A model is presented that demonstrates that a random response to external constraint can produce results similar to those predicted by more complex models. Behavior that appears rational, optimal, or adaptive may truly be a random response to external constraint. Predictions based on this model may provide appropriate null hypotheses. (SLD)

Three articles in this special issue explore issues related to the use and misuse of statistical significance testing, the major methodological issue in current educational research. Comments on these articles and rejoinders by the authors of the first three articles explore additional aspects of statistical significance testing. (SLD)

Although statistical significance testing as the sole basis for result interpretation is a flawed practice, significance tests can be useful as one of three criteria that must be demonstrated to establish a position empirically. Statistical significance testing provides evidence that an event did not happen by chance but gives no evidence of the…

Expresses a "middle-of-the-road" position on statistical significance testing, suggesting that it has its place but that confidence intervals are generally more useful. Identifies 10 errors of omission or commission in the papers reviewed that weaken the positions taken in their discussions. (SLD)

Presents two class activities for use with hypothesis testing in which students collect data to test for a difference in the mean number of chocolate chips per cookie between two brands. (Author/ASK)

The present case continues the series of anomia treatment studies with contextual priming (CP), being the second in-depth treatment study conducted for an individual suffering from semantically based anomia. Our aim was to acquire further evidence of the facilitation and interference effects of the CP treatment on semantic anomia. Based on the…

Offering perspectives in the teaching of statistics assists students, immersed in the study of detail, to see the leading principles of the subject more clearly. Especially helpful can be a perspective on the logic of statistical inductive reasoning. Such a perspective can bring to prominence a broad principle on which both interval estimation and…

Hornworms are good assay organisms for leaf toxins, and can be raised on an artificial medium ("chow"), consisting of corn meal, soy flour, dry milk, yeast and other additives and preservatives. The hornworm assay is less useful in ecological and toxicological research, but is very useful in learning about experimental design and hypothesis…

A Monte Carlo study extended the research of MacKinnon, Lockwood, Hoffman, West, and Sheets (2002) for single-level designs by examining the statistical performance of four methods to test for mediation in a multilevel experimental design. The design studied was a two-group experiment that was replicated across several sites, included a single…

Blanton and Jaccard questioned the 4-test regression method used by Greenwald et al. to test a pure multiplicative theory. The present authors address Blanton and Jaccard's concerns with a combination of simulations and meta-analysis. Simulations show that (a) Blanton and Jaccard's preferred simultaneous regression method has a severe power loss…

Does the modality of instructional messages affect learning? How does it affect different media? In this paper, I offer an answer to these questions by first proposing a theoretical framework from which effective instructional methods can be derived. Then, I report a set of studies where one method, the modality principle, was tested across…

Although most discussions today start from the assumption that the secular rise in IQ must be environmental in origin, three reasons warrant giving the genetic phenomenon heterosis a closer look as a potential cause. First, it easily accounts for both the high heritability and low shared environmental effects seen in IQ, findings that are…

Category-based inference is crucial for using past experiences to make sense of new ones. One challenge to inference of this kind is that most entities in the world belong to multiple categories (e.g., a jogger, a professor, and a vegetarian). We tested the hypothesis that the "degree of coherence" of a category-the degree to which category…

This study investigated whether and how visual representations of individual objects are bound in memory to scene context. Participants viewed a series of naturalistic scenes, and memory for the visual form of a target object in each scene was examined in a 2-alternative forced-choice test, with the distractor object either a different object…

This article provides an overview of the history of research on adolescence. In our view, the history of the scientific study of adolescence has had two overlapping phases and is now on the cusp of a third. The first phase, which began early in the 20th century and lasted about 70 years, was characterized by grand theoretical models that…