Secular Declines in Spearman's g: Some Evidence from the United States

The Flynn Effect (J. Flynn, 1987) refers to the apparent increases in intelligence quotient (IQ) observed over the past few decades. A related phenomenon is that the variance in test scores accounted for by Spearman's g (C. Spearman, 1904) varies according to IQ level. That is, g accounts for less variance in high IQ groups than in low IQ groups. Spearman termed this variant aspect of g the “law of diminishing returns.” This study extends prior research on the Flynn Effect and the law of diminishing returns by examining changes in the statistical importance of Spearman's g that may accompany secular increases in IQ. Based on the standardization data from the United States versions of the Wechsler scales (i.e., Wechsler Preschool and Primary Scales of Intelligence, D. Wechsler, 1967; Wechsler Intelligence Scale for Children, D. Wechsler, 1949; Wechsler Adult Intelligence Scale, D. Wechsler, 1955), this study indicated that, in most cases, the statistical significance of Spearman's g has indeed declined over the past several years. A. R. Jensen (1998) suggested that the components of the Flynn Effect warrant special investigation. The present study addresses this issue, in part by analyzing the Verbal and Performance subscales of the Wechsler scales. Additionally, this study further confirms the law of diminishing returns as applicable to different ages and time periods.     

An Admissible Semantics for Propositionally Quantified Relevant Logics

The Routley-Meyer relational semantics for relevant logics is extended to give a sound and complete model theory for many propositionally quantified relevant logics (and some non-relevant ones). This involves a restriction on which sets of worlds are admissible as propositions, and an interpretation of propositional quantification that makes ∀ pA true when there is some true admissible proposition that entails all p-instantiations of A. It is also shown that without the admissibility qualification many of the systems considered are semantically incomplete, including all those that are sub-logics of the quantified version of Anderson and Belnap’s system E of entailment, extended by the mingle axiom and the Ackermann constant t. The incompleteness proof involves an algebraic semantics based on atomless complete Boolean algebras.     

Bias versus bias: Harnessing hindsight to reveal paranormal belief change beyond demand characteristics

Psychological change is difficult to assess, in part because self-reported beliefs and attitudes may be biased or distorted. The present study probed belief change, in an educational context, by using the hindsight bias to counter another bias that generally plagues assessment of subjective change. Although research has indicated that skepticism courses reduce paranormal beliefs, those findings may reflect demand characteristics (biases toward desired, skeptical responses). Our hindsight-bias procedure circumvented demand by asking students, following semester-long skepticism (and control) courses, to recall their precourse levels of paranormal belief. People typically remember themselves as previously thinking, believing, and acting as they do now, so current skepticism should provoke false recollections of previous skepticism. Given true belief change, therefore, skepticism students should have remembered themselves as having been more skeptical than they were. They did, at least about paranormal topics that were covered most extensively in the course. Our findings thus show hindsight to be useful in evaluating cognitive change beyond demand characteristics.     

An R package to compute commonality coefficients in the multiple regression case: An introduction to the package and a practical example

Multiple regression is a widely used technique for data analysis in social and behavioral research. The complexity of interpreting such results increases when correlated predictor variables are involved. Commonality analysis provides a method of determining the variance accounted for by respective predictor variables and is especially useful in the presence of correlated predictors. However, computing commonality coefficients is laborious. To make commonality analysis accessible to more researchers, a program was developed to automate the calculation of unique and common elements in commonality analysis, using the statistical package R. The program is described, and a heuristic example using data from the Holzinger and Swineford (1939) study, readily available in the MBESS R package, is presented.     

A visual approach to statistical power analysis on the microcomputer

Computer programs for statistical power analysis typically require the user to provide a series of values and respond by reporting the corresponding power. These programs provide essentially the same functions as a published text, albeit in a more convenient form. In this paper, we describe a program that instead uses innovative graphic techniques to provide insight into the interaction among the factors that determine power. For example, fort tests, the means and standard deviations of the two distributions, sample sizes, and alpha are displayed as bar graphs. As the researcher modifies these values, the corresponding values of beta (also displayed as a bar graph) and power are updated and displayed immediately. By displaying all of the factors that are instrumental in determining power, the program ensures that each will be addressed By allowing the user to determine the impact that any modifications will have on power, the program encourages an appropriate balance between alpha and beta while working within the constraints imposed by a limited sample size. The program also allows the user to generate tables and graphs to document the impact of the various factors on power. In addition, the program enables the user to run on-screen Monte Carlo simulations to demonstrate the importance of adequate statistical power, and as such, it can serve as a unique educational tool.     

Verbal accounts and attributions of social motives

The effects of verbal accounts offered by a threatener on targets' subsequent attributions of the threatener's social motives was studied. Following a standardized interaction in a Prisoner's Dilemma game the subjects' opponent offered one of three accounts for using threats: cooperative intent, establishment of transrelational equity, or ignorance. In a fourth condition the confederate offered no account for his actions. Attributions were assessed by having subjects rate each of four responses representative of the social motives of cooperation, competition, apathy, and deceit in five different situations. It was found that the type of account had specific attributional effects. A cooperative account led to a correspondent inference of a cooperative disposition, a transrelational equity account was apparently perceived as illegitimate and led to an attribution of a deceitful motive, and an excuse of ignorance was linked with apathy.     

INSTRUCTIONS,FEEDBACK, PRAISE,BONUS PAYMENTS,AND TEACHER BEHAVIOR1

The study was conducted within a training and demonstration center for teachers from several different school districts. The teachers staffing the center were employees of the host school district who volunteered to serve in the center. Unfortunately, these volunteers did not always use the program materials appropriately and therefore did not always provide clear models for visiting teachers. In particular, four of the volunteer teachers did not always instruct their students from the appropriate reading text, even when encouraged to do so by the principal of the school in which the center was located. Various procedures were employed to alter this situation. The experimenter, (associate director of the training and demonstration center) provided instructions, feedback, and praise regarding use of the appropriate reading text. These procedures had clear effects with only one teacher. Then, merit or bonus payments were provided for teachers who used the appropriate reading text for criterion periods of time; a procedure that was very effective with all four teachers. The problem worked on in this study is typical of those faced by workers in public institutions where change cannot be brought about by the researcher's authority. All teachers in the present study had the necessary skills to demonstrate accurately the prescribed program procedures, but they did not always do so until the bonus payment was used. Although the bonus payment procedure might be inappropriate in some school situations, the procedure could easily be adjusted to accommodate the established practices of many schools. For example, establishment of explicit performance criterion and use of in-service stipends for meeting criterion performance during school hours, rather than attendance at meetings after school, might well be comparably effective.     

Signal/noise ratios for domain-referenced tests

Using the assumption of randomly parallel tests and concepts from generalizability theory, three signal/noise ratios for domain-referenced tests are developed, discussed, and compared. The three ratios have the same noise but different signals depending upon the kind of decision to be made as a result of measurement. It is also shown that these ratios incorporate a definition of noise or error which is different from the classical definition of noise typically used to characterize norm-referenced tests. Part of the work leading to this paper was accomplished while the authors were assistant professors at the State University of New York at Stony Brook.