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1.
It has been claimed that rhythmic tapping and circle drawing represent fundamentally different timing processes (event-based and emergent, respectively) and also that circle drawing is difficult to synchronize with a metronome and exhibits little phase correction. In the present study, musically trained participants tapped with their left hands, drew circles with their right (dominant) hands, and also performed both tasks simultaneously. In Experiment 1, they synchronized with a metronome and then continued on their own, whereas in Experiment 2, they synchronized with a metronome containing phase perturbations. Circle drawing generally exhibited reliable synchronization, although with greater variability than tapping, and also showed a clear phase-correction response that evolved gradually during the cycle immediately following a perturbation. When carried out simultaneously in synchrony, with or without a metronome, the two tasks affected each other in some ways but retained their distinctive timing characteristics. This shows that event-based and emergent timing can coexist in a dual-task situation. Furthermore, the authors argue that the two timing modes usually coexist in each individual task, although one mode is often dominant.  相似文献   

2.
Synchronization of finger taps with an isochronous event sequence becomes difficult when the event rate exceeds a certain limit. In Experiment 1, the synchronization threshold was reached at interonset intervals (IOIs) above 100 ms with auditory tone sequences (in a 1:4 tapping task) but at IOIs above 400 ms with visual flash sequences (1:1 tapping). Using IOIs above those limits, the author investigated in Experiment 2 the reduction in the variability of asynchronies that tends to occur when the intervals between target events are subdivided by additional identical events (1:1 vs 1:n tapping). The subdivision benefit was found to decrease with IOI duration and to turn into a cost at IOIs of 200–250 ms in auditory sequences and at IOIs of 450–500 ms in visual sequences. The auditory results are relevant to the limits of metrical subdivision and beat rate in music. The visual results demonstrate the remarkably weak rhythmicity of (nonmoving) visual stimuli.  相似文献   

3.
In models of sensorimotor synchronization, it is generally assumed that phase correction occurs in response to information about sensorimotor asynchrony or relative phase. Without such feedback, a phase perturbation in the motor activity should not be followed by phase correction. Alternatively, internally generated temporal expectations could provide a basis for phase correction in the absence of feedback. To test those hypotheses, the author conducted an experiment in which participants (N = 8) tapped their finger in synchrony with isochronous auditory sequences containing a single shifted event onset, after which there could be a gap of up to 3 missing events. Participants were instructed to not react to the shifted event and to continue tapping regularly during any gap. The shifted event caused an involuntary phase shift of the following tap. The shift was corrected if the sequence continued, but during a gap, the shift persisted without correction. Those results confirm that sensory feedback is necessary for phase correction to occur.  相似文献   

4.
Muscular output was measured in terms of strength, endurance, impulse, and recovery, with 10 Ss, 4 times per day over 15 successive days. A general index (the mean percentage of baseline performance with all measures) indicated that performance generally improved over the first 5 or 6 days, and remained relatively stable thereafter. The measures of strength were sensitive to within-day effects, whereas endurance and recovery measures were not influenced by such circadian rhythms.  相似文献   

5.
Recent work provides clues that different cortical mechanisms may be employed when correcting for errors in sensorimotor synchronization that increase tap-tone asynchrony compared with those that decrease it. The authors tested this hypothesis by recording 64-channel electroencephalography while participants synchronized with an auditory metronome. We systematically introduced positive and negative phase-shift perturbations that were either liminal (10%) and subliminal (3%). We used a distributed source modeling approach to evaluate oscillatory activity and connectivity of discrete cortical sources. Three key findings support our hypothesis. First was a theta band response indicative of error detection and top-down control observed in frontomedial presupplementary motor area (pre-SMA) and anterior cingulate for liminal positive perturbations. Second was an increase in theta band coupling between the SMA and contralateral motor cortex exclusively for positive perturbations suggesting a top-down modulation of motor parameters. Third, when compared with other conditions, liminal positive perturbations result in an increase in postmovement beta rebound within contralateral primary motor cortex. The authors propose that frontomedial motor areas exert a top-down inhibitory influence over the primary motor cortex to effectively lengthen tap intervals in response to lengthening tap-tone asynchronies.  相似文献   

6.
When subjects are required to produce short sequences of equally paced finger taps and to accentuate one of the taps, the interval preceding the forceful tap is shortened and the one that immediately follows the accent is lengthened. Assuming that the tapping movements are triggered by an internal clock, one explanation attributes the mistiming of the taps to central factors: The momentary rate of the clock is accelerated or decelerated as a function of motor preparation to, respectively, increase or decrease the movement force. This hypothesis predicts that the interre-sponse intervals measured between either tap movement onsets or movement terminations (taps) will show the same timing pattern. A second explanation for the observed interval effects is that the tapping movements are triggered by a regular internal clock but the timing of the successive taps is altered because the forceful movement is completed in less time than the other tap movements are. This “peripheral” hypothesis predicts regular timing of movement onsets but distorted timing of movement terminations. In the present study, the trajectories of the movements performed by subjects were recorded and the interresponse intervals were measured at the beginning and the end of the tapping movements. The results of Experiment 1 showed that neither model can fully explain the interval effects: The fast forceful movements were initiated with an additional delay that took into account the small execution time of these movements. Experiment 2 reproduced this finding and showed that the timing of the onset and contact intervals did not evolve with the repetition of trial blocks. Therefore, the assumption of an internal clock that would trigger the successive movements must be rejected. The results are discussed in the framework of a modified two-stage model in which the internal clock, instead of triggering the tapping movements, provides target time points at which the movements have to produce their meaningful effects, that is, contacts with the response key. The timing distortions are likely to reflect both peripheral and central components.  相似文献   

7.
发展性阅读障碍是指个体在智力正常并且不缺乏学校教育的情况下, 仍无法获得与年龄相匹配的阅读技能的一种学习障碍, 其缺陷的本质一直是研究者争论的焦点。大量研究显示, 阅读障碍者常表现出听觉时间加工损伤。在行为层面, 阅读障碍者难以辨别快速、连续呈现刺激的顺序以及刺激本身的动态时间特征。在神经层面, 阅读障碍者诱发的失匹配负波更弱且具有异常的神经同步加工。这些损伤同时存在于对言语和非言语刺激的加工中, 表明听觉时间加工缺陷非言语加工所特有。未来的研究还需阐明以下几个问题:1)阅读障碍的听觉时间加工缺陷发生在哪些时间窗口, 随年龄增长如何变化; 2)阅读障碍听觉时间加工缺陷在神经层面的时间进程是怎样的; 3)听觉时间加工缺陷是否为阅读障碍的核心缺陷。  相似文献   

8.
Faking is a common problem in testing with self‐report personality tests, especially in high‐stakes situations. A possible way to correct for it is statistical control on the basis of social desirability scales. Two such scales were developed and applied in the present paper. It was stressed that the statistical models of faking need to be adapted to different properties of the personality scales, since such scales correlate with faking to different extents. In four empirical studies of self‐report personality tests, correction for faking was investigated. One of the studies was experimental, and asked participants to fake or to be honest. In the other studies, job or school applicants were investigated. It was found that the approach to correct for effects of faking in self‐report personality tests advocated in the paper removed a large share of the effects, about 90%. It was found in one study that faking varied as a function of degree of how important the consequences of test results could be expected to be, more high‐stakes situations being associated with more faking. The latter finding is incompatible with the claim that social desirability scales measure a general personality trait. It is concluded that faking can be measured and that correction for faking, based on such measures, can be expected to remove about 90% of its effects.  相似文献   

9.
The authors investigated the relation between hand kinematics and eye movements in 2 variants of a rhythmical Fitts's task in which eye movements were necessary or not necessary. P. M. Fitts's (1954) law held in both conditions with similar slope and marginal differences in hand-kinematic patterns and movement continuity. Movement continuity and eye—hand synchronization were more directly related to movement time than to task index of difficulty. When movement time was decreased to fewer than 350 ms, eye—hand synchronization switched from continuous monitoring to intermittent control. The 1:1 frequency ratio with stable π/6 relative phase changed for 1:3 and 1:5 frequency ratios with less stable phase relations. The authors conclude that eye and hand movements in a rhythmical Fitts's task are dynamically synchronized to produce the best behavioral performance.  相似文献   

10.
Responding to patients' questions throughout the therapeutic process can be challenging. Questions posed at the beginning of treatment have unique features which make them especially difficult to negotiate. When handled skillfully and tactfully, questions asked during this phase can provide the therapist with important opportunities to foster engagement in treatment. Questions can provide valuable information about the patient's internal world, afford the opportunity to socialize the patient to the therapeutic process, and aid in rapport-building. This article will focus on ways to understand and handle questions patients ask during the initial phase of treatment. Vignettes will be presented and specific responses therapists can offer to patients will be discussed.  相似文献   

11.
Although the word‐frequency effect is one of the most established findings in spoken‐word recognition, the precise processing locus of this effect is still a topic of debate. In this study, we used event‐related potentials (ERPs) to track the time course of the word‐frequency effect. In addition, the neighborhood density effect, which is known to reflect mechanisms involved in word identification, was also examined. The ERP data showed a clear frequency effect as early as 350 ms from word onset on the P350, followed by a later effect at word offset on the late N400. A neighborhood density effect was also found at an early stage of spoken‐word processing on the PMN, and at word offset on the late N400. Overall, our ERP differences for word frequency suggest that frequency affects the core processes of word identification starting from the initial phase of lexical activation and including target word selection. They thus rule out any interpretation of the word frequency effect that is limited to a purely decisional locus after word identification has been completed.  相似文献   

12.
The ethical treatment of cancer patientsparticipating in clinical trials requiresthat patients are well-informed about thepotential benefits and risks associated withparticipation. When patients enrolled in phaseI clinical trials report that their chance ofbenefit is very high, this is often taken as evidence of a failure of the informed consent process. We argue, however, that some simple themes from the philosophy of language may make such a conclusion less certain. First, the patient may receive conflicting statements from multiple speakers about the expected outcome of the trial. Patients may be reporting the message they like best. Second, there is a potential problem of multivocality. Expressions of uncertainty of the frequency type(e.g., ``On average, 5 out of every 100 patientswill benefit') can be confused with expressionsof uncertainty of the belief type (e.g.,``The chance that I will benefit is about80%'). Patients may be informed using frequency-type statements and respond using belief-type statements. Third, each speech episode involving the investigator and the patient regarding outcomes may subservemultiple speech acts, some of which may beindirect. For example, a patient reporting ahigh expected benefit may be reporting a beliefabout the future, reassuring family members,and/or attempting to improve his or her outcome by apublic assertion of optimism. These sources oflinguistic confusion should be considered injudging whether the patient's reported expectation isgrounds for a bioethical concern that there hasbeen a failure in the informed consent process.  相似文献   

13.
研究采用经典的R/K范式,通过两个实验分别探讨编码阶段和检索阶段的异质情境流畅性对再认的影响。实验1为2(异质情境:高流畅性预期情境和低流畅性预期情境)×2(测试词类型:目标词和分心词)的混合实验设计,异质情境发生在编码阶段;实验2与实验1设计相同,不同之处在于异质情境发生在检索阶段。结果发现:异质情境发生在检索阶段时只对K反应产生影响,目标词在高流畅性情境中比低流畅性情境中的K反应率更高,而分心词在低流畅性情境中比高流畅性情境中的K反应率更高。研究表明,检索阶段的异质情境流畅性只影响熟悉性再认,支持双系统加工理论。  相似文献   

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