Effect of Transient Perturbations of Short-Term Memory on Target-Directed Blind Locomotion

It is difficult to walk without vision to a nearby destination if there is a time delay between watching the destination and walking toward it. Indeed, path deviation occurred when delays were introduced before initiating straight ahead blindfolded walking (R. A. Tyrrell, K. K., Rudolph, B. G., Eggers, &; H. W. Leibowitz, 1993 Tyrrell, R. A., Rudolph, K. K., Eggers, B. G., &; Leibowitz, H. W. (1993). Evidence for the persistence of visual guidance information. Perception &; Psychophysics, 54, 431–438.[Crossref], [PubMed] , [Google Scholar]). The questions are whether the location of a 60-s delay in the walking path and whether performing a cognitive task during the delay influence the accuracy in reaching a previously seen target while walking without vision. Thirty young adults walked blindfolded and stopped when they believed they had reached a target at 8 m. Delays were 60 s in duration, were located at 0, 4, and 7 m, and involved waiting or backward counting. Significant differences were found between 0-m and 4-m delay locations for distance to target, distance travelled and path deviation (p < .05). Significant effect of backward counting during the 60-s delay was found at the 0-m delay for distance travelled (p < .05). The interaction between retaining visual guidance information during 60 s and performing a cognitive task likely influenced target-directed blind navigation.     

Coordination Between Arm and Leg Movements During Locomotion

To evaluate the contrasting dynamical and biomechanical interpretations of the 2:1 frequency coordination between arm and leg movements that occurs at low walking velocities and the 1:1 frequency coordination that occurs at higher walking velocities, the authors conducted an experiment in which they quantified the effect of walking velocity on the stability of the frequency and phase coordination between the individual limb movements. Spectral analyses revealed the presence of 2:1 frequency coordination as a consistent feature of the data in only 3 out of 8 participants at walking velocities ranging from 1.0 to 2.0 km/h, in spite of the fact that the eigenfrequencies of the arms were rather similar across participants. The degree of interlimb coupling, as indexed by weighted coherence and variability of relative phase, was lower for the arm movements and for ipsilateral and diagonal combinations of arm and leg movements than for the leg movements. Furthermore, the coupling between all pairs of limb movements was found to increase with walking velocity, whereas no clear signs were observed that the switches from 2:1 to 1:1 frequency coordination and vice versa were preceded by loss of stability. Therefore, neither a purely biomechanical nor a purely dynamical model is optimally suited to explain these results. Instead, an integrative model involving elements of both approaches seems to be required.     

Personality Factors and the Short-Term Variability in Subjective Well-Being

The present study used a sample of 60 college students and an intensive longitudinal approach to investigate the variability in subjective well-being (SWB). At the beginning of the semester students provided information related to their personalities, while throughout the semester they provided SWB data on a weekly basis. Considerable between-student and within-student variability in SWB was found. Multiple regression analyses revealed that personality-based models were useful in explaining the variability in SWB. Conscientiousness and the Chance component of locus of control were found to be statistically significant independent personality predictors of variability in SWB. Specifically, students high in conscientiousness and high in external locus of control experienced more variability in SWB over the study period.     

Local Dynamic Stability of the Locomotion of Lower Extremity Joints and Trunk During Backward Upslope Walking

Backward slope walking was considered as a practical rehabilitation and training skill. However, its gait stability has been hardly studied, resulting in its limited application as a rehabilitation tool. In this study, the effect of walking direction and slope grade were investigated on the local dynamic stability of the motion of lower extremity joints and trunk segment during backward and forward upslope walking (BUW/FUW). The local divergence exponents (λ_S) of 16 adults were calculated during their BUW and FUW at grades of 0%, 5%, 10%, and 15%. Mean standard deviation over strides (MeanSD) was analyzed as their gait variability. Backward walking showed larger λ_S for the abduction-adduction and rotational angles of knee and ankle on inclined surface than forward walking, while λ_S for hip flexion-extension angle at steeper grades was opposite. No grade effect for any joint existed during BUW, while λ_S increased with the increasing grade during FUW. As to the trunk, walking direction did little impact on λ_S. Still, significant larger λ_S for its medial-lateral and vertical motion were found at the steeper grades during both FUW and BUW. Results indicate that during BUW, the backward direction may influence the stability of joint motions, while the trunk stability was challenged by the increasing grades. Therefore, BUW may be a training tool for the stability of both upper and lower body motion during gait.     

Imitation and Creativity: Beneficial Effects of Propulsion Strategies and Specificity

Prior studies examining imitation of exemplar solutions have produced a mixed pattern of findings with some studies indicating that exemplar imitation contributes to creative problem‐solving and other studies indicating that it may inhibit creative problem‐solving. In the present effort, it is argued that the effects of exemplar imitation on creative problem‐solving depend on the strategies people use when working with exemplars. In the present study, people were asked to provide advertising campaigns in response to a marketing problem. Prior to starting work on this problem, manipulations were made in exemplar content. Imitation strategies used in problem‐solving, for example, forward incrementation, and redefinition, were assessed. It was found that imitation strategies were strongly related to the production of higher quality, more original, and more elegant advertising campaigns. Moreover, use of these strategies was facilitated when more specific information was presented in exemplar solutions. The implications of these findings for understanding the role of imitation in creative problem‐solving are discussed.     

Coordination of Eye and Leg Movements During Visually Guided Stepping

In the present study, 2 related hypotheses were tested: first, that vision is used in a feedforward control mode during precision stepping onto visual targets and, second, that the oculomotor and locomotor control centers interact to produce coordinated eye and leg movements during that task. Participants' (N = 4) eye movements and step cycle transition events were monitored while they performed a task requiring precise foot placement at every step onto irregularly placed stepping stones under conditions in which the availability of visual information was either restricted or intermittently removed altogether. Accurate saccades, followed by accurate steps, to the next footfall target were almost always made even when the information had been invisible for as long as 500 ms. Despite delays in footlift caused by the temporary removal (and subsequent reinstatement) of visual information, the mean interval between the start of the eye movement and the start of the swing toward a target did not vary significantly (p > .05). In contrast, the mean interval between saccade onset away from a target and a foot landing on that target (stance onset) did vary significantly (p < .05) under the different experimental conditions. Those results support the stated hypotheses.     

Development of Postural Adjustment During Gait Initiation: Kinematic and EMG Analysis

The authors studied the development of postural adjustments associated with the initiation of gait in children by using kinematic and electromyographic (EMG) analysis. Participants (N = 28) included infants with 1-4 and 9-17 months of walking experience, children 4-5 years of age, and adults. Anticipatory postural adjustments (APA) were present in the youngest age groups, including a clear anticipatory lateral tilt of the pelvis and the stance leg, which enabled the child to unload the opposite leg shortly before its swing phase. An anticipatory activation of the hip abductor of the leg in stance phase prior to heel-off was found, suggesting pelvis stabilization. APA did not appear consistently until 4-5 years of age. A decrease in segmental oscillations occurred across the ages, indicating better control of intersegmental coordination in the frontal and sagittal planes during the postural phase of gait initiation. Young walkers presented APA involving movements of both the upper and the lower parts of the body, whereas, like adults, 4- to 5-year-olds were able to laterally shift only the pelvis and the stance leg. The oldest children and the adults also showed lower activation levels of hip and knee muscles but higher activation at the ankle level. Those kinematic and EMG results taken together suggest a clear developmental sequence from an en bloc operation of the body through an articulated operation with maturation, walking experience, or both.     

Effect of Nonspecific Chronic Low Back Pain on Walking Economy: An Observational Study

The authors investigated the effects of chronic low back pain (LBP) and walking speed (WS) on metabolic power and cost of transport (CT). Subjects with chronic nonspecific LBP (LBP group [LG]; n = 9) and healthy (control group [CG]; n = 9) were included. The test battery was divided into 3 blocks according to WS as follows: preferred self-selected speed (PS), and lower and higher than the PS. In each block, the volunteers walked 5 min, during which oxygen consumption was measured. Although without differences between groups, the LG had CT lower in slower speeds than in faster speeds. Walking speed affected CT only in the LG, which the group had the greatest walking economy at slower speeds.     

The Effect of Age on Relative Timing Variability and Transfer

The purpose of this study was to investigate potential qualitative differences in relative timing across age both within and across speed conditions. Forty right-handed males performed 48 trials of a five-component coincident-timing task at one speed and then 16 more at a different speed. The independent variables were age (5-7, 8-10, 11-13 years, and adult), speed (slow and fast), and block order (training and transfer). The results indicated that within-speed relative timing consistency improved with increasing age for movement-time and pause-time components, while a cross-speed transfer improved with age only for pause time. Movement velocity emerged as a more stable timing parameter than movement time across speeds for all groups. The last movement-time component correlated highly with the total response times, suggesting that coincident-timing accuracy was controlled to a large degree by a final, fine-tuning correction. These results imply that developmental deficits in relative timing increase the attention demands of a given task, thereby reducing a child’s capacity to concurrently control his movements and monitor events in the environment.     

Effect of Heel Heights on Female Postural Control During Standing on a Dynamic Support Surface With Sinusoidal Oscillations

The authors aimed to investigate female balance or stability control with comparative analysis of the center of pressure trajectory and plantar pressure distribution with different high-heeled shoes while standing on a dynamic surface with multidirectional perturbations. College females with at least 2 years' history of wearing high-heel shoes voluntarily participated in the test with a Novel Pedar insole (Novel, GmBH, Munich, Germany. With heels height increasing, the pressure time integral obviously transfer to the medial forefoot region, with center of pressure trajectory medially deviated significantly, either under anteroposterior or mediolateral perturbations. The passive plantarflexion position of ankle incurred by high heel increased the range of motion in the frontal plane but decreased ankle stability, thus increasing the challenge of body balance maintenance.     

奖惩线索对停止信号任务中抑制能力和心率、皮肤电的影响

采用不同类型强化刺激(中性刺激,奖励刺激,惩罚刺激,以及奖励、惩罚刺激并存)来改变可获得奖励和惩罚的强度和频度,分别考察不同类型强化条件对停止信号任务中抑制能力、心率和皮肤电的影响.结果显示:与奖惩混合条件相比,在奖励条件下,被试的反应速度快,但正确抑制率明显低于惩罚条件和奖惩混合条件;在奖励条件下,被试在任务完成过程中的心率明显高于反馈条件、惩罚条件和奖惩混合条件.四种条件下被试的皮肤电活动无差异.     

The Effects on Skill Acquisition of an Interpolated Motor Short-Term Memory Task During The Kr-Delay Interval

The effects of an interpolated motor short-term memory task during the KR-delay interval on skill acquisition was investigated. On each trial subjects estimated two positions on a linear-positioning apparatus. One group of subjects was presented two biasing movements, which they immediately recalled, during the KR-delay interval. The interpolated motor short-term memory task interfered with skill acquisition and retention.     

The Effect of Time-Compressed Speech on Comprehensive,Interpretive, and Short-Term Listening

Although contemporary theorists view listening as a multidimensional process, the preponderance of published empirical research on human comprehension of speeded speech is based on an outdated, unitary construct. In the present study, the impact of varying levels of time compression on three different types of listening is investigated. The results indicate that comprehensive listening performance deteriorates significantly as speech compression levels are increased while interpretive and short-term listening performance remains stable until a high degree of time compression (60%) is reached. Explanations for these findings are advanced based upon established differences between short and long-term memory processes.     

The Effect of Interpolated Motor Activity on the Short-Term Retention of Movement Distance and End-Location

The effect of an interpolated movement on the recall of a blind, lever-positioning movement was assessed separately for the reproduction cues of distance and end-location. Both cues showed the context effect of assimilation, that is, the end-location of the interpolated movement caused directional biasing of the algebraic or constant error (CE) for location reproduction while the length of the interpolated movement caused similar directional biasing for distance reproduction. Variability about algebraic error (VE) was used to assess forgetting. There was no change in VE for location reproduction, and an increase in VE for distance reproduction was limited to the relatively large movements. Thus, an interpolated movement that does not have to be remembered does not cause interference with the retention of location information, but does cause some interference with the retention of distance information. The findings are discussed in relation to a model of motor short-term memory which incorporates both CE and VE.     

The Effects of Time and Distance on Accuracy of Target-Directed Locomotion

Dual adaptation to different amounts or directions of prismatic displacement, or both, can be acquired and maintained with little mutual interference. Associative recalibration of the regional task- or workspace, contingent on differentiation of distinguishing sensory information, can explain such adaptation. In contrast, nonassociative realignment restores dimensional mapping among spatial representations. Methods for measuring the separate contributions of those 2 kinds of prism adaptation are identified in the present article. On the basis of a critique of dual-adaptation studies, the authors suggest that recalibration can explain the data but that the method used in those experiments confounded realignment and might have obscured the effectiveness of dual-calibration training.     

Effect of pressure on the mechanical and dynamical stability of NaAlSi

The effects of pressure on the mechanical and dynamical stability of NaAlSi have been fully investigated by first-principles calculations within the generalised gradient approximation (GGA). The obtained results show that the optimised lattice constants, atomic positions and elastic constants at ambient pressure are in good agreement with the available experimental and theoretical data. The lattice constants decrease monotonically with increasing pressure. The elastic constant C₁₁, C₁₂, C₁₃, C₃₃ and C₆₆ increase while C₄₄ decreases with increasing pressure. It is found that NaAlSi is mechanically unstable when the pressure is above 25.97?GPa. The phonon-dispersion curves along several high symmetry lines are obtained. The phonon frequencies at the Z point decrease with increasing pressure and completely soften to zero at 27.52?GPa, further confirming the structural instability of NaAlSi.     

The Effect of Attentional Control and Heart-Period Variability on Negative Affect and Trait Anxiety

In this study, the author examines the effect of attentional control and heart-period variability on measures of negative affect and trait anxiety in undergraduate students. Baseline heart rate was recorded from 119 participants within a laboratory setting. Spectral analysis was used on the heart-rate data to isolate the parasympathetic contribution to the cardiac pattern. Participants completed measures of negative affect, attentional control, and trait anxiety following the recording of heart rate. Regression analysis indicated that high negative affect, low attentional control, and reduced parasympathetic tone were significant predictors of high trait anxiety. Subsequent regression analysis pointed toward the interaction of attentional control and parasympathetic tone in influencing self-rated measures of negative affect. Results highlight the importance of attentional control and parasympathetic tone as regulatory mechanisms related to self-rated estimates of negative affect and trait anxiety.     

识解水平对跨期选择和风险选择的影响

通过考察识解水平启动对跨期选择和风险选择的影响, 探究两类选择对时间或风险心理加工的相似性。结果发现, 无论以思维诱导为识解水平的启动条件(实验1), 还是以视觉加工为识解水平的启动条件(实验2), 受高识解水平启动的被试对延迟选项和风险选项的主观值判断都要大于受低识解水平启动的被试, 说明跨期选择中的延迟时间和风险选择中的概率具有相似的表征, 而识解水平思维定势是通过影响金额和时间(或概率)的相对权重起作用。即由于高识解水平下的金额权重高于低识解水平, 时间(或概率)权重低于低识解水平, 从而使被试在高识解水平下更愿意等待或冒险。     

权力感和任务难度对个体建议采纳的影响

从人际关系的视角,通过两个实验探讨权力感和任务难度对个体建议采纳的影响。实验一启动被试的合理权力感,实验二启动被试的不合理权力感。研究发现：(1)当权力合理时,权力感水平对建议采纳有显著影响,高权力感水平决策者的建议采纳程度显著低于低权力感水平的决策者;任务难度对建议采纳有显著影响,决策者在困难任务中的建议采纳程度显著高于简单任务中。(2)当权力不合理时,在简单任务中,高权力感水平决策者的建议采纳程度显著低于低权力感水平的决策者;而在困难任务中,两者的建议采纳程度没有显著性差异。     

韩-汉跨语言词义水平的重复知盲效应*

关于语义水平的重复知盲效应一直存在争论。本研究考察非平衡韩-汉双语者在语言内和语言间词义水平的RB效应。实验1采用韩语双字词为实验材料探究韩语语言内的RB效应,结果表明在韩语词汇水平存在RB效应。实验2采用两个关键词为韩语（R1）和汉语（R2）双字词,并通过韩-汉语间隔词W的语言类型变化探究韩、汉语言间的RB效应,结果表明：不同语言类型的间隔词的正确率有显著差异,语义重复词R2在重复条件的正确率显著高于非重复条件,出现语义重复启动效应。本研究结论是：（1）在韩语语言内词水平存在RB效应,具有语言类型普遍性;（2）韩、汉跨语言语义水平出现语义重复启动效应,而未发生RB效应,表明双语者在加工韩、汉两种语言时,采用分别形式表征和共享语义表征的方式。