The theoretical status of latent variables.

This article examines the theoretical status of latent variables as used in modern test theory models. First, it is argued that a consistent interpretation of such models requires a realist ontology for latent variables. Second, the relation between latent variables and their indicators is discussed. It is maintained that this relation can be interpreted as a causal one but that in measurement models for interindividual differences the relation does not apply to the level of the individual person. To substantiate intraindividual causal conclusions, one must explicitly represent individual level processes in the measurement model. Several research strategies that may be useful in this respect are discussed, and a typology of constructs is proposed on the basis of this analysis. The need to link individual processes to latent variable models for interindividual differences is emphasized. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Estimating the magnitude of experimental effects.

Discusses the increasing awareness that the mere statistical significance of an experimental effect is insufficient to warrant the conclusion that the effect is large and practically important. A number of related measures of the magnitude of experimental effects which can be applied to the results of a 1-way analysis of variance but not to the results of a more complicated design are available. The proper measure for a complex design depends on whether other factors are fixed or random, and the uncritical following of advice given in the literature can result in serious over- or underestimation of the magnitude of experimental effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Predicting group-level outcome variables from variables measured at the individual level: A latent variable multilevel model.

In multilevel modeling, one often distinguishes between macro-micro and micro-macro situations. In a macro-micro multilevel situation, a dependent variable measured at the lower level is predicted or explained by variables measured at that lower or a higher level. In a micro-macro multilevel situation, a dependent variable defined at the higher group level is predicted or explained on the basis of independent variables measured at the lower individual level. Up until now, multilevel methodology has mainly focused on macro-micro multilevel situations. In this article, a latent variable model is proposed for analyzing data from micro-macro situations. It is shown that regression analyses carried out at the aggregated level result in biased parameter estimates. A method that uses the best linear unbiased predictors of the group means is shown to yield unbiased estimates of the parameters. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Estimating interaction effects among overlapping pairs.

"This paper offers a method, given a collection of scores obtained by observing pairs of persons, of constructing scores in which the contributions of individuals are held constant so that the variability among the resulting 'interaction scores' may be attributed to the conditions specifying the obtained pair-scores and not to characteristics associated with the persons individually." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The interactive effects of conscientiousness and agreeableness on job performance.

The authors hypothesized that the relationship between conscientiousness and job performance would be stronger for persons high in agreeableness than for those low in agreeableness. Results of hierarchical moderated regression analyses for 7 independent samples of employees across diverse occupations provided support for the hypothesis in 5 of the samples. In samples supporting the hypothesis, among the highly conscientious workers, those low in agreeableness were found to receive lower ratings of job performance than workers high in agreeableness. One explanation for lack of an interaction between conscientiousness and agreeableness in the other 2 samples is that those jobs were not characterized by frequent, cooperative interactions with others. Overall, the results show that highly conscientious workers who lack interpersonal sensitivity may be ineffective, particularly in jobs requiring cooperative interchange with others. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The interactive effects of positive affect and conscientiousness on strain.

The purpose of our study was to more fully investigate a combination of personal resources, namely positive affect (PA) and conscientiousness, on emotional exhaustion, depersonalization, and job tension. We examined a sample of nurses employed by a metropolitan hospital and found that the combination of high positive affect and high levels of conscientiousness was associated with lower levels of all strain variables. Our findings suggested that conscientiousness strengthened the negative relationship between PA and job strain. Our results were consistent with the view that some dispositions can act as resources protecting individuals from experienced stress. Implications of these results, strengths and limitations, and directions for future research are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Additional exposures reverse the latent inhibitory effects of recent and remote exposures.

We studied the learning produced by simple exposures to a stimulus. Exposures depressed orienting and subsequent conditioned freezing in rats. A remotely preexposed conditioned stimulus (CS) conditioned better and overshadowed a novel CS more than a recently preexposed CS. Additional preexposures reversed these effects: a remotely preexposed CS elicited more orienting, conditioned worse and overshadowed less than a recently preexposed CS. Exposure to a compound composed of a novel CS and a remotely preexposed CS resulted in the novel CS subsequently conditioning better than a novel CS exposed in compound with a recently preexposed CS. The results were interpreted to mean that stimulus-alone exposures produce a loss in associability which recovers across time, that this restoration deepens the loss in associability, and that this deepening is regulated by a common error term. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The interactive effects of belongingness and charisma on helping and compliance.

This study tests the main and interactive effects of belongingness and perceived charismatic leadership on 2 forms of organizational citizenship behavior (helping and compliance). In line with expectations, a study of 115 manager-subordinate dyads demonstrates that employees show more helping (manager rated) when they have a stronger sense of belongingness at work and more helping as well as compliance when they perceive their leader to be more charismatic (subordinate rated). Belongingness partially mediates the relationship between charisma and helping. Also, as hypothesized, belongingness and charisma have interactive effects on employees' helping and compliance. The impact of perceived charisma on these behaviors is stronger for employees with a low sense of belongingness at work than for individuals with a higher sense of belongingness. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The effects of separate and interactive imagery on the recall of movement patterns.

Contrasted separate imagery instructions with interactive imagery instructions on memory for movement patterns. 48 undergraduates were presented pairs of movement patterns and were instructed to form separate images of each pattern or to form interactive images linking the patterns together. Cued recall performance and the organization of free recall was enhanced following interactive imagery instructions compared with separate imagery instructions. Total free recall, however, was similar for interactive and separate imagery. The advantage of interactive imagery over separate imagery in cued recall was attenuated when Ss were given instructions that imposed restrictions on the formation of their interactive images. Several explanations of the memorial consequences of imagery instructions are considered in light of these results, including I. Begg's (see record 1983-04913-001) organization-redintegration account of imagery instructions. (French abstract) (8 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ramsay-curve item response theory (RC-IRT) to detect and correct for nonnormal latent variables.

Popular methods for fitting unidimensional item response theory (IRT) models to data assume that the latent variable is normally distributed in the population of respondents, but this can be unreasonable for some variables. Ramsay-curve IRT (RC-IRT) was developed to detect and correct for this nonnormality. The primary aims of this article are to introduce RC-IRT less technically than it has been described elsewhere; to evaluate RC-IRT for ordinal data via simulation, including new approaches for model selection; and to illustrate RC-IRT with empirical examples. The empirical examples demonstrate the utility of RC-IRT for real data, and the simulation study indicates that when the latent distribution is skewed, RC-IRT results can be more accurate than those based on the normal model. Along with a plot of candidate curves, the Hannan-Quinn criterion is recommended for model selection. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The interactive effects of proactive personality and work-family interference on well-being.

Proactive personality was expected to moderate the relationship between controllable work and nonwork stressors (e.g., time-based work-family interference) and job/life satisfaction. Moderated multiple regression analyses of survey data from a sample of professionals (N=133) revealed a significant interaction between time-based family interfering-with work and proactive personality predicting life satisfaction and several main effects offering partial support for the hypothesized relationships (α     

Estimating the effects of toxicants on ecosystem services

Numerous functions of ecosystems are essential to the quality of human life, including the provision of food, the decomposition of sewage, the provision of portable water, and the replacement of breathable air. Although attributes of ecosystems directly of use to human societies are not the only ones worth protecting, emphasizing their services may be the most effective means of communicating risks of toxicants to the general public. However, although spatial and temporal scales of experiments to assess risk vary relatively little, actual spatial scales vary considerably, from local environments to global ecosystems. Generally, models are used to bridge these gaps in scale. In this paper, we examine ways in which toxicity test endpoints have been developed to describe effects of pollutants on essential ecosystem functions and the ways in which results are then extrapolated to scales that risk managers can use.     

REM drive and function: A study of the interactive effects of personality and presleep condition.

To investigate individual differences in REM sleep drive and function, a factorial design that manipulated type of experimental presleep stimulation (insolvable, solvable, or no problems), personality (repressor or sensitizer), and sleep manipulation (REM deprivation or nondeprivation) was used. Data were obtained from 169 18–28 yr old male undergraduates who completed the Neuroticism scale of the Maudsley Personality Inventory as a measure of repression–sensitization. REM drive was assessed in terms of initial REM sleep onset and inter-REM interval throughout the night; REM function was assessed in terms of postsleep mood (Multiple Affect Adjective Check List) and anagram performance. Results reveal REM drive to be an interactive function of personality and presleep stimulation, but there was little evidence of an adaptive function for REM sleep. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Preexposure effects in the spatial domain: Dissociation between latent inhibition and perceptual learning.

In 4 experiments, rats were given intermixed or blocked preexposure to an array of landmarks that subsequently defined the location of a hidden goal in a Morris pool task. Previous research has shown that intermixed preexposure to pairs of adjacent landmarks retards learning whereas preexposure to individual landmarks facilitates subsequent learning (J. Prados, V. D. Chamizo, & N. J. Mackintosh, 1999). Accordingly, in Experiment 1, intermixed and blocked preexposure to pairs of adjacent landmarks was found to retard learning. In Experiment 2, however, a scheduling effect was found: Rats given intermixed preexposure to the individual landmarks learned faster than rats given blocked or no preexposure. Experiment 3 showed that intermixed (but not blocked) preexposure to pairs of landmarks resulted in a facilitatory effect when preexposure and test were carried out in different contexts. Experiment 4 replicated within a single experiment the main results observed in Experiments 1 and 3. This pattern of results suggests that intermixed preexposure engages learning processes other than latent inhibition that facilitate subsequent learning of the navigation task. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Rumination, negative cognition, and their interactive effects on depressed mood.

Response styles theory posits that rumination represents a trait vulnerability to depression. Recent evidence has suggested that rumination predicts changes in depression more strongly among individuals with high levels of negative cognition. Three studies evaluated this model of interactive vulnerabilities. Study 1 provided empirical support for the distinction between rumination and negative cognitive content. The next 2 studies investigated the interactive model in the laboratory. Study 2 randomly assigned participants to either ruminate or distract following a sad mood induction. This study found that rumination was more strongly associated with dysphoria among individuals who report high levels of negative cognition. Similarly, Study 3 found that rumination and negative cognition interact to predict changes in dysphoria across a no-task delay period following a sad mood induction. These studies provide support for an interactive model in which rumination amplifies the deleterious effects of negative cognition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Additive and interactive effects on response time distributions in visual word recognition.

Across 3 different word recognition tasks, distributional analyses were used to examine the joint effects of stimulus quality and word frequency on underlying response time distributions. Consistent with the extant literature, stimulus quality and word frequency produced additive effects in lexical decision, not only in the means but also in the shape of the response time distributions, supporting an early normalization process that is separate from processes influenced by word frequency. In contrast, speeded pronunciation and semantic classification produced interactive influences of word frequency and stimulus quality, which is a fundamental prediction from interactive activation models of lexical processing. These findings suggest that stimulus normalization is specific to lexical decision and is driven by the task's emphasis on familiarity-based information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Understanding L.O.V.E. (left out variables error): A method for estimating the effects of omitted variables.

Whenever nonexperimental methods are used to test a hypothesis and 1 or more predictor (independent) variables that may affect the criterion (dependent) variable are omitted from the analyses, it is possible that the estimates of the effects of the predictors are biased or that the omitted variable could account entirely for the effects attributed to one or more of the predictors. In this article, a technique is developed for determining when a variable omitted from a linear model can account for the effects attributed to a predictor included in that model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Moderating effects of contextual variables on the relationship between hypnotic susceptibility and suggested analgesia.

Assessed 75 undergraduates high, medium, or low on hypnotic susceptibility (the Carleton University Responsiveness to Suggestion Scale) on the cold pressor task before and after 1 of 3 instructional treatments. The treatments were (a) brief instructions to try to reduce pain, (b) the same analgesia instructions preceded by a hypnotic induction procedure, and (c) no hypnotic induction or instructions. In the hypnotic treatment, susceptibility correlated significantly with reductions in reported pain, and high-susceptible Ss reported significantly larger pain reductions than did control Ss. In the instruction-alone treatment, there was no significant relationship between susceptibility and pain reduction, and Ss at all 3 susceptibility levels reduced reported pain significantly more than did controls and as much as did high-susceptible hypnotic Ss. Findings suggest that the correlation between hypnotic susceptibility and hypnotic analgesia is moderated by Ss' attitudes and expectancies concerning their own performance in situations defined as related to hypnosis. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential effects of contextual change on latent inhibition and on the habituation of an orienting response.

In Exp I, using 20 female hooded Lister rats, the habituation of the orienting response (OR) shown by Ss to a discrete visual stimulus (a 10-sec light) in a given training context (A) was monitored. Dishabituation occurred, in that the OR returned to its initial level, when the light was presented in a different and novel context (B). In Exp II, 24 female rats received 2 sessions/day, one in each of the 2 contexts. For experimental Ss, the light was presented in Context A until the OR habituated. In the test phase, the light was presented in Context B, but the OR was not restored, suggesting that the dishabituation seen in Exp I depended on the absolute novelty of Context B. In Exp III, Ss from Exp II were required to form a light–food association in both contexts. Slow learning was observed in Ss trained with the familiar light in Context A, but learning proceeded normally with the familiar light in Context B. Thus, a context change that failed to produce dishabituation was enough to prevent the occurrence of a latent inhibition effect. (35 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)