Connections between reading disability and behavior problems: Testing temporal and causal hypotheses

In this study of children's reading and behavior problem status from Grade 2 to Grade 4 of elementary school, we tested hypotheses concerned with the temporal and causal connections between these two closely associated disorders. Children with both, either, or neither kinds of problems were followed up over 2 years. While reading disability remained stable over time, there was greater variability in behavior problem status. Our data did not support the claim that reading problems lead to the development of behavior problems. Children who were comorbid had the worst outcome at follow-up, suggesting that behavior problems may exacerbate reading delay. Reading-disabled children were lower (albeit in the normal range) on intelligence, but when IQ was controlled, large group differences on reading and spelling were still evident. Attention deficit hyperactivity disorder (ADHD) type behavior problems significantly differentiated children with comorbid problems from children with behavior problems alone. Sex differences were noted in the association, with two-thirds of reading-disabled boys also having behavior problems and two-thirds of reading-disabled girls having no behavior problems, suggesting that pathways to reading disability may be gender specific.This research was supported by a grant from the Australian Research Council. Our thanks to the children, families and teachers for their support of our project.     

Evaluations of causal and conditional hypotheses

This study examined evaluations of causal and conditional hyptheses on the basis of individual exemplars. Subjects were presented scenes describing something that is malfunctioning and is taken to an expert. The expert makes a causal diagnosis and a prediction concerning an outcome following treatment. Four types of outcome evidence were provided: (1) treatment is provided and the problem is eliminated; (2) treatment is not provided and the problem is eliminated; (3) treatment is provided and the problem is not eliminated; and (4) treatment is not provided and the problem is not eliminated. Subjects were required to judge whether individual exemplars prove the diagnosis, disprove the diagnosis, or fail to test the diagnosis. A second form of problem presented the same scenes but required evaluation of the conditional prediction. A third form of problem did not present the causal scenes; the subject evaluated the conditional predication and no context. Three content domains were used: medical, mechanical, and arbitrary. There were three general results: (1) diagnoses were judged as less open to testing than predictive conditional hypotheses; (2) medical problems were judged differently from mechanical problems; and (3) problems lacking meaningful content or contexts led to more primitive response strategies.     

Processing speed, intelligence, creativity, and school performance: Testing of causal hypotheses using structural equation models

According to mental speed theory of intelligence, the speed of information processing constitutes an important basis for cognitive abilities. However, the question, how mental speed relates to real world criteria, like school, academic, or job performance, is still unanswered. The aim of the study is to test an indirect speed-factor model in comparison to rivaling models explaining the relationships between different mental abilities and performance. In this speed-factor model, basic cognitive processing is assumed to influence higher mental abilities (IQ and creativity). Intelligence and creativity themselves should be valid predictors of school performance. We computed bivariate correlations and structural equation models to test this hypothesis, using indicators of processing speed [Zahlen-Verbindungs-Test (ZVT) and Coding Test], psychometric intelligence [Kognitiver Fähigkeits-Test (KFT) and Raven's Advanced Progressive Matrices (APM)], creativity [Verbaler Kreativitäts-Test (VKT) and Verwendungs-Test (VWT)] and school performance (grades). In a sample of 271 students from German gymnasiums (Class Levels 9 to 11) the speed-factor model can reproduce at best the empirical relationships between processing speed, intelligence, creativity, and school performance: It assumes that processing speed influences higher mental abilities (intelligence and creativity), which, in the sequel, influence school performance. Therefore, processing speed seems to have no direct effect on school performance; the effect is indirect as it operates via mediation through higher cognitive abilities.     

Testing pattern hypotheses for covariance matrices

Maximum likelihood estimates of the free parameters, and an asymptotic likelihood-ratio test, are given for the hypothesis that one or more elements of a covariance matrix are zero, and/or that two or more of its elements are equal. The theory applies immediately to a transformation of the covariance matrix by a known nonsingular matrix. Estimation is by Newton's method, starting conveniently from a closed-form least-squares solution.Numerical illustrations include a test for equality of diagonal blocks of a covariance matrix, and estimation of quasi-simplex structures.     

Immediate and sustaining effects of extrinsic rewards on specific exploratory behavior

The purpose of the present investigation was to examine the immediate and sustaining effects of monetary and social rewards on specific exploratory behavior. Specific exploratory behavior was conceived as a behavioral expression of intrinsic motivation and was measured by the number of additional requests for viewing blurred tachistoscopically presented slides of varying degrees of uncertainty. The results of the study showed that when monetary and social rewards were presented contingent on performance, exploration increased at the upper levels of uncertainty above a control group. It was also found that after removal, females who had previously received social rewards sustained a significantly higher level of exploration above the control group, while males who had previously received social rewards, as well as both males and females who had previously received monetary rewards, did not differ significantly from the control. The discrepany between these findings and previous findings is explained in terms of theoretical differences in defining and measuring intrinsic motivation.     

Immediate attributional effects of success and failure in the field: Testing some laboratory hypotheses

Investigated how team success and failure are attributed to dispositional and situational factors as a function of immediate outcome of the group performance, past success of the team, and individual performance of team members within the group. 150 Little League baseball players' attributions for the team's outcome were taken separately with regard to team- and self-factors immediately after the conclusion of a game. The results reveal that success, independent of the margin of victory, is primarily assigned to effort and ability, while clear-loss is attributed to both effort and task difficulty. Conversely, bare-loss is seen to be mainly due to task difficulty and secondarily to low effort. The results are interpreted as supporting the notion of ego-centered causal judgments, but not necessarily the motive to enhance one's self, on the basis of the new proposition that effort has a different attributional meaning in the cases of success and failure; when losing effort is treated as an external factor, and when winning, effort tends to be interpreted as an internal factor. No differences with respect to attributions exist between individual players who perform poorly and those who excell within the team performance.     

Disagreement and causal learning: Others' hypotheses affect children's evaluations of evidence

When children evaluate evidence and make causal inferences, they are sensitive to the social context in which data are generated. This study investigated whether children learn more from evidence generated by an agent who agrees with them or from one who disagrees with them. Children in two age groups (5- and 6-year-olds and 9- and 10-year-olds) observed the functioning of a machine that lit up and played music in the presence of certain objects. After endorsing one of two plausible causal hypotheses, children observed a puppet either agree or disagree with their own hypotheses. The puppet then generated a further piece of evidence that confirmed, disconfirmed, or was neutral with respect to the children's hypotheses. When they were later asked to make causal inferences about objects they did not directly observe, children in both age groups responded differentially to identical evidence depending on whether the agent agreed or disagreed, and they often drew stronger inferences in response to disagreement. In addition, older children were particularly sensitive to disagreement when the evidence was ambiguous. Our results suggest that children consider the relationship between their own and others' hypotheses when evaluating evidence that others generate. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

Testing hypotheses involving Cronbach's alpha using marginal models

We discuss the statistical testing of three relevant hypotheses involving Cronbach's alpha: one where alpha equals a particular criterion; a second testing the equality of two alpha coefficients for independent samples; and a third testing the equality of two alpha coefficients for dependent samples. For each of these hypotheses, various statistical tests have been proposed. Over the years, these tests have depended on progressively fewer assumptions. We propose a new approach to testing the three hypotheses that relies on even fewer assumptions, is especially suited for discrete item scores, and can be applied easily to tests containing large numbers of items. The new approach uses marginal modelling. We compared the Type I error rate and the power of the marginal modelling approach to several of the available tests in a simulation study using realistic conditions. We found that the marginal modelling approach had the most accurate Type I error rates, whereas the power was similar across the statistical tests.     

Person-organization fit: Testing socialization and attraction-selection-attrition hypotheses

Using the socialization and attraction-selection-attrition (ASA) frameworks, this study examined the relation between employees’ work values and their organization’s values (person-organization fit). With a two year time interval, 140 respondents participated in a longitudinal study. After entry, socialization served to enhance homogeneity. The work values underwent small changes and the perception of fit with the organization grew. Despite high retention rates results confirmed the attrition effect. Results indicated that the lower the perceived match between own and organizational values at entry, the more likely it was that someone left the organization over time. We concluded that socialization as well as attrition mechanisms were present at the same time.     

Time and order effects on causal learning

Five experiments were conducted to explore trial order and retention interval effects upon causal predictive judgments. Experiment 1 found that participants show a strong effect of trial order when a stimulus was sequentially paired with two different outcomes compared to a condition where both outcomes were presented intermixed. Experiment 2 found that a 48-h retention interval eliminates the trial order effect, so that participants gave a global judgment about the relationship between the stimulus and the two outcomes equivalent to the one given by participants that received the two phases intermixed. This result was replicated in Experiment 3 in a situation in which the probability of the outcome in the presence of the cue was changed from .5 for both outcomes (Experiments 1, 2, 4, and 5) to .75 and .25 for outcomes 1 and 2, respectively. Experiment 4 found that retention intervals ranging from 45 min to 48 h eliminated the trial order effect similarly. Experiment 5 found that a 10-min retention interval replicated the effect of time upon sequential training found in precedent experiments, regardless of whether participants remained within the laboratory during the retention interval or spent it outside. The combined results of this experimental series suggest that retention intervals reduce retroactive interference in causal learning by allowing participants to use all the information presented across phases, rather than differentially increasing or decreasing retrieval of information about each of them.     

Two metamodels of causal effects

Two metamodels, termed Model S and Model V, are proposed for definition, measurement, and generalization of quantitative causal effects. The effect is defined as a part change in score in Model S and as a part change in variance in Model V. Two additional changes, total and remainder change, are defined. The latter is due to all other factors or variables than the cause, while total change is the sum of remainder and effect change. Furthermore, it is shown how contrafactual concepts, which imply that some parts of the study situation are supposed to be otherwise, enter into the metamodels. Casual effects are defined and measured in terms of non-contrafactual concepts, except that statistical induction includes contrafactual as well as non-contrafactual inferences. Non-statistical generalization involves both kinds of inferences. Contrafactual definitions are considered inadequate, and a contrafactual interpretation of statistical adjustment is unnecessary and should be replaced by a non-contrafactual one.     

Dopamine and serotonin systems modify environmental effects on human behavior: A review

The relative influences of genetic and environmental factors in the development of human behavior have been a long‐term topic for an intense debate. Recent behavioral genetic studies suggest focusing on the joint effect of genes and environment, and especially on the life‐course developmental interplay between nature and nurture. Vulnerability to environmental adversities and sensitivity to its benefits may be conditional on genetic background, and regarding psychological outcomes, these kinds of gene × environment interactions may be of higher importance than direct gene–trait associations. In our recent series of studies, we have shown that different variants of serotonergic and dopaminergic genes may moderate the influence of environmental conditions on a range of psychological outcomes, i.e. temperament, depression, hostility, and educational attainment. These studies suggest that depending on their genotype, people may be differentially sensitive to the environmental conditions they encounter. In the light of these results it seems highly plausible that the effects of genes may become evident only when studied in the context of environmental factors.     

Induced processing biases have causal effects on anxiety

After briefly describing the nature of emotional processing biases associated with vulnerability to anxiety, and a model of how they may be produced, we review new data on the experimental induction of attentional and interpretative biases. We show that these biases can be readily induced in the laboratory, in the absence of mood changes. However, induced biases exert effects on the processing of new information and cause congruent changes in state anxiety when they influence how emotionally significant information is encoded. We can therefore conclude that biases have causal effects on vulnerability to anxiety via their influence on how significant events are processed. Finally, we discuss how our model might account for the acquisition of processing bias and for when they can influence anxiety.     

Testing linear hypotheses illustrated by a simple example in correlation

The development of a criterion suitable for testing the significance of a correlation or regression coefficient is used as an illustration of the manner in which a research problem is bound to the selection of the particular data appropriate to collect and a fitting type of statistical analysis of the latter. The translation of the original inquiry into a problem of testing linear hypotheses is the means by which these two aspects of an investigation are held together. This presentation is offered as a plan which might be useful for some research workers in determining appropriate criteria for testing their particular hypotheses.     

Pavlovian conditioned stimulus effects upon instrumental choice behavior are reinforcer specific

In a transfer-of-control experiment with rats, Pavlovian CSs were tested for the specificity of their effects. The instrumental behavior consisted of a discriminative, conditional two-lever choice task in which qualitatively different appetitive reinforcers were contingent upon the two correct choices. In a Pavlovian phase, subjects experienced conditioning to establish either a CS⁺ or CS^? for one reinforcer or a CS⁺ or CS^? for the other reinforcer. Finally, in a test, these CSs were presented when there was the opportunity to make choice responses. The CS⁺s evoked choices of the lever which had eventuated in the reinforcer that had served as the Pavlovian US, while the CS^?s showed only a slight tendency to evoke the other choice responses. When the CSs were compounded with the original S^Ds, the CS⁺s had little effect upon the vigor of responding while the CS^?s reduced the vigor of responding to the S^D for the reinforcer that was the same as the US used in establishing the CS^?. The results are discussed in terms of associative mediational theory and the reinforcer specificity of Pavlovian conditioned excitation and inhibition.     

Testing clinical hypotheses by means of "falsificationist epistemology"

A family therapist using the "falsificationist epistemology" can, during the first session, test the hypotheses formulated on the telephone intake chart and also gather further information to reexamine and redefine these hypotheses. We shall examine a case treated by Dr. G. Prata, analyzing the most important phases of the first session, and stressing what methodological and tactical choices were designed to test the leading hypothesis of the "game" played by this family.