The use of latent trajectory models in psychopathology research

Despite the recent surge in the development of powerful modeling strategies to test questions about individual differences in stability and change over time, these methods are not currently widely used in psychopathology research. In an attempt to further the dissemination of these new methods, the authors present a pedagogical introduction to the structural equation modeling based latent trajectory model, or LTM. They review several different types of LTMs, discuss matching an optimal LTM to a given question of interest, and highlight several issues that might be particularly salient for research in psychopathology. The authors augment each section with a review of published applications of these methods in psychopathology-related research to demonstrate the implementation and interpretation of LTMs in practice.     

Experimental tests of an attitudinal theory of the gender gap in voting

This research examined the hypothesis that gender gaps in voting stem from differences in the extent to which men and women agree with candidates' issue stances. Two initial experiments portraying candidates by their sex and attitudes and a third experiment that also included information about political party produced the predicted attitudinal gender-congeniality effect: Participants of each sex reported greater likelihood, compared with participants of the other sex, of voting for the candidate who endorsed positions typically favored more by their own sex than the other sex. In addition, this gender-congeniality effect was present among Republican and independent participants but absent among Democratic participants because Democratic men as well as women favored candidates who advocated the positions typically favored by women. Interpretation invoked the importance of group interest based on gender as an influence on women's voting.     

Uncertainty in pigeons

Pigeons classified a display of illuminated pixels on a touchscreen as sparse or dense. Correct responses were reinforced with six food pellets; incorrect responses were unreinforced. On some trials an uncertain response option was available. Pecking it was always reinforced with an intermediate number of pellets. Like monkeys and people in related experiments, the birds chose the uncertain response most often when the stimulus presented was difficult to classify correctly, but in other respects their behavior was not functionally similar to human behavior based on conscious uncertainty or to the behavior of monkeys in comparable experiments. Our data were well described by a signal detection model that assumed that the birds were maximizing perceived reward in a consistent way across all the experimental conditions.     

Computerizing reading training: Evaluation of a latent semantic analysis space for science text

The effectiveness of a domain-specific latent semantic analysis (LSA) in assessing reading strategies was examined. Students were given self-explanation reading training (SERT) and asked to think aloud after each sentence in a science text. Novice and expert human raters and two LSA spaces (general reading, science) rated the similarity of each think-aloud protocol to benchmarks representing three different reading strategies (minimal, local, and global). The science LSA space correlated highly with human judgments, and more highly than did the general reading space. Also, cosines from the science LSA spaces can distinguish between different levels of semantic similarity, but may have trouble in distinguishing local processing protocols. Thus, a domain-specific LSA space is advantageous regardless of the size of the space. The results are discussedin the context of applying the science LSA to a computer-based version of SERT that gives online feedback based on LSA cosines.     

Estimating the mean effect size in meta-analysis: Bias,precision, and mean squared error of different weighting methods

Although use of the standardized mean difference in meta-analysis is appealing for several reasons, there are some drawbacks. In this article, we focus on the following problem: that a precision-weighted mean of the observed effect sizes results in a biased estimate of the mean standardized mean difference. This bias is due to the fact that the weight given to an observed effect size depends on this observed effect size. In order to eliminate the bias, Hedges and Olkin (1985) proposed using the mean effect size estimate to calculate the weights. In the article, we propose a third alternative for calculating the weights: using empirical Bayes estimates of the effect sizes. In a simulation study, these three approaches are compared. The mean squared error (MSE) is used as the criterion by which to evaluate the resulting estimates of the mean effect size. For a meta-analytic dataset with a small number of studies, theMSE is usually smallest when the ordinary procedure is used, whereas for a moderate or large number of studies, the procedures yielding the best results are the empirical Bayes procedure and the procedure of Hedges and Olkin, respectively.     

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Effects of response type on coordinated responses during arm movement

This paper reports some experimental results on the coordination of finger and vocal responses with passing through a target position in multjjoint arm movement. In Experiment 1, we found that the difference in the timing of finger and vocal responses cannot be attributed entirely to efferent or representational effects. Instead, it appears to reflect the extent to which information about the internal stimuli generated by the arm movement are available to the centers controlling these different responses. That is, it is a compatibility effect. In Experiment 2, the case in which a finger response is made on the same side of the body as the moving arm was compared with the case in which it is made with the contralateral hand, which remains static. The interaction effect observed suggests that the path-ways subserving coordinated responses are informationally encapsulated, so that information about arm movement is not shared between the neural centers controlling different coordinated responses.     

Recognizing Unfamiliar Faces: The Effects of Distinctiveness and View

Three experiments are reported in which the effects of viewpoint on the recognition of distinctive and typical faces were explored. Specifically, we investigated whether generalization across views would be better for distinctive faces than for typical faces. In Experiment 1 the time to match different views of the same typical faces and the same distinctive faces was dependent on the difference between the views shown. In contrast, the accuracy and latency of correct responses on trials in which two different faces were presented were independent of viewpoint if the faces were distinctive but were view-dependent if the faces were typical. In Experiment 2 we tested participants'recognition memory for unfamiliar faces that had been studied at a single three-quarter view. Participants were presented with all face views during test. Finally, in Experiment 3, participants were tested on their recognition of unfamiliar faces that had been studied at all views. In both Experiments 2 and 3 we found an effect of distinctiveness and viewpoint but no interaction between these factors. The results are discussed in terms of a model of face representation based on inter-item similarity in which the representations are view specific.