Specificity of Task Constraints and Effects of Visual Demonstrations and Verbal Instructions in Directing Learners' Search During Skill Acquisition

In the present study, the efficacy of visual demonstrations and verbal instructions as instructional constraints on the acquisition of movement coordination was investigated. Fifteen participants performed an aiming task on 100 acquisition and 20 retention trials, under 1 of 3 conditions: a modeling group (MG), a verbally directed group (VDG), and a control group (CG). The MG observed a model intermittently throughout acquisition, whereas the VDG was verbally instructed to use the model's movement pattern. Participants in the CG received neither form of instruction. Kinematic analysis revealed that compared with verbal instructions or no instructions, visual demonstrations significantly improved participants' approximation of the model's coordination pattern. No differences were found in movement outcomes. Coordination data supported the visual perception perspective on observational learning, whereas outcome data suggested that the modeling effect is mainly a function of task constraints, that is, the novelty of a movement pattern.     

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.     

Relations Between Parenting Behavior and SES in a Clinical Sample: Validity of SES Measures

Two common methods of measuring socioeconomic status (SES) were examined in relation to observed parenting behaviors in a clinical sample of 89 mothers of 3- to 6-year-olds referred for treatment of oppositional defiant disorder. Families were 74% Caucasian, 9% African American, 5% Hispanic, 1% Asian, and 11% Biracial. Most children were male (75%). Parenting behaviors were measured with the Dyadic Parent–Child Interaction Coding System (DPICS) categories of prosocial talk and negative talk. Analyses were conducted with SES measured in two ways: (a) the Hollingshead Four-Factor Index of Social Status (HI) was correlated with parenting behaviors; and (b) family income, parent education (5 categories), and parent occupation (5 categories) were used to predict parent behavior. SES was significantly positively related to maternal prosocial talk. When SES was operationalized as income, occupation, and education, the model predicted three times more variance in maternal prosocial talk than the HI alone. SES was not related to maternal negative talk by either measure of SES.     

Contextual analysis of home environment factors influencing the acquisition of early reading skills in Zambian families

This study examined the effect of home environment factors in the acquisition of early reading skills (orthographic awareness and decoding competence). To assess these factors, a sample of seventy-two (72) first grade learners (females?=?55%; age range?=?7–8 years) and their maternal parents (age range 26–61 years old) from low SES in Zambia's capital city, Lusaka were recruited. Parents, in response to a home literacy questionnaire, reported on their attitudes towards reading, literacy teaching in the home, the home literacy environment, presence of reading materials for adults and children, parental education, occupation, family size and family possessions. Two measures of reading skill were administered at school. Correlations revealed that parental education, occupation and the size of the family were not significantly associated with the reading measures. Family possessions, parental reading attitudes, literacy activities, and reading materials significantly predicted orthographic awareness. In predicting decoding competence, only family possessions, parental reading attitudes and literacy activities were predictive. Regardless of the context, children experience literacy in varied forms and quantities.     

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.     

Understanding money's limits: People's beliefs about the income – Happiness correlation

It is claimed that the correlation between income and happiness is considerably weaker than people expect and recent research supports that contention. However, an important lesson from judgment and decision-making research is that judgments are constructed in response to the prevailing context, leaving open the possibility that some elicitation procedures may reveal accurate intuitions about income and happiness. We examined whether this is so. Study 1 participants ranked a set of empirical relationships according to the strength of correlation and we examined whether they ranked the income–happiness link where it actually falls in the set. In Studies 2 and 3, participants estimated the probability that someone with a higher income than another is also the happier of the two. The estimates of the participants were then compared to the actual probability based on the documented income–happiness relationship. Results indicate that, using these elicitation procedures, people have an accurate understanding of the relationship between income and happiness.