Using Principal Components as Auxiliary Variables in Missing Data Estimation

To deal with missing data that arise due to participant nonresponse or attrition, methodologists have recommended an “inclusive” strategy where a large set of auxiliary variables are used to inform the missing data process. In practice, the set of possible auxiliary variables is often too large. We propose using principal components analysis (PCA) to reduce the number of possible auxiliary variables to a manageable number. A series of Monte Carlo simulations compared the performance of the inclusive strategy with eight auxiliary variables (inclusive approach) to the PCA strategy using just one principal component derived from the eight original variables (PCA approach). We examined the influence of four independent variables: magnitude of correlations, rate of missing data, missing data mechanism, and sample size on parameter bias, root mean squared error, and confidence interval coverage. Results indicate that the PCA approach results in unbiased parameter estimates and potentially more accuracy than the inclusive approach. We conclude that using the PCA strategy to reduce the number of auxiliary variables is an effective and practical way to reap the benefits of the inclusive strategy in the presence of many possible auxiliary variables.     

Perfectionism and athlete burnout in junior elite athletes: the mediating role of coping tendencies

Abstract

Recent research indicates that some dimensions of perfectionism are positively related to athlete burnout, whereas others are negatively related to athlete burnout. The divergent relationship between these dimensions of perfectionism and athlete burnout may be explained by different coping tendencies. The present investigation examined whether different coping tendencies mediate the relationship between self-oriented and socially prescribed perfectionism and burnout. Two-hundred and six junior elite athletes (M age=15.15 years, SD=1.88 years, range=11–22 years) completed measures of self-oriented and socially prescribed perfectionism, coping tendencies, and athlete burnout. Structural equation modeling indicated that the relationship between dimensions of perfectionism and athlete burnout was mediated by different coping tendencies. Higher levels of socially prescribed perfectionism was related to higher levels of avoidant coping which, in turn, was related to higher levels of athlete burnout. In contrast, higher levels of self-oriented perfectionism was related to higher levels of problem-focused coping and lower levels of avoidant coping which, in turn, was related to lower levels of athlete burnout. The findings suggest that different coping tendencies may underpin the divergent relationship between self-oriented and socially prescribed dimensions of perfectionism and athlete burnout.     

Kelly's Thought At Age 33: Suggestions For Conceptual And Methodological Refinements

Abstract

This paper argues that Neimeyer's (1985) crisis in methodology might not actually imply an overuse of grid techniques. Instead, the problem might consist of a serious underutilization of slightly different (but nonetheless constructivist) conceptual schemes and alternative methodologies derived from these conceptual schemes. In taking needed research risks we might hasten the next steps in the evolution of personal construct theory.     

The role of attention in subitizing: Is the magical number 1?

Subitizing, the fast and accurate enumeration of up to about 3 or 4 objects, has often been thought to be dependent on limited-capacity preattentive mechanisms. We used an attentional blink paradigm to investigate the extent to which subitizing requires attentional resources. On each trial, subjects identified a target letter in an RSVP stream and then enumerated dots presented in the stream that were either simultaneous with the target letter or followed it by up to 400 ms. For numerosities from 2 to 9, evidence of an attentional blink was observed; only enumeration of 0 or 1 elements was independent of lag. Thus, even enumeration of 2–3 objects, which is within the traditional subitizing range, appears to require attentional resources. The relation of this work to studies on the attentional requirements of detecting a unique item among distractors, a supposedly preattentive discrimination, is briefly discussed.     

Action-centred negative priming: Evidence for reactive inhibition

Experiments are described in which the spatial relationship between a stimulus and respondent is held constant in terms of visual and body-centred coordinates, while the complexity of the response is manipulated. It is demonstrated that the degree of complexity of an action directed to the same spatial location determines the level of negative priming observed. This result supports the notions that (1) inhibitory selection mechanisms act on action-centred representations, and (2) the level of inhibition is reactive to the relative potency of the evoked action. The results are also discussed in terms of alternative explanations of negative priming. It is concluded that the results are inconsistent with theories that do not involve inhibitory selection mechanisms.     

Top-down control settings and the attentional blink: Evidence for nonspatial contingent capture

Previous studies have shown that spatial attention can be “captured” by irrelevant events, but only if the eliciting stimulus matches top-down attentional control settings. Here we explore whether similar principles hold for nonspatial attentional selection. Subjects searched for a coloured target letter embedded in an RSVP stream of letters inside a box centred on fixation. On critical trials, a distractor, consisting of a brief change in the colour of the box, occurred at various temporal lags prior to the target. In Experiment 1, the distractor produced a decrement in target detection, but only when it matched the target colour. Experiments 2 and 3 provide evidence that this effect does not reflect masking or the dispersion of spatial attention. The results establish that (1) nonspatial selection is subject to “capture”, (2) such capture is contingent on top-down attentional control settings, and (3) control settings for nonspatial capture can vary in specificity.