Role of the inertial eigenvectors in proprioception near the limits of arm adduction range of motion

Common everyday activities such as reaching for a cup, combing one's hair, or positioning a tool involve the accurate registration of the limb's orientation relative to the body and the environment. Past work has demonstrated that the ability of humans to perceive the spatial orientation of an occluded arm is tied to the arm's inertial eigenvectors, invariant mechanical parameters corresponding to a limb's axes of rotational symmetry. In a recent study participants pointed to visible targets while the arms' inertial eigenvectors were displaced by asymmetrically weighted splints. The lack of an effect of those splints on pointing error led them to conclude that inertial eigenvectors are not the primary invariants used for proprioception. However, their data suggested an effect of the eigenvectors, but only for conditions in which pointing did not require placing the arm near the limits of shoulder adduction range of motion. In the present study we found a significant effect of displacing the eigenvector for all tested arm angles, regardless of degree of shoulder adduction. Overall, the results supported the hypothesis that proprioception is based on sensitivity to the limb's inertial eigenvectors, with no reduction of the eigenvector effect when adducting the arm so as to reach far across the body midline.     

Up and down in middle age: monotonic and nonmonotonic changes in roles, status, and personality

It is proposed that personality (conceptualized in terms of motives and psychological resources) changes normatively not only from young adulthood to middle age but also within middle age and that these changes take place in relation to social and biosocial change over the same period. Data from 123 women studied at ages 27, 43, 52, and 61 largely supported hypotheses about change in social roles, status, health, motives, personality characteristics, emotion regulation, and relationships. Noteworthy aspects of the findings were substantial curvilinear change within middle age and associations of work involvement and physical health with personality change during late middle age.     

Internal consistency reliability of the Francis Scale of Attitude toward Alcohol among adolescents in Northern Ireland

The Francis Scale of Attitude toward Alcohol was completed by 324 adolescents (M= 17.1 yr., SD=3.6) in Northern Ireland to examine reliability of the measure among this age group. These data support its internal consistency (.89) and suggest that the Francis Scale of Attitude toward Alcohol is psychometrically appropriate for use among this age group.     

Distress tolerance as a predictor of early treatment dropout in a residential substance abuse treatment facility

A large percentage of individuals who enter residential substance abuse treatment drop out before completing treatment. Given that early treatment dropout places individuals at an increased risk for relapse, identifying the mechanisms underlying treatment dropout would have several important theoretical and clinical implications. In the current study, the authors examined levels of psychological and physical distress tolerance as a predictor of early treatment dropout in a residential substance abuse treatment facility. In a sample of 122 individuals entering a residential substance abuse treatment facility, level of psychological distress tolerance was predictive of early treatment dropout above and beyond relevant self-report variables. There was no relationship between physical distress tolerance and early treatment dropout. Implications for future studies and treatment development or modification are discussed.     

The relationship between short-term memory and working memory: complex span made simple?

This experiment addresses the question of what makes a working memory measure a good predictor of higher-level abilities. Verbal and visuospatial processing episodes were interleaved with distinct verbal and visuospatial storage episodes to form four complex span tasks. Although these measures were reliable predictors of reading and mathematics ability in children, they were no more predictive of these abilities than corresponding simple span tasks involving storage alone. However, when individual differences in storage ability and processing capacity were controlled for, residual variance in complex span performance was related to academic ability in some cases. These findings indicate that complex span tasks are multiply determined, and that differences in task structure can dramatically influence the relative importance of these multiple constraints and the predictive power of a complex span measure.     

Gender differences in leg stiffness and stiffness recruitment strategy during two-legged hopping

The authors compared leg stiffness (K(VERT)), muscle activation, and joint movement patterns between 11 men and 10 women during hopping. Physically active and healthy men and women performed continuous 2-legged hopping at their preferred rate and at 3.0 Hz. Compared with men, women demonstrated decreased K(VERT); however, after the authors normalized for body mass, gender differences in K(VERT) were eliminated. In comparison with men, women also demonstrated increased quadriceps and soleus activity, as well as greater quadriceps-to-hamstrings coactivation ratios. There were no significant gender differences for joint movement patterns (p>.05). The relationship between the observed gender differences in muscle recruitment and the increased risk of anterior cruciate ligament injury in women requires further study.