Free(z)ing Degrees of Freedom in Skill Acquisition

This study reports an empirical investigation into Bernstein's (1967) ideas that in the early stages of the acquisition of a movement skill the coordination problem is reduced by an initial freezing out of degrees of freedom, followed later in the learning process by the release of these degrees of freedom and their incorporation into a dynamic, controllable system. “Freezing” degrees of freedom was made operational both as a rigid fixation of individual degrees of freedom and as the formation of rigid couplings between multiple degrees of freedom. Five subjects practiced slalom-like ski movements on a ski apparatus for 7 consecutive days. Results showed that at the early phases of learning, the joint angles of the lower limbs and torso displayed little movement, as expressed by their standard deviations and ranges of angular motion, whereas joint couplings were high, as shown by the relatively high cross correlations between joint angles. Over practice, angular movement significantly increased in all joint angles of the lower limbs and torso, although the cross correlations decreased. Support for the processes of freezing and releasing degrees of freedom was thus given at both levels of operationalization. In addition, a consistent change from laterally symmetric to laterally asymmetric cross-correlation patterns were observed as a function of practice. Overall, the findings provide empirical support for Bernstein's ideas regarding the mastery of redundant degrees of freedom in the acquisition of coordination.     

Acquisition of Effector-Specific and Effector-Independent Components of Sequencing Skill

In a serial reaction time task, participants practiced a repeating sequence with 1 hand. In interleaved blocks, they responded to random sequences with the other hand. Experiment 1 was composed of 5 sessions, each consisting of 30 blocks. Intermanual transfer, reflecting a hand-independent component of sequence knowledge, increased across session. A smaller but significant, nontransferable, and hand-specific component was evident in each session and did not increase with practice. Experiment 2 comprised only 1 session. Uninterrupted practice (no interleaved random blocks) improved hand-independent sequence learning in comparison with interrupted practice (as implemented in Experiment 1), whereas hand-specific sequence learning was unaffected by this between-subjects manipulation. These findings suggest separate mechanisms for effector-independent sequence learning and effector-specific acquisition of optimized response coarticulation.     

Effects of Instructor Attractiveness on Learning

Although a considerable body of research has examined the impact of student attractiveness on instructors, little attention has been given to the influence of instructor attractiveness on students. This study tested the hypothesis that persons would perform significantly better on a learning task when they perceived their instructor to be high in physical attractiveness. To test the hypothesis, participants listened to an audio lecture while viewing a photograph of instructor. The photograph depicted either a physically attractive instructor or a less attractive instructor. Following the lecture, participants completed a forced choice recognition task covering material from the lecture. Consistent with the predictions; attractive instructors were associated with more learning. Finally, we replicated previous findings demonstrating the role attractiveness plays in person perception.     

Prereading skills of very-low-birth-weight prematurely born Finnish children

Our objective was to study the prereading skills of very-low-birth-weight (VLBW; ≤ 1500 g) prematurely born children at the age of five years. A regional cohort of 89 VLBW children and 152 full-term (FT) born children was assessed for letter knowledge, phonological processing, and speeded naming. Full-scale IQ (FSIQ) was assessed using a short version of WPPSI-R. The associations of parental and neonatal factors, and FSIQ with prereading skills were assessed. VLBW group had poorer prereading skills, and there were more VLBW children at-risk (performing < ?1 SD) compared to FT children in phonological processing (23% vs. 9%, p = .002), letter knowledge (27% vs. 14%, p = .017), and the accuracy of speeded naming (26% vs. 13%, p = .020). VLBW children had lower average FSIQ and Performance IQ (both comparisons p < .001) than FT controls, but Verbal IQ did not differ. When FSIQ was used as a covariate, VLBW children did not differ from the FT group in prereading skills indicating that they are at risk for more global developmental problems. Lower parental level of education as well as parent's reading problems were negatively associated with VLBW children's prereading skills. Positively, about 75% of VLBW children performed within the normal range in each individual prereading skill.     

数学焦虑对工作记忆子系统及数学心算的影响分析

本研究从工作记忆容量的角度入手,探讨数学焦虑对工作记忆子系统及数学心算成绩的影响,并寻求三者之间关系的理论解释。本研究为3×2×2混合实验设计,即三组被试（高、中、低数学焦虑组）、工作记忆两个子系统（言语工作记忆和视空间工作记忆）和两种数学心算任务难度,并记录数学心算的反应时和正确率作为其成绩指标。结果表明在要求较高工作记忆容量的数学心算任务中,数学焦虑通过言语工作记忆和视空间工作记忆都会对数学心算成绩产生影响,其中视空间工作记忆是数学焦虑与复杂数学心算反应时之间的中介变量。     

Causality and the categorisation of objects and events

The “Tower of London” puzzle was adapted to tablet PCs to be used as a clinical bedside test. “Iso-problems”, a specific class of problems, require identical moves but ball colours are permuted. Thus difficulty is the same even if the appearance is different. We wanted to determine the impact of these as yet little-studied tasks and hypothesised that there may be a learning effect specific to them (the “iso-effect”). We interspersed a set of six iso-problems within one selection of 22 tasks and analysed problem solving by 81 healthy adults (mean age 41.6 years). Participants showed learning across iso-problems (less time, fewer moves, increasingly efficient solutions). This effect was distinct from general learning, as was obvious from comparison with a series of non-isomorphic tasks. However, participants seem not to be aware of solving such problems. This “iso-effect” may be related to implicit memory, a domain that so far has not been assessed using the Tower of London.     

When modesty wins: Impression management through modesty,political skill,and career success—a two-study investigation

The purpose of this research is to investigate the effect of employees' upward self-presentation through modesty and political skill on their subsequent career success. Study 1 used a predictive design over a 3 year period with 141 employees, controlling for age, gender, and self-esteem. Political skill positively moderated the relationship between employees' upward modesty and career success (attained position, career satisfaction) after 3 years. Study 2 (n = 132 employees) provided construct validation, demonstrating high discriminant validity of the impression management through modesty scale used in Study 1 with a trait-modesty scale, thus attenuating rival explanations of the findings in Study 1. Implications, limitations, and future directions for research are discussed.     

Effects of Item Difficulty on the Retrieval of Solutions during Cognitive Skill Acquisition: Age Differences

ABSTRACT

In cognitive skill learning, shifts to better strategies for obtaining solutions often occur while associations between problems and solutions are being strengthened. In two skill learning experiments, we examined the effects of item difficulty on the retrieval of solutions and the learning of problem–solution associations in younger and older adults. The results of both experiments demonstrated an ‘easy effect’ in both younger and older adults, such that the retrieval of solutions as well recognition memory for problems was best for the easier items. In addition, a ‘hard effect’ was found in younger adults, but not in older adults, whereby the retrieval of solutions as well as recognition memory for problems was better for harder items than for medium-difficulty items. The finding that increased computational demands at the item level delayed item memorization and the retrieval of solutions in older adults but not younger adults is consistent with a general-resources account of age-related differences in skill learning.     

Noise on, voicing off: Speech perception deficits in children with specific language impairment

Speech perception of four phonetic categories (voicing, place, manner, and nasality) was investigated in children with specific language impairment (SLI) (n = 20) and age-matched controls (n = 19) in quiet and various noise conditions using an AXB two-alternative forced-choice paradigm. Children with SLI exhibited robust speech perception deficits in silence, stationary noise, and amplitude-modulated noise. Comparable deficits were obtained for fast, intermediate, and slow modulation rates, and this speaks against the various temporal processing accounts of SLI. Children with SLI exhibited normal “masking release” effects (i.e., better performance in fluctuating noise than in stationary noise), again suggesting relatively spared spectral and temporal auditory resolution. In terms of phonetic categories, voicing was more affected than place, manner, or nasality. The specific nature of this voicing deficit is hard to explain with general processing impairments in attention or memory. Finally, speech perception in noise correlated with an oral language component but not with either a memory or IQ component, and it accounted for unique variance beyond IQ and low-level auditory perception. In sum, poor speech perception seems to be one of the primary deficits in children with SLI that might explain poor phonological development, impaired word production, and poor word comprehension.