首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 19 毫秒
1.
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   

2.
Motor inhibition is considered to be an important process of executive control and to be implicated in numerous activities in order to cancel prepared actions and, supposedly, to suppress ongoing ones. Usually, it is evaluated using a “stop-signal task” in which participants have to inhibit prepared discrete movements. However, it is unknown whether other movement types involve the same inhibition process. We therefore investigated whether the inhibition process for discrete movements is involved in stopping ongoing rhythmic movements as well.Twenty healthy adults performed two counterbalanced tasks. The first task was used to estimate the stop-signal reaction time (SSRTd) needed to inhibit prepared discrete key-pressing movements. In the second task, participants drew graphic patterns on a tablet and had to stop the movement when a stop-signal occurred. We calculated the rhythmic stop signal-reaction time as the time needed to initiate stopping such ongoing rhythmic movement (SSRTr) and the same latency relative to the period of the rhythmic movement (relSSRTr). We measured these delays under different movement frequencies and motor coordination conditions and further investigated whether they varied as a function of several parameters of the rhythmic movements (speed, mean and variance of the relative phase, and movement phase at several time events).We found no correlation between inhibition measures in the two tasks. In contrast, generalized linear models showed a moderate yet significant influence of the motion parameters on the inhibition of ongoing rhythmic movements. We therefore conclude that the motor inhibition processes involved in cancelling prepared discrete movements and stopping ongoing rhythmic movements are dissimilar.  相似文献   

3.
《Acta psychologica》2013,143(3):310-316
Grasping movements are often planned in a way that they end in a position where joints are in an anatomically medial position. This behaviour is termed the “end-state comfort” (ESC) effect (Rosenbaum et al., 1990). We suggest that the anatomically medial position is favoured to control the most difficult part of the movement. In most experiments investigating ESC, objects have to be placed onto a target location, and the highest precision demand occurs at the end of the movement. Thus, ESC is confounded with movement difficulty. In this study, we dissociate movement difficulty and ESC. In our experiments, participants had to execute a task where the critical part of the movement was either at the end or at the beginning of the movement. Participants' grasping behaviour confirmed the hypothesis that movement planning is constrained by a goal for optimal control during the part of the movement that demands the highest precision, rather than by a goal to end in a comfortable state (Rosenbaum, Chapman, Weigelt, Weiss, & van der Wel, 2012). We identified recall and movement plan generating processes of motor planning (Cohen & Rosenbaum, 2004), that ensure the optimal control in the critical part of movement. Our results indicate that recall processes depend on motor experience which is acquired in different time scales. We suggest that motor planning processes are triggered only if the costs for executing movements controlled by recall processes exceed the costs for generating a motor plan.  相似文献   

4.
Tilsen S 《Cognitive Science》2009,33(5):839-879
Temporal patterns in human movement, and in speech in particular, occur on multiple timescales. Regularities in such patterns have been observed between speech gestures, which are relatively quick movements of articulators (e.g., tongue fronting and lip protrusion), and also between rhythmic units (e.g., syllables and metrical feet), which occur more slowly. Previous work has shown that patterns in both domains can be usefully modeled with oscillatory dynamical systems. To investigate how rhythmic and gestural domains interact, an experiment was conducted in which speakers performed a phrase repetition task, and gestural kinematics were recorded using electromagnetic articulometry. Variance in relative timing of gestural movements was correlated with variance in rhythmic timing, indicating that gestural and rhythmic systems interact in the process of planning and producing speech. A model of rhythmic and gestural planning oscillators with multifrequency coupling is presented, which can simulate the observed covariability between rhythmic and gestural timing.  相似文献   

5.
In the “Libet experiment” the onset of movement-related brain activity preceded the reported time of the conscious intention to move, suggesting that conscious intention may not play a role in initiating voluntary movements (Libet, Gleason, Wright, & Pearl, 1983). Dominik et al. (2017) provided evidence that the intention reports employed in the Libet experiment, which Libet et al. (1983) found to precede movement reports, are invalid. In the study by Dominik et al., intention reports preceded movement reports only when participants had prior experience making movement reports. Individuals without such experience reported intention around the same time as movement. These findings suggest that Libet’s intention reports do not reflect experiences of intention, but, rather, inferences based on prior experience with movement reports. Our study replicated the core findings of Dominik et al. We argue that Libet’s intention reports are invalid and explore the phenomenology of intention in the Libet experiment.  相似文献   

6.
In two experiments, Brookshire, Ivry, and Casasanto (2010) showed that words with positive and negative emotional valence can activate spatial representations with a high degree of automaticity, but also that this activation is highly context dependent. Lebois, Wilson‐Mendenhall, and Barsalou (2015) reported that they “aimed to replicate” our study but found only null results in the “Brookshire et al. replication” conditions. Here we express concerns about three aspects of this paper. First, the study was not an attempt to replicate ours; it was a different study that adapted our method. Second, Lebois et al. did not accurately represent our theoretical position. Third, Lebois et al.’s main conclusion, that spatial congruity effects depend on the task context, was not supported by their data. Despite these concerns, we agree with Lebois et al.'s overall message that spatial aspects of words' meanings are activated differently in different contexts. This was a main conclusion of our study as well.  相似文献   

7.
The intention to execute a movement can modulate our perception of sensory events, and this modulation is observed ahead of both ocular and upper limb movements. However, theoretical accounts of these effects, and also the empirical data, are often contradictory. Accounts of “active touch”, and the premotor theory of attention, have emphasized how movement intention leads to enhanced perceptual processing at the target of a movement, or on the to-be-moved effector. By contrast, recent theories of motor control emphasize how internal “forward” model (FM) estimates may be used to cancel or attenuate sensory signals that arise as a result of self-generated movements. We used behavioural and functional brain imaging (functional magnetic resonance imaging, fMRI) to investigate how perception of a somatosensory stimulus differed according to whether it was delivered to a hand that was about to execute a reaching movement or the alternative, nonmoving, hand. The results of our study demonstrate that a somatosensory stimulus delivered to a hand that is being prepared for movement is perceived to have occurred later than when that same stimulus is delivered to a nonmoving hand. This result indicates that it takes longer for a tactile stimulus to be detected when it is delivered to a moving limb and may correspond to a change in perceptual threshold. Our behavioural results are paralleled by the results of our fMRI study that demonstrated that there were significantly reduced blood-oxygen-level-dependent (BOLD) responses within the parietal operculum and insula following somatosensory stimulation of the hand being prepared for movement, compared to when an identical stimulus was delivered to a nonmoving hand. These findings are consistent with the prediction of FM accounts of motor control that postulate that central sensory suppression of somatosensation accompanies self-generated limb movements, and with previous reports indicating that effects of sensory suppression are observed in higher order somatosensory regions.  相似文献   

8.
Phase coupling between movement trajectories has been proposed as the basic mechanism of hand coordination in the production of bimanual rhythmic movements with a 1:2 frequency ratio. Here a central temporal coupling view is proposed as an alternative. Extending previous models of two-handed synchronic and alternate-hand tapping, we hypothesized that 1:2 tapping is performed under the control of a single internal timekeeper set at the frequency required for the fast hand. The fast hand is assumed to use every signal and the slow hand every other signal of the timekeeper, to produce actions coordinated in time. The model's predictions for the variance-covariance pattern of tap timing within and across hands were tested in an experiment that required tapping with both hands with 1:1 or 1:2 frequency ratio. The finger contact on the response plate was to be short or long, according to instruction. Prolonged finger contact entailed profound modifications in the movement trajectories but failed to modify the variance-covariance pattern of the tap timing. This pattern proved to conform to predictions under both the short and the long contact conditions, thus supporting the central temporal coupling hypothesis.  相似文献   

9.
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 rnistiming 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 interresponse 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   

10.
Reichle ED  Rayner K  Pollatsek A 《The Behavioral and brain sciences》2003,26(4):445-76; discussion 477-526
The E-Z Reader model (Reichle et al. 1998; 1999) provides a theoretical framework for understanding how word identification, visual processing, attention, and oculomotor control jointly determine when and where the eyes move during reading. In this article, we first review what is known about eye movements during reading. Then we provide an updated version of the model (E-Z Reader 7) and describe how it accounts for basic findings about eye movement control in reading. We then review several alternative models of eye movement control in reading, discussing both their core assumptions and their theoretical scope. On the basis of this discussion, we conclude that E-Z Reader provides the most comprehensive account of eye movement control during reading. Finally, we provide a brief overview of what is known about the neural systems that support the various components of reading, and suggest how the cognitive constructs of our model might map onto this neural architecture.  相似文献   

11.
Accurate timing of limb displacement is crucial for effective motor control. The authors examined the effects of movement velocity, duration, direction, added mass, and auditory cueing on timing, spatial, and trajectory variability of single- and multijoint rhythmic movements. During single-joint movements, increased velocity decreased timing and spatial variability, whereas increased movement duration increased timing variability but decreased spatial variability. For multijoint movements, regardless of condition, increasing velocity decreased joint timing, spatial, and trajectory variability, but all hand variabilities were unaffected by velocity, duration, load, or direction. Timing, spatial, and trajectory variability was greater at the shoulder compared with the elbow and minimal at the hand, supporting the notion that reaching movements are planned in hand space as opposed to joint space.  相似文献   

12.
The open-loop model by Wing and Kristofferson has successfully explained many aspects of movement timing. A later adaptation of the model assumes that timing processes do not control the movements themselves, but the sensory consequences of the movements. The present study tested direct predictions from this “sensory-goals model”. In two experiments, participants were instructed to produce regular intervals by tapping alternately with the index fingers of the left and the right hand. Auditory feedback tones from the taps of one hand were delayed. As a consequence, regular intervals between taps resulted in irregular intervals between feedback tones. Participants compensated for this auditory irregularity by changing their movement timing. Compensation effects increased with the magnitude of feedback delay (Experiment 1) and were also observed in a unimanual variant of the task (Experiment 2). The pattern of effects in alternating tapping suggests that compensation processes were anticipatory—that is, compensate for upcoming feedback delay rather than being reactions to delay. All experiments confirmed formal model predictions. Taken together, the findings corroborate the sensory-goals adaptation of the Wing–Kristofferson model.  相似文献   

13.
14.
《Human movement science》1986,5(3):275-296
Previous research into the handwriting of adult subjects has highlighted the possible roles of ‘relative timing’ (Viviani and Terzuolo 1980) and simple oscillations (Hollerbach 1981) in controlling movement. Both of these factors provide interesting perspectives with which to view the development of fine motor control in children. The spatio-temporal structure of writing movements was examined between children with refined handwriting skills and those exhibiting unusually poor writing for their age. The analysis concentrated on three sites of temporal variability: absolute timing, temporal patterning, and rhythmic content of the writing movements. The results supported the notion that the relative timing of segments within a movement sequence acts as a major constraint on motor output variability. It is suggested, however, that previous simplistic views of ‘relative timing’ be expanded, and that such timing may be dictated by optimisation strategies. Differences in the stability of the graphic product between groups could not be accounted for by differences in the rhythmic content of the movements. In the absolute timing of writing tasks, the results suggest that variability in writing time from trial to trial, and duration of intra-task pauses, are better indicators of writing difficulties than total writing time or the number of pauses.  相似文献   

15.
McNeill et al. (2020) recently published a study that first aimed to assess the effect of a combination of motor imagery (MI) and action observation (AO) on golf putt performance and then to determine if the evolution of this performance could be moderated by participants’ kinesthetic imagery ability. To assess golfers’ MI ability, the authors used the third version of the Movement Imagery Questionnaire. Participants notably self-estimated their kinesthetic MI ability by using a Likert-type scale, with scores ranging from 1 “very difficult to feel” to 7 “very easy to feel”. Athletes were categorized as either “poor” or “good” kinesthetic imagers, with mean scores of 4.93 and 6.63, respectively, in the intervention groups. Although a similar categorization procedure had previously been used in the literature for “good imagers”, the mean scores for “poor” imagers were much higher than those noted in previous studies evaluating the effect of MI ability on motor accuracy. Moreover, the low number of participants in the intervention group (n = 22) meant that participants were considered “poor” imagers even though their mean scores corresponded to “quite easy to feel” kinesthetic images of movements. This could notably explain the lack of differences between “poor” and “good” imagers in terms of putting performance in the intervention group. Despite these methodological limitations, the results of McNeill et al.‘s study show promising evidence for the efficacy of an AO plus MI intervention in relation to putting performance and should lead to further investigations. We suggest that research in the area of motor imagery ability include larger samples to explore, in individuals with very low imagery ability scores, the effects of the combination of AO and MI on motor performance.  相似文献   

16.
智慧与美德是独立但相互作用的心理结构。针对其关系,以往哲学家与心理学家基于个人经验和文化观念进行了大量规范性层面的理论思辨,但仍存在理论分歧(线性论、阈值论、从属论),且缺少以定量方法为主的描述性层面的实证研究,尤其缺乏基于实验的关于“智”与“仁”双向因果关系的探索。未来研究可以借鉴实验伦理学的范式,着眼于研究特定领域、特定情境下智慧与美德之间的双向因果关系,加强中国文化背景下的智慧与美德关系的研究,并探索其潜在的认知神经机制。如何统一智慧与美德关系的“应然”与“实然”的研究,是接下来需要面临的挑战。  相似文献   

17.
研究采用4(呈现方式:小-小、小-大、大-小、大-大)×2(文本内容:句子、“※”串)的被试内设计,考察了文本字符呈现大小对读者眼跳选择目标和注视持续时间的影响。结果发现:(1)读者在浏览不同呈现方式的“※”串时的眼动模式基本上与阅读相应呈现方式的句子类似;(2)句子完全是由双字词构成,词内的首字和尾字大小不等(‘小-大”和“大-小”呈现条件)严重影响阅读效率;(3)读者在阅读句子时的注视时间高于浏览“※”串时的注视时间。结果说明,视觉呈现方式和词汇加工均影响读者的眼动模式。  相似文献   

18.
The “hybrid” model of object recognition (Hummel, 2001) proposes that unattended objects are processed holistically, while attended objects are processed both holistically and analytically. Supporting evidence for this claim was reported by Thoma, Hummel, and Davidoff (2004) who showed that, unlike whole object primes, unattended split object parts (presumed to require analytic processing) do not elicit repetition priming. Here we tested the generality of this finding by contrasting priming for whole and part prime stimuli as a function of prime informativeness and by modifying the design so that both unattended whole and part prime displays contained a single perceptual object. Unlike Thoma et al. (2004) the results showed negative (rather than an absence of) priming for unattended half object primes. These findings place new constraints on theoretical models of the role of attention in object recognition.  相似文献   

19.
通过两个实验对中国学者提出的“推理题与推理者的推理知识双重结构模型”和Evans提出的“双重加工理论”进行了实验比较研究。实验一通过两种评定方法对相应性质命题进行评定后所得实验结果表明Evans等(1983)有关“信念效应”研究中的“结论可信性”变量可以视为与胡竹菁等(1996)实验中的“内容正确性”变量是同一性质的变量; 实验二根据“形式正确性”和“内容正确性”两个自变量设计的推理实验结果与Evans等(1983)的研究结果基本一致; 但增加“内容熟悉性”这一自变量设计的推理实验结果表明“推理题与推理者的推理知识双重结构模型”比Evans提出的“双重加工理论”能更好地解释推理者对性质三段论的推理结果。  相似文献   

20.
Based on a model developed by Kunnen et al. (in: Nurmi (ed) Navigating through adolescence: European perspectives, 2001), we investigated trajectories of commitment development in university students and their relation with well-being, identity style, coping, personality, and ego-development. By means of cluster analysis on individual trajectories, we distinguished different clusters of trajectories in six domains of life. Almost all clusters could be classified according to the identity status theory, either on a moratorium-achieved trajectory (MAMA), or as a stable trajectory in one of the four identity statuses. As expected, clusters with stable strong commitment had highest levels of well-being, and MAMA clusters had highest levels of ego-development. In general, the condition “having no commitments for a prolonged period” was more strongly related to non-optimal outcomes than the condition “no exploration.” This is surprising, given the important role of exploration in identity development. We suggested that having no commitments may affect—probably temporarily—the coping preferences and personality characteristics. Differences between the domains can be interpreted as effects of different societal demands and the social or non-social nature of the domain.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号