The Yale-Brown Obsessive-Compulsive Scale: Confirmatory Factor Analytic Findings

The psychometric properties of the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) have recently been heavily examined. Specifically, a number of researchers have been interested in determining the factor structure of this scale to find whether it best forms a one, two, or three factor model. The present study continued this examination by considering different scaling models using confirmatory factor analysis with a sample of individuals diagnosed with Obsessive-Compulsive Disorder (OCD). One hundred and forty-six individuals diagnosed with OCD participated and were administered the Y-BOCS and scales measuring depression (Hamilton Depression Rating Scale) and anxiety (Hamilton Anxiety Rating Scale). It was found that the Y-BOCS forms two different two-factor models. One model consisted of an obsessions and compulsions factor; the other composed of disturbance and symptom severity factors. It was likewise found that depression and anxiety were related to both factors in one model (disturbance and symptom severity). The finding that depression was related to obsessions and anxiety to compulsions was found, as in a previous factor analysis of the Y-BOCS. These findings suggest that OCD may be best characterized as a multidimensional syndrome that may not be adequately examined by a single unitary factor as described in the Y-BOCS.     

Temporal summation at the warmth threshold

Threshold levels for warmth aroused by infrared irradiation were measured in sLx Ss at durations between 0.05 and 10 sec. Beyond a critical duration of about a second, the threshold does not depend on duration. Below critical duration time t trades for irradiance ? by the formula ? = kt^?0.82. That these properties do not depend much on areal extent of stimulation was demonstrated by a study that compared temporal summation for two different areas of the same S’s skin. Individual differences in apparent absolute sensitivity were explored under the rubric of the theory of signal detection.     

On the form of learning curves

In a wide variety of learning experiments, cumulated measures of performance turn out to be a power function of practice time or number trials, typically with an exponent between 1 and 2. The effects of various conditions on the course of learning can frequently be described in terms of the two constants of the function.     

Statistical Learning Is Not Affected by a Prior Bout of Physical Exercise

This study examined the effect of a prior bout of exercise on implicit cognition. Specifically, we examined whether a prior bout of moderate intensity exercise affected performance on a statistical learning task in healthy adults. A total of 42 participants were allocated to one of three conditions—a control group, a group that exercised for 15 min prior to the statistical learning task, and a group that exercised for 30 min prior to the statistical learning task. The participants in the exercise groups cycled at 60% of their respective O₂max. Each group demonstrated significant statistical learning, with similar levels of learning among the three groups. Contrary to previous research that has shown that a prior bout of exercise can affect performance on explicit cognitive tasks, the results of the current study suggest that the physiological stress induced by moderate‐intensity exercise does not affect implicit cognition as measured by statistical learning.     

A pilot study of women’s affective responses to common and uncommon forms of aerobic exercise

Objective: To test the extent to which participants exposed to an uncommon versus common exercise stimulus would result in more favourable affect at post-task.

Design: Experimental design. Participants (N = 120), American women aged 18–45 years, were randomly assigned to complete 30-min of either the uncommon (HOOP; n = 58) or common (WALK; n = 62) exercise stimulus.

Main outcome measures: Self-reported affect and intentions for future exercise were measured before and after the 30-min exercise bout.

Results: Analyses of covariance were run to compare post-task affect across the HOOP and WALK conditions. At post-task, participants assigned to HOOP reported more positively valenced affect, higher ratings of positive activated affect, lower ratings of negative deactivated affect, and stronger intentions for future aerobic exercise compared to participants assigned to WALK.

Conclusions: Participants who completed an uncommon bout of aerobic exercise (HOOP) reported more favourable affect post-exercise, as well as stronger intentions for future exercise, compared to participants who completed a common bout of aerobic exercise (WALK). Future work using a longitudinal design is needed to understand the relationships between familiarity with an exercise stimulus, affective responses to exercise, motivation for future exercise behaviour and exercise maintenance over time.     

Using multidimensional item response theory to evaluate how response styles impact measurement

Multidimensional item response theory (MIRT) models for response style (e.g., Bolt, Lu, & Kim, 2014, Psychological Methods, 19, 528; Falk & Cai, 2016, Psychological Methods, 21, 328) provide flexibility in accommodating various response styles, but often present difficulty in isolating the effects of response style(s) from the intended substantive trait(s). In the presence of such measurement limitations, we consider several ways in which MIRT models are nevertheless useful in lending insight into how response styles may interfere with measurement for a given test instrument. Such a study can also inform whether alternative design considerations (e.g., anchoring vignettes, self-report items of heterogeneous content) that seek to control for response style effects may be helpful. We illustrate several aspects of an MIRT approach using real and simulated analyses.