The Effect of Fatigue on Learning and Performance of a Gross Motor Task

40 college males were sequentially assigned to 1 of 2 groups to examine the effects of induced physical fatigue upon the performance and learning of a gross motor task, the stabilometer. All Ss were given 32 practice trials over 3 practice sessions, with 48 hr. rest interpolated between sessions. Trials 1 and 2 were performed under control conditions (no fatigue) for both groups. The Experimental Group was then required to perform under conditions of physical fatigue during Trials 3-26. Trials 27-32 (Session 3) were performed under control conditions. The condition of fatigue was achieved on Trials 3-26 by having Ss pedal a bicycle ergometer until a heart rate of 180 beats/min was attained prior to each trial. The Control Group cancelled vowels. The results indicated that physical fatigue was detrimental to the performance and learning of the Experimental Group.     

Mass Perturbation of a Body Segment: 2. Effects on Interlimb Coordination

The shifts in relative phase that are observed when rhythmically coordinated limbs are submitted to asymmetric mass perturbations have typically been attributed to the induced eigenfrequency difference ($DL$oM) between the limbs. Modeling the moving limbs as forced linear oscillators, however, reveals that asymmetric mass perturbations may induce a difference not only in eigenfrequency (i.e., $DL$oM $$ 0) but also in the covarying low-frequency control gains (i.e., $DLk $$ 0). Because the inverse of the lowfrequency control gain (k) reflects the level of muscular torque (input) required for a particular displacement from equilibrium (output), asymmetric mass perturbations may result in an imbalance in the muscular torques required for task performance (related to $DLk $$ 0). Thus, it is possible that the effects attributed to $DL$oM were in fact mediated by $DLk. In 2 experiments, the authors manipulated $DLk and $DL$oM separately by applying mass perturbations to the lower legs of 9 participants. The relative phasing between the legs was not affected by $DLk, but manipulation of $DL$oM (while $DLk remained approximately 0) induced systematic relative phase shifts that were more pronounced for antiphase than for in-phase coordination. That indication that the coordination dynamics is indeed influenced by an imbalance in eigenfrequency is discussed vis-à-vis the question of how such a merely peripheral property may affect the underlying coordination process.     

Psychophysics of Kinesthesis

A horizontal straight-arm movement was used to determine the relationship between the physical stimulus continuum and the psychological continuum of kinesthetic extent of arm movement. A power function with an exponent of 1.075 best described this relationship. In addition, to classify extent of movement as belonging to either a prothetic or metathetic continuum, the category scale was derived. According to the functional criteria described by Stevens (1957), extent of movement was subserved by a metathetic process which would indicate that, for the present task, judgments were made through the use of positional cues rather than amplitude cues.     

Effects of Classically Differentiated Supplementary Feedback Cues on Tracking Skill

Although previous studies had shown that classical predifferentiation of green (CS-j and red (CS+) cues enabled them to facilitate tracking performance when used as supplementary indicators of correct and incorrect responses respectively, the studies were inconclusive concerning specific conditional properties versus nonspecific arousal consequences of the cues. A sample of 108 Ss was exposed to the same predifferentiation procedure, but then were subgrouped in terms of the kind of feedback signal received in tracking (no signal, red only, green only, both signals). A nonspecificity theory predicts subgroup equality of tracking performances while specificity theory predicts the dependence of performance level on the kind of signal received. Results corroborated previous findings and the view that tracking effects were reasonably attributable to the transfer of specific stimulus functions generated in the differentiation trials.     

Perceptual Estimates of Motor Skill Proficiency Are Constrained by the Stability of Coordination Patterns

This study demonstrated that motor skill proficiency ratings are constrained by the same order parameter dynamics that constrain action production and action perception processes. Participants produced rhythmic actions simulated by an animated stick figure of the human arm. The primary finding was that participants’ proficiency ratings covaried most with relative phase (φ) variability compared to mean relative phase. In-phase (φ = 0°) was produced with the least variability and received the highest proficiency rating, whereas the patterns φ = ±150° were attempted with the most variability and received the lowest proficiency ratings. A temporal delay in attempting to produce the animated pattern had a large impact on produced relative phase, yet had little impact on the proficiency ratings. Proprioceptive processes provide individuals information on motor skill proficiency. The lead or lag motion of the hand to forearm segment of the animated arm was identified consistently through visual processes and revealed asymmetries in the mapping of visual input to motor output. The results are consistent with concepts from the dynamic pattern theory of coordination and are discussed with regard to relative phase as an informational variable that constraints the perception-action system across many levels.     

Father Involvement in Parent Training for Oppositional Child Behavior

Outcome literature (1981 to 1988) on behavioral parent training interventions for nonhandicapped children with oppositional behavior is reviewed to assess the extent and effects of father involvement in parent training. Thirteen studies were found that included some father involvement. Weaknesses of these studies include a failure to observe and measure changed in father-child interactions, a lack of emphasis on the impact of the marital relationship, a lack of attention to similarities in parental child management strategies, and a lack of assessment of paternal characteristics. Further research to assess the effects of including fathers on parent training outcomes can improve the efficiency and effectiveness of these interventions.     

Fostering Students’ Appraisals of the Relevance of History by Comparing Analogous Cases of an Enduring Human Issue: A Quasi-Experimental Study

To identify the challenges that students must meet to engage in effective self-directed inquiry, a class was followed for three years, from the fourth through the sixth grades, as they engaged in a sequence of progressively more demanding inquiry activities. Students made substantial progress in understanding the objectives of inquiry, identifying questions, attending to evidence, identifying patterns, making controlled comparisons, interpreting increasingly complex data, supporting claims, and drawing justified conclusions. Retaining awareness of inquiry objectives and integrating influences of multiple variables in predicting outcomes were two areas that remained challenging. A comparison group of seventh graders who had not been involved in the program displayed strikingly different approaches to an inquiry task, indicating that the skills identified here are not ones that develop in the absence of appropriate kinds of educational experiences.     

Achievement emotions in elementary,middle, and high school: How do students feel about specific contexts in terms of settings and subject‐domains?

The present work investigates students' representation of achievement emotions, focusing in context‐specific situations in terms of settings and subject‐domains, as a function of grade level. We involved 527 fourth‐, seventh‐, and eleventh‐graders, who evaluated ten discrete emotions through questionnaires, with reference to verbal language and mathematics, and different settings (class, homework, tests). Confirmatory multitrait‐multimethod analyses indicated higher salience of subject‐domains rather than settings for all the emotions; however, complexity of reality was best explained when also settings were accounted for. Analyses of variance revealed higher intensity of positive emotions for younger students, and the opposite pattern for older students; significant differences for most of the emotions based on the evaluative nature of settings, moderated by class levels; more intense positive emotions for mathematics and more intense negative emotions for Italian. Results are discussed considering their theoretical and applied relevance, corroborating previous literature on domain‐specificity.     

Mindfulness-based cognitive therapy for the treatment of current depressive symptoms: a meta-analysis

ABSTRACT

Mindfulness-based cognitive therapy (MBCT) appears to be a promising intervention for the prevention of relapse in major depressive disorder, but its efficacy in patients with current depressive symptoms is less clear. Randomized clinical trials of MBCT for adult patients with current depressive symptoms were included (k = 13, N = 1046). Comparison conditions were coded based on whether they were intended to be therapeutic (specific active controls) or not (non-specific controls). MBCT was superior to non-specific controls at post-treatment (k = 10, d = 0.71, 95% confidence interval [CI] [0.47, 0.96]), although not at longest follow-up (k = 2, d = 1.47, [?0.71, 3.65], mean follow-up = 5.70 months across all studies with follow-up). MBCT did not differ from other active therapies at post-treatment (k = 6, d = 0.002, [?0.43, 0.44]) and longest follow-up (k = 4, d = 0.26, [?0.24, 0.75]). There was some evidence that studies with higher methodological quality showed smaller effects at post-treatment, but no evidence that effects varied by inclusion criterion. The impact of publication bias appeared minimal. MBCT seems to be efficacious for samples with current depressive symptoms at post-treatment, although a limited number of studies tested the long-term effects of this therapy.     

论宏观经济调控和管理中的若干伦理问题

宏观经济调控和管理中的伦理问题,是一个不可忽视的领域。中国是一个发展中国家,正处在从传统经济向现代市场经济转型,政府的宏观调控不可或缺;同时政府作为经济活动的主体,其行为也必须遵守适应市场经济运作的规则。