Development of key-pecking, pause, and ambulation during extended exposure to a fixed-interval schedule of reinforcement

Six pigeons key-pecked under a fixed-interval (FI) 3-min schedule of food presentation. Each pigeon was studied for 200 daily sessions with 15 intervals per session (3,000 total food presentations). Analyses included the examination of latency to first peck (pause), mean rate of key pecking, and ambulation. Characterizations of stable performance were assessed across measures of behavior and evaluated using commonly employed stability criteria. Stability of response rate and pause was identified better by assessments that evaluated variability and trend, rather than just variability. Between-subject differences in rate of acquisition and terminal values of steady-state performance of pause were observed, and stable pause durations took longer to develop than did stable key-pecking rates. Relative variability in response rate and pause duration decreased as the means increased. A temporally organized pattern of key-pecking (the so-called FI scallop) developed within 50 sessions of exposure to the schedule. Overall ambulation decreased during the early sessions of exposure and further analyses showed greater rates of ambulation during the pause than after it for 4 of the 6 pigeons. Performance under the FI 3-min schedule developed relatively slowly, and key-pecking, pause, and ambulation developed at different rates.     

Predicting counterproductive work behavior from the interaction of personality traits

Much attention has been given to enhancing the prediction of counterproductive work behavior (CWB), with a particular focus on the relationship between the five factor model of personality and CWB. Several scholars have advocated for a more complex view of this relationship, and rather than focusing simply on main effects, to examine the interaction of personality traits in predicting employee behavior. In consideration of the traits most strongly related to CWB, we examined the interaction between: (1) conscientiousness and emotional stability, (2) agreeableness and emotional stability, and (3) conscientiousness and agreeableness on CWB directed at individuals (CWB-I) and the organization (CWB-O). Results from a multi-national sample illustrate the interaction of traits increases the prediction of CWB over and above a single trait approach. The interactions suggest employees perform the least CWB when they are high on both traits (in the respective trait pairings), but low levels on either trait relate to increased CWB, and at levels comparable to individuals low on both traits. We conclude research on personality and CWB would benefit from an interactive approach as it allows for greater prediction of CWB-O and CWB-I, which is important in light of the organizational and interpersonal consequences of employee misbehavior.     

不稳定控制感剥夺损害工作记忆刷新功能

控制感剥夺会阻碍工作记忆中的转换功能,但对工作记忆中刷新功能的影响机制尚不清楚。据此,本文通过两个实验来探究控制感剥夺对工作记忆刷新功能的影响。结果发现,相较于基线水平,无论是通过行为无助任务（实验1）还是通过信息无助任务（实验2）操纵的稳定控制感剥夺均未阻碍随后的刷新任务;但在不稳定控制感剥夺的条件下（实验2）,刷新任务的成绩显著降低。这表明,控制感剥夺对工作记忆刷新功能的影响依赖于对其操纵的稳定性。     

One-year temporal stability and predictive and incremental validity of the Body,Eating, and Exercise Comparison Orientation Measure (BEECOM) among college women

This study examined the one-year temporal stability and the predictive and incremental validity of the Body, Eating, and Exercise Comparison Measure (BEECOM) in a sample of 237 college women who completed study measures at two time points about one year apart. One-year temporal stability was high for the BEECOM total and subscale (i.e., Body, Eating, and Exercise Comparison Orientation) scores. Additionally, the BEECOM exhibited predictive validity in that it accounted for variance in body dissatisfaction and eating disorder symptomatology one year later. These findings held even after controlling for body mass index and existing measures of social comparison orientation. However, results regarding the incremental validity of the BEECOM, or its ability to predict change in these constructs over time, were more mixed. Overall, this study demonstrated additional psychometric properties of the BEECOM among college women, further establishing the usefulness of this measure for more comprehensively assessing eating disorder-related social comparison.     

Type D personality,but not Type A behavior pattern,is associated with coronary plaque vulnerability

Personality traits are associated with major adverse coronary events (MACE) in patients with coronary artery disease (CAD). However, the link between personality traits and intravascular morphology in CAD patients is poorly understood. This study investigated the relationship between personality traits, specifically Type A behavior pattern and Type D personality, and plaque vulnerability. After adjustment for demographic and clinical factors, multivariable regression analysis showed no association between Type A and optical coherence tomography indices. However, Type D personality was independently associated with lipid plaque, thin cap fibroatheroma (TCFA), and fibrous cap thickness. More specifically, negative affectivity of Type D was related to lipid plaque, TCFA and fibrous cap thickness, and social inhibition was associated with plaque rupture. Our results show that Type D personality was associated with plaque vulnerability, independent of clinical factors. Measurement of negative affectivity and social inhibition will increase our understanding of the progressive phase of the plaque vulnerability, which can contribute to the early identification of high risk patients and reduce the incidence of MACE.     

Transient Effects of Gaze Stability Exercises on Postural Stability in Patients With Posterior Circulation Stroke

The authors sought to investigate if short-term gaze stability exercises have an effect on postural stability of dynamic standing during neck movement in patients with posterior circulation stroke (PCS). Patients in both PCS and non-PCS groups were assigned to either an intervention or control group. The intervention group performed the gaze stability exercises for 10 min while the control group was merely resting. The center of pressure velocity was calculated to evaluate the postural stability. After intervention, PCS and non-PCS showed a significant reduction in center of pressure velocity during dynamic standing with eyes closed condition, and the PCS group showed a significant improvement in eye-opened condition. This study indicated that gaze stability exercises improve PCS patients' postural control, especially during dynamic standing.     

Linear instability signals the initiation of motion of a twin plane under load

This letter presents a study of the atomic mechanism of the initiation of motion of a static twin plane under applied mechanical load in a model shape-memory material. By tracking the deformation under load and using linear stability analysis, we find that the eigenvalues of the Hessian matrix provide an indicator of the initiation of motion of the twin plane. The initiation of motion is signaled by a linear instability and a drop in the lowest eigenvalue to zero as well as a sharp drop in higher eigenvalues. Additionally, by comparing with direct molecular dynamics, we see that the eigenmode associated with the zero eigenvalue is found to accurately predict the initial mode of motion. We also find that the initial motion occurs through the formation of a stacking fault just ahead of the existing twin plane and the broadening of the stacking fault drives further transformation.     

Examining the long-term stability of overgeneral autobiographical memory

Overgeneral autobiographical memory (OGM) is a proposed trait-marker for vulnerability to depression, but relatively little work has examined its long-term stability. This study investigated the stability of OGM over several years in 271 late adolescents and young adults participating in a larger longitudinal study of risk for emotional disorders. The Autobiographical Memory Test (AMT) was administered twice, with test–retest intervals ranging from approximately 3 to 6 years. There was evidence of significant but modest stability in OGM over several years. Specifically, Spearman rank correlations (ρs) between the proportions of specific and categoric memories generated on the two AMTs were .31 and .32, respectively. We did not find evidence that the stability of OGM was moderated by the length of the test–retest interval. Furthermore, the stability coefficients for OGM for individuals with and without a lifetime history of major depressive disorder (MDD) were relatively similar in magnitude and not significantly different from one another (ρs=.34 and .42 for the proportions of specific and categoric memories for those with a history of MDD; ρs=.31 for both the proportions of specific and categoric memories for those without a history of MDD). Implications for the conceptualisation of OGM are discussed.     

Variations in Linear and Nonlinear Postural Measurements under Achilles Tendon Vibration and Unstable Support-Surface Conditions

Reduced support-surface stability has been shown to attenuate the effect of Achilles tendon vibration on backward body displacement. In the present study, 20 participants performed a quiet, upright standing task on a stable and sway-referenced support, with and without vibration. The authors calculated equilibrium scores (ES), approximate entropy (ApEn), and mean and peak power spectral density frequencies of center-of-pressure variations. It was found that ES values decreased with the addition of vibration and in the sway-referenced support condition. ApEn values decreased with the addition of vibration but only with a stable support. Conversely, mean and peak frequencies increased with the addition of vibration, independent of support stability. These results suggest that the role of ankle proprioceptive input changes depending on support-surface characteristics and demonstrate the value of using both linear and nonlinear measures of postural sway.