Testing differences between nested covariance structure models: Power analysis and null hypotheses

For comparing nested covariance structure models, the standard procedure is the likelihood ratio test of the difference in fit, where the null hypothesis is that the models fit identically in the population. A procedure for determining statistical power of this test is presented where effect size is based on a specified difference in overall fit of the models. A modification of the standard null hypothesis of zero difference in fit is proposed allowing for testing an interval hypothesis that the difference in fit between models is small, rather than zero. These developments are combined yielding a procedure for estimating power of a test of a null hypothesis of small difference in fit versus an alternative hypothesis of larger difference.     

Personal goals and psychological growth: testing an intervention to enhance goal attainment and personality integration

We hypothesized that semester goal attainment provides a route to short-term psychological growth. In an attempt to enhance this process, we randomly assigned participants to either a goal-training program or to a control condition. Although there were no main effects of program participation on later goal attainment, important interactions were found. Consistent with a "prepared to benefit" model, participants already high in goal-based measures of personality integration perceived the program as most useful and benefited the most from the program in terms of goal attainment. As a result, they became even more integrated and also increased in their levels of psychosocial well-being and vitality. Implications for theories of short-term growth and positive change are discussed, as is the unanswered question of how to help less-integrated persons grow.     

The dimensions of stage theories

Stage theories are commonly used to represent the structure of cognitive processes in the domains of cognitive processing and cognitive development. Hierarchical unidimensional theories consisting of a single sequence of stages through which development proceeds in one direction only have predominated. However, a review of stage theories revealed that a two-dimensional, interactive (multidimensional) structure is warranted. Particularly in the area of cognitive development, results of research have supported subdivision of the stages of prominent unidimensional theories. Following this trend a small number of theorists have developed multidimensional theories, most of which consist of a sequence of stages in which each stage contains a number of subsidiary stages or levels. The emergence of a similar trend in other domains is examined, and the prospects of using an existing multidimensional framework to enable future comparisons and integration of different stage theories is explored.     

Sexuality and cyberporn: Towards a new agenda for research

This article presents theoretical considerations based on cultural analysis approaches to studying pornography and sexuality as a means of starting to suggest a new agenda for cyberporn research. By bringing to the forefront concepts of how subjectivity and sexuality are produced within the computer/Internet apparatus, I hope to diversify the focus in cyberporn research away from social science approaches and pre-Foucaultian assumptions of the subject which obscure understandings of new media and cyberporn use. Through a summary of visual culture studies and reception studies of pornography, I argue that cyberporn must be understood as contingent within the encoding and decoding processes and discourses of sexuality (Foucault) in which it is produced and consumed. My focus here is the home office/terminal as the site of reception/cyberporn use. While there is potential for a great variety of cultural analytic approaches to the study of cyberporn and how new media use influences sexuality, I end with specific suggestions for researching cyberporn reception in the home. The computer’s allure is more than utilitarian or aesthetic; it is erotic. Instead of a refreshing play with surfaces, as with toys or amusements, our affair with information machines announces a symbiotic relationship and ultimately a mental marriage to technology. Rightly perceived, the atmosphere of cyberspace carries the scent that once surrounded Wisdom. The world rendered as pure information not only fascinates our eyes and minds, but also captures our hearts. We feel augmented and empowered. Our hearts beat in the machines. This is Eros. (Michael Heim, The Metaphysics of Virtual Reality)     

The emotional attentional blink is robust to divided attention

The emotional attentional blink (EAB) refers to a temporary impairment in the ability to identify a target when it is preceded by an emotional distractor. It is thought to occur because the emotional salience of the distractor exogenously captures attention for a brief duration, rendering the target unattended and preventing it from reaching awareness. Here we tested the extent to which the EAB can be attenuated by inducing a diffuse top-down attentional state, which has been shown to improve target identification in an analogous attentional phenomenon, the attentional blink. Rapid sequences of landscape images were presented centrally, and participants reported the orientation of a ± 90° rotation of a landscape target. To induce a diffuse state of attention, participants were given a secondary task of monitoring for the appearance of a colored dot in the periphery. We found that emotional distractors impaired target recognition performance to comparable extents, regardless of whether or not participants concurrently performed the peripheral-monitoring task. Moreover, we found that performance of the secondary task led to an impaired ability to ignore neutral distractors. Subjective ratings of target vividness mirrored the behavioral accuracy, with frequent reports of intermediate levels of vividness suggesting that the EAB might impair target visibility in a graded manner. Our results demonstrate that the EAB is robust to manipulations of top-down attention, suggesting that the temporary capture of attention by emotionally salient stimuli involves processes that are distinct from those that produce the attentional blink.     

Calculating and graphing within-subject confidence intervals for ANOVA

The psychological and statistical literature contains several proposals for calculating and plotting confidence intervals (CIs) for within-subjects (repeated measures) ANOVA designs. A key distinction is between intervals supporting inference about patterns of means (and differences between pairs of means, in particular) and those supporting inferences about individual means. In this report, it is argued that CIs for the former are best accomplished by adapting intervals proposed by Cousineau (Tutorials in Quantitative Methods for Psychology, 1, 42–45, 2005) and Morey (Tutorials in Quantitative Methods for Psychology, 4, 61–64, 2008) so that nonoverlapping CIs for individual means correspond to a confidence for their difference that does not include zero. CIs for the latter can be accomplished by fitting a multilevel model. In situations in which both types of inference are of interest, the use of a two-tiered CI is recommended. Free, open-source, cross-platform software for such interval estimates and plots (and for some common alternatives) is provided in the form of R functions for one-way within-subjects and two-way mixed ANOVA designs. These functions provide an easy-to-use solution to the difficult problem of calculating and displaying within-subjects CIs.     

Optimal sample sizes for precise interval estimation of Welch’s procedure under various allocation and cost considerations

Welch’s (Biometrika 29: 350–362, 1938) procedure has emerged as a robust alternative to the Student’s t test for comparing the means of two normal populations with unknown and possibly unequal variances. To facilitate the advocated statistical practice of confidence intervals and further improve the potential applicability of Welch’s procedure, in the present article, we consider exact approaches to optimize sample size determinations for precise interval estimation of the difference between two means under various allocation and cost considerations. The desired precision of a confidence interval is assessed with respect to the control of expected half-width, and to the assurance probability of interval half-width within a designated value. Furthermore, the design schemes in terms of participant allocation and cost constraints include (a) giving the ratio of group sizes, (b) specifying one sample size, (c) attaining maximum precision performance for a fixed cost, and (d) meeting a specified precision level for the least cost. The proposed methods provide useful alternatives to the conventional sample size procedures. Also, the developed programs expand the degree of generality for the existing statistical software packages and can be accessed at brm.psychonomic-journals.org/content/ supplemental.