoring-blunting coping styles in dental situations

The monitoring-blunting theory of coping suggests that when faced with a threatening situation, individuals can respond by either monitoring or avoiding (blunting) threatening information. The current study sought to validate a scale of children's preferences for monitoring or blunting in dental situations (the Monitoring Blunting Dental Scale or MBDS). The psychometric characteristics of the scale were assessed in a sample of 240 New Zealand children aged 11-13. Reliability was adequate for both monitoring (α = 0.74) and blunting (α = 0.76) subscale scores. Convergent validity was indicated by strong correlations (>0.6) between the measure's subscales and those of a related scale, although discriminant validity with respect to dental anxiety was problematic for the blunting subscale. Exploratory factor analysis supported a two-factor monitoring-blunting model, although confirmatory factor analysis indicated reasonable but imperfect fit for this model, SBχ2(251) = 510.7, p < 0.001, RMSEA = 0.066. We reflect on conceptual issues which may underlie the difficulties experienced here and elsewhere in developing psychometrically sound measures of Miller's blunting construct and suggest that the monitoring subscale of the study scale may be most useful to other researchers.     

Evoked and event-related potentials in disorders of consciousness: A quantitative review

Sixty-one publications about evoked and event-related potentials (EP and ERP, respectively) in patients with severe Disorders of Consciousness (DoC) were found and analyzed from a quantitative point of view. Most studies are strongly underpowered, resulting in very broad confidence intervals (CI). Results of such studies cannot be correctly interpreted, because, for example, CI > 1 (in terms of Cohen’s d) indicate that the real effect may be very strong, very weak, or even opposite to the reported effect. Furthermore, strong negative correlations were obtained between sample size and effect size, indicating a possible publication bias. These correlations characterized not only the total data set, but also each thematically selected subset. The minimal criteria of a strong study to EP/ERP in DoC are proposed: at least 25 patients in each patient group; as reliable diagnosis as possible; the complete report of all methodological details and all details of results (including negative results); and the use of appropriate methods of data analysis. Only three of the detected 60 studies (5%) satisfy these criteria. The limitations of the current approach are also discussed.     

The Behavioural Inhibition Scale for Children Aged 3 to 6 (BIS 3-6): Validity Based on Its Relation with Observational Measures

The aim of this study is to explore the concurrent validity of the Behavioral Inhibition Scale 3-6 (BIS 3-6), a scale created for the early detection of the temperamental disposition toward social anxiety. Seventy-three participants were randomly selected from a wide sample of preschool-age children to undergo systematic observation using the Behavioral Inhibition Paradigm. Parents and teachers rated the BIS 3-6. Clinicians and researchers also measured behavioral inhibition. The BIS 3-6 scores correlate between r?=?0.2 and r?=?0.6 with the observational indicators, and all correlations are in the expected direction. A discriminant analysis supports a good capability of the BIS 3-6 scores to identify extreme inhibition. Consistent with previous research and given the discrepancy among parent and teacher reports and observational measures, the moderate convergence among the BIS 3-6 trait-measurements and the observational state-measurements support the validity of the BIS 3-6 scores. This study advances the validation process for a new tool intended to early detect impairing behavioral inhibition.     

When can categorical variables be treated as continuous? A comparison of robust continuous and categorical SEM estimation methods under suboptimal conditions

A simulation study compared the performance of robust normal theory maximum likelihood (ML) and robust categorical least squares (cat-LS) methodology for estimating confirmatory factor analysis models with ordinal variables. Data were generated from 2 models with 2-7 categories, 4 sample sizes, 2 latent distributions, and 5 patterns of category thresholds. Results revealed that factor loadings and robust standard errors were generally most accurately estimated using cat-LS, especially with fewer than 5 categories; however, factor correlations and model fit were assessed equally well with ML. Cat-LS was found to be more sensitive to sample size and to violations of the assumption of normality of the underlying continuous variables. Normal theory ML was found to be more sensitive to asymmetric category thresholds and was especially biased when estimating large factor loadings. Accordingly, we recommend cat-LS for data sets containing variables with fewer than 5 categories and ML when there are 5 or more categories, sample size is small, and category thresholds are approximately symmetric. With 6-7 categories, results were similar across methods for many conditions; in these cases, either method is acceptable. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

Is acculturation unidimensional or bidimensional? A head-to-head comparison in the prediction of personality, self-identity, and adjustment

The unidimensional model of acculturation posits that heritage and mainstream culture identifications have a strong inverse relation, whereas the bidimensional model posits that the 2 identifications are independent. The authors compared these models in 3 samples of ethnic Chinese (ns = 164, 150, and 204), 1 sample of non-Chinese East Asians (n = 70), and one diverse group of acculturating individuals (n = 140). Although the unidimensional measure showed a coherent pattern of external correlates, the bidimensional measure revealed independent dimensions corresponding to heritage and mainstream culture identification. These dimensions displayed patterns of noninverse correlations with personality, self-identity, and psychosocial adjustment. The authors conclude that the bidimensional model is a more valid and useful operationalization of acculturation.     

Signal-to-noise ratio sensitivity in ERPs to stimulus and task complexity: different effects for early and late components

Traditionally, early and late ERP components are evaluated by the latency and amplitude of their components. We investigated their signal-to-noise (S/N) ratio: how well individual ERP trials correlate with their overall averaged ERP. High correlations indicate minimal noise or individual trial variability while low correlations reflect greater trial variability. Continuous EEG activity was recorded from 57 university students during single- and dual-task conditions in a within-subjects paradigm (easy and difficult tone discrimination; with and without verbal working memory task). For early components, the addition of the second task increased the correlations between the individual trials and the averaged ERPs. For the late components, both the addition of the second task and an increase in stimulus difficulty decreased individual trial correlations. Results suggest that the S/N ratio analysis is a useful method for highlighting differences between early and late components associated with stimulus processing manipulations.     

Factor structure of the Eyberg Child Behavior Inventory: a parent rating scale of Oppositional Defiant Behavior Toward Adults, Inattentive Behavior, and Conduct Problem Behavior

Used the Eyberg Child Behavior Inventory (ECBI) to measure disruptive behavior problems in children and adolescents. A controversy exists, however, on the dimensional structure of the ECBI. To evaluate this issue, an exploratory factor analysis was first performed on a sample of 1,263 children and adolescents. This analysis identified 3 meaningful factors (i.e., Oppositional Defiant Behavior Toward Adults, Inattentive Behavior and Conduct Problem Behavior) and a fourth, poorly defined factor. A confirmatory factor analysis (CFA) evaluated the fit of the 3 meaningful factors in a second sample of 1,264 children and adolescents. The 3-factor model with 2 correlated errors provided a excellent fit. This 3-factor model also provided a significantly better fit than 2- and 1-factor models. Multiple group CFA indicated that the factor pattern, item-factor loadings, factor correlations, and correlated errors were equivalent across the samples. The CFA on sex yielded similar results. Initial normative information is presented for boys (n = 1,322) and girls (n = 1,205) within 4 age ranges (i.e., 2-5, 6-9, 10-13, 14-17) for the 3 factors. The use of these 3 factors, especially Oppositional Defiant Behavior and Conduct Problem Behavior, should make the ECBI more useful as a screening and outcome measure.     

Personality types and traits in the Vocational Preference Inventory

The relationships between the six scales on which Holland's (1973) theory is based (viz., Realistic, Investigative, Social, Conventional, Enterprising, Artistic) and the five other scales (viz., Self-control, Masculinity, Status, Infrequency, Acquiescence) of the Vocational Preference Inventory (VPI) (Holland, 1970) were investigated using canonical analysis. Considering the six personality type scales as one set of variables and the five trait scales of the VPI as the second set of variables, five significant canonical correlations were obtained for a sample of 373 mostly white undergraduate students. In a second study, three significant canonical correlations were found for a sample of 115 black college students at another school. The weights of the VPI scales suggested that three patterns of relationships among the scales are shared by the black sample and the mostly white sample.     

Healthy ageing,perceived motor‐efficacy,and performance on cognitively demanding action tasks

Current measures assessing older adults' functional ability detect existing limitations on essential tasks rather than changes in other aspects of functioning that could indicate future limitations. The perceived motor‐efficacy scale was developed to measure capability beliefs of healthy older adults across a range of daily action tasks. Subscales were developed through interviews with older volunteers and academics, then administered to participants aged 60–96 (N=300). Factor analysis of subscale scores produced 10 subscales. These demonstrated strong internal reliability, which was replicated with a second sample aged 60–92 (N=167). The influence of perceived motor‐efficacy on performance of cognitively demanding action tasks was investigated with a third sample aged 60–88 (N=134). On a task assessing the inhibition of an inappropriate action, older adults in their 80s with high confidence produced minor errors, whereas those with lower confidence produced extreme errors. On another task assessing the ability to inhibit a previously learnt action, those with high levels of perceived motor‐efficacy performed better amongst those least able to inhibit, but more poorly among those most able. Perceived motor‐efficacy may therefore be useful in identifying older adults at risk of functional limitations and enabling interventions before the onset of illness.     

The Development and Validation of the Multicomponent AIDS Phobia Scale

The development, reliability, and validity of a new instrument, the Multicomponent AIDS Phobia Scale (MAPS), is described. Based on a sample of 181 university students, the results indicate that the MAPS has strong internal consistency and moderate test-retest reliability. In addition, an assessment of concurrent and discriminant validity indicates statistically significant correlations with other self-report measures of anxiety, hypochondriasis, obsessive-compulsive disorder, and fear of AIDS. The results of a factor analysis indicate that the scale consists of two factors: Fear of Infection and Fear of Others/Avoidance. Although further research with the MAPS in a clinical population is warranted to investigate the generalizability of this study's results, the instrument appears to be a reliable and valid measure of AIDS Phobia and may prove useful for improving clinical assessment and documenting treatment outcome.     

Character Strengths: Stability and change from a military college education

A service academy military education seeks to develop character. Twenty-four character strengths measured by the Values in Action – Individual Strengths instrument are examined longitudinally to determine effects on character from a service academy education. Significant growth equations were obtained for Citizenship-Teamwork, Hope-Optimism, Fairness, Capacity to Love and be Loved, Appreciation of Beauty, Industry-Perseverance, Zest-Enthusiasm, Spirituality, Creativity, Leadership, Humor-Playfulness, Judgment, and Love of Learning from a mixed models analysis (overall Type 1 error set at .05). Based upon differences expected from a cross-sectional national sample it was inferred that the military college education differentially affected all character strengths except Gratitude, Citizenship-Teamwork, Creativity, Hope-Optimism, Capacity to Love and be Loved, Humor-Playfulness, Perspective, Modesty-Humility, Appreciation of Beauty, and Judgment.     

Rorschach interrater agreement estimates: An empirical evaluation

A standardized estimation of Rorschach interrater agreement is needed. Percentage agreement, although widely used, is found to be unsuitable. Forty-one protocols from adults in both a normal and a psychiatric sample were scored by two or three scorers, making 85 scoring pairs. Percentage agreement, correlations (phi and Pearson's r ), and kappa were computed on single response, total score, and category level. Percentage agreement shows minimal variation. Even when exceeding 0.80, it can obscure major disagreements. Kappa and correlations both vary in a similar way with level of disagreement. Total score level does not give additional information compared to single score and category levels. Kappa proved to be conservative and reliable and is therefore suggested as a standard estimate.     

Scale validation via quantifying item validity using the Dm index

While most validity indices are based on total test scores, this paper describes a method for quantifying the construct validity of items. The approach is based on the item selection technique originally described by Piazza in 1980. Unfortunately, Piazza's P2 index suffers from some substantial limitations. The Dm coefficient provides an alternative which can be used for item selection and provides a validity index for a set of items. The index is similar to that of traditional criterion-related validity indices. Criterion-related validity is used to demonstrate the accuracy of hypothesized relations of the measure with outcome variables of interest in research and practice. This method may be useful when the sample of items or persons is small, rendering more traditional approaches such as factor analysis or item response theory inappropriate. An example of how to use the technique is provided.     

Relationships between physical activity and motor skills in middle school children

The purpose of this study was to examine the relationships between physical activity measured as pedometer steps and performance on three motor skill tests. A secondary purpose was to determine if middle school children are meeting the recommendation for the number of daily steps. A sample (n =217) of 6th, 7th and 8th grade students participated. Each subject wore a Digi-Walker pedometer for three consecutive days. Subjects additionally recorded their pedometer steps in two 45 min.-physical education classes. There were strong significant correlations between daily steps taken by boys and girls, pedometer steps during physical education class and the AAHPERD Passing Test and the Bass Stick Balance. Similar correlations were weaker for the Side-Step Agility Test. Multivariate analysis of variance was utilized to examine variability of the three skills test by sex and year in school. Differences between students in Grades 7 and 8 on the AAHPERD Passing Test were significant. In addition, significant differences between daily pedometer steps and steps during physical education between Grades 6 and 7 were observed. Boys and girls had similar means on the AAHPERD Passing Test and Bass Stick Balance Test, but not on the Side-Step Agility Test. Scores on the three movement skills tested in this study were not strongly related to physical activity of the entire sample. Steps taken by middle school children appear not to be related to these measures of motor skills.     

THEORY TESTING: COMBINING PSYCHOMETRIC META-ANALYSIS AND STRUCTURAL EQUATIONS MODELING

This paper presents an overview of a useful approach for theory testing in the social sciences that combines the principles of psychometric meta-analysis and structural equations modeling. In this approach to theory testing, the estimated true score correlations between the constructs of interest are established through the application of meta-analysis (Hunter & Schmidt, 1990), and structural equations modeling is then applied to the matrix of estimated true score correlations. The potential advantages and limitations of this approach are presented. The approach enables researchers to test complex theories involving several constructs that cannot all be measured in a single study. Decision points are identified, the options available to a researcher are enumerated, and the potential problems as well as the prospects of each are discussed.     

Nonproportional sampling and the amplification of correlations

A theoretical analysis shows that sample correlations between two binary variables will be inflated when the frequency distributions of the two variables are flatter (i.e., closer to equal frequencies for the two values) in the sample than in the population. A correlation-assessment study in which participants were free to choose their own sample revealed an overwhelming preference for samples that included roughly the same number of observations for the two values of dichotomous variables, irrespective of their actual distribution in the population. Subjective estimates of observed correlations followed the sample correlations--which were inflated, as predicted--more closely than the true correlations. People's sampling behavior thus resembles that of a research designer who maximizes the chance of detecting a relationship, at the cost of diminished accuracy in estimating its strength.