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1.
    
The effect of three months of aerobic training on spatio-temporal and coordination parameters was examined during a swim trial at maximal aerobic speed. Nine male swimmers swam a 400-m front crawl at maximal speed twice: in trial 1, after summer break, and trial 2, after three months of aerobic training. Video analysis determined the stroke (swimming speed, stroke length, and stroke rate) and coordination (Index of Coordination and propulsive phase duration) parameters for every 50-m segment. All swimmers significantly increased their swimming speed after training. For all swimmers except one, stroke length increased and stroke rate remained constant, whereas the Index of Coordination and the propulsive phase duration decreased (p < .05). This study suggests that aerobic training developed a greater force impulse in the swimmers during the propulsive phases, which allowed them to take advantage of longer non-propulsive phases. In this case, catch-up coordination, if associated with greater stroke length, can be an efficient coordination mode that reflects optimal drag/propulsion adaptation. This finding thus provides new insight into swimmers’ adaptations to the middle-distance event.  相似文献   

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ObjectivesIn the psychology of sport and exercise, the question of how perfectionism affects performance is highly debated. While some researchers have identified perfectionism as a hallmark quality of elite athletes, others see perfectionism as a maladaptive characteristic that undermines, rather than helps, athletic performance. Against this background, the purpose of the present study was to investigate how different aspects of perfectionism predict performance and performance increments.MethodA study was conducted with 122 undergraduate athletes to investigate how perfectionism during training affects performance and performance increments in a series of trials with a new basketball training task. Two aspects of perfectionism were examined: striving for perfection and negative reactions to imperfection.DesignThe design was a correlational prospective design.ResultsResults showed that striving for perfection during training predicted higher performance in the new task. In contrast, negative reactions to imperfection predicted lower performance when athletes attempted the task for the first time, once the positive influence of striving for perfection on task performance was partialled out. However, negative reactions to imperfection did not undermine performance in the consecutive trials. On the contrary, athletes with both high levels of striving for perfection and high levels of negative reactions to imperfection showed the greatest performance increments over the series of trials.ConclusionThe findings suggest that perfectionism is not necessarily a maladaptive characteristic that generally undermines sport performance. Instead, when learning a new training task, perfectionism may enhance performance and lead to performance increments over repeated trials.  相似文献   

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Purpose  We isolate and describe four key elements that distinguish different forms of forced distribution systems (FDS). These key elements are the consequences for low performers, differentiation of rewards for top performers, frequency of feedback, and comparison group size. We examine how these elements influence respondents’ attraction to FDS. Design/methodology/approach  Undergraduate students (n = 163) completed a policy capturing study designed to determine how these four FDS elements influence their attraction to FDS. We examine the relative importance of these elements that most influence attraction to different FDS, as well as individual attributes (i.e., cognitive ability, gender, and major) that may affect those preferences. Findings  Respondents were most attracted to systems with less stringent treatment of low performers, high differentiation of rewards, frequent feedback and large comparison groups. Consequences for low performers were nearly twice as influential as any other element. Respondents with higher cognitive ability favored high reward differentiation and males were less affected by stringent consequences for low performers. Implications  Before practitioners implement FDS, it would be prudent to consider all four elements examined in this study—with the treatment of low performers being the most salient issue. Future accounts of FDS should clarify the nature of these elements when reporting on FDS. Such precision will be useful in generating a knowledge base on FDS. Originality/value   We add precision to the discussion of FDS by identifying four key elements. This is one of the first studies to examine perceptions of FDS from a ratee perspective.
Robert S. RubinEmail:
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5.
Much is known about the attractiveness of physical attributes, such as symmetry and averageness. Here we examine the effect of a social cue, eye-gaze direction, on facial attractiveness. Given that direct gaze signals social engagement, we predicted that faces showing direct gaze would be preferred to faces showing averted gaze. Thirty-two males completed two tasks designed to assess preferences for female faces displaying a neutral expression. Participants were more likely to select the face with direct gaze, when choosing the more attractive face from direct- and averted-gaze versions of the same face. This direct-gaze preference was stronger for high-attractive than low-attractive face sets, but was present for both. Attractiveness ratings were also higher for faces with direct than averted gaze. Interestingly, stimulus inversion weakened the preference for inverted faces, which suggests the preference does not simply reflect a bilateral symmetry bias.  相似文献   

6.
For receiver operating characteristic curves to be symmetric the signal distribution must be an orientation-reversing involution of the noise distribution on the strength axis.  相似文献   

7.
It is a widely held assumption that social cognition is wholly the result of natural selection and learning, debates arising over how much was naturally selected versus how much is learned. I argue here, however, for there being a third factor, namely physics, specifically symmetries and symmetry breakings in neural dynamics. These symmetries manifest themselves in social judgments in a fairly direct way as descending chains of subgroup types in mental social schemata. These schemata are the four models of Alan Page Fiske's relational-models typology. Descending chains of subgroup types are a phenomenon widely observed in nature; their presence in social cognition is consistent with there being a relevant neural network, the activity of which can undergo symmetry breakings. This would be analogous to the neural activity that has been computer modeled in an attempt to explain animal locomotion. This should encourage work towards specifying the particular symmetry groups in social cognition as a step towards devising computer models of the relevant neural mechanism. Approaches to animal locomotion suggest at least the broad outlines of how to proceed. Evidence of symmetry groups in social schemata also supports the view that the innate aspects of social cognition are at least partly structured by dynamics without being encoded in genes, just as the shape of the protective shell of some viruses results from dynamics without being genetically encoded.  相似文献   

8.
张璇  伍麟 《心理科学》2013,36(6):1333-1338
上世纪90年代研究者开始研究信任的“不对称性原则”,即失去信任比得到信任容易。十余年来,不同研究者从信息类型、灾害类型以及先前态度等方面对信任的“不对称性原则”展开了继续探索,认为信任的“不对称性原则”是有条件的。另有一部分研究者直接从信任的结构对“不对称性原则”进行了反驳,认为信任应该包括社会信任和信心,社会信任基于共享的价值观,是对称的;信心基于客观的行为标准,是不对称的。信任研究应该针对社会信任这一维度。之所以会出现“不对称”或“对称”的矛盾,主要是由于信任结构的不一致。前者将信任看成是一维的,而后者认为信任是二维的。这就推动了信任的理论结构探索和启发式研究。通过对信任机制的研究,风险管理者和专家能够在实际的风险管理中制定相应的提高公众信任的措施,推动科技发展,提高生活质量,提升风险管理。  相似文献   

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Previous studies suggest that functional ankle instability (FAI) may be associated with deficits in the ability to sense muscle forces. We tested individuals with FAI to determine if they have reduced ability to control ankle muscle forces, which is a function of force sense. Our test was performed isometrically to minimize the involvement of joint position sense and kinesthesia. A FAI group and a control group were recruited to perform an ankle force control task using a platform-based ankle robot. They were asked to move a cursor to hit 24 targets as accurately and as fast as possible in a virtual maze. The cursor movement was based on the direction and magnitude of the forces applied to the robot. Participants underwent three conditions: pre-test (baseline), practice (skill acquisition), and post-test (post skill acquisition). The force control ability was quantified based on the accuracy performance during the task. The accuracy performance was negatively associated with the collision count of the cursor with the maze wall. The FAI group showed reduced ability to control ankle muscle forces compared to the control group in the pre-test condition, but the difference became non-significant in the post-test condition after practice. The change in performance before and after practice may be due to different degrees of reliance on force sense.  相似文献   

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No abstract available for this article.  相似文献   

11.
Excessive television watching among children can have several negative consequences, including exposure to frequent violent and aggressive scenes and limitations in their opportunities to engage in alternative educational and prosocial activities. In the present study, a youngster evidencing high levels of television viewing behavior was placed on a modified token economy: earned tokens were used to activate the television for set periods of time. With onset of the intervention, immediate and dramatic reductions in television viewing were noted. High levels returned during a return to baseline phase, but reductions again occured when the intervention was reimplmented. Positive second-order effects were noted in the child's school work, in the amounts of time the family spent together, and in the mother's perception of a social support variable.  相似文献   

12.
It is shown that the symmetry of the receiver operating characteristic curve implies that the Kullback–Leibler divergences between the signal and noise populations are equal when the arguments are interchanged.  相似文献   

13.
Abstract

Photographic activity schedules were used to increase on-task behaviour in a youth with autism. The multiple probe design included baseline, training, tests for training effects, resequencing of photographs, generalization to new photographs, and maintenance. The results showed that the participant was able to carry out four different chains (photographic activity schedules) without any prompts from the staff, even when the photographs were resequenced, and new photographs were included. On the other hand, there was no reduction of training trials to reach criterion from the first to the fourth chain. The results are discussed with reference to different aspects of generalization.  相似文献   

14.
    
Our research explores connections between a fundamental element of visual design, namely symmetry, and consumer inferences regarding brand personality. In contrast to prior work focused on broad affective responses, we propose that symmetry plays an additional, nuanced role in the communication of brand personality. Results of four experiments reveal that asymmetry in visual brand elements is associated by consumers with brand excitement, and that the effect is driven in part by the experience of subjective arousal. These findings contribute to growing interest in visual design and consumer processing, while extending current understanding regarding the communication of brand personality.  相似文献   

15.
Cognitive-behavioral models of body dysmorphic disorder (BDD) propose that individuals with BDD may possess a better or more developed sense of aestheticality than do individuals without BDD. Evidence for this proposition, however, is limited. One perceptual process that could contribute to heightened aestheticality is the ability to detect differences in symmetry. In this experiment we tested whether individuals with BDD (n = 20), relative to individuals with obsessive compulsive disorder (OCD; n = 20) and healthy controls (n = 20), show an enhanced ability to detect differences in the symmetry of others’ faces, symmetry of dot arrays, and/or show a greater preference for symmetrical faces. Individuals with BDD were not significantly more accurate in detecting differences in facial symmetry or dot arrays relative to individuals with OCD and healthy controls. Individuals with OCD took longer to make facial symmetry judgments than did individuals in the other two groups. All participants, regardless of diagnostic group, preferred more symmetrical faces than nonsymmetrical ones. Taken together, our results do not support a heightened perceptual ability or evaluative preference for symmetry among individuals with BDD.  相似文献   

16.
Dry MJ 《Acta psychologica》2008,128(1):75-90
Numerous models of symmetry perception have been proposed in recent years. Unfortunately, it is difficult to assess the relative utility of these models as little effort has been made to directly compare them. This paper outlines a new model of symmetry perception based upon the relational structure revealed by Voronoi tessellation. The model has been developed in response to evidence suggesting that the human visual system is generating a Voronoi-like representation at an early stage in processing. Bayesian model selection is employed to compare the performance of the Voronoi model to that of five previously published models across six empirical datasets. The results indicate that the Voronoi model provides a more likely account of the data than the five alternative models.  相似文献   

17.
绩效评价的若干问题   总被引:7,自引:0,他引:7  
通过对绩效的内涵、绩效评价标准的确定、评量指标体系的构建以及多样性评量指标的整合意义与方法等四个绩效评价的最基本问题进行反思 ,提出如下观点 :(1 )对绩效进行考量时必须同时考虑时间、方式和结果三个维度。 (2 )绩效评价标准的确定应先于具体评量指标的选择 ,且应保持一定的稳定性 ,不可随意增删 ;(3 )评量指标体系的构建应本着贵精不贵多、贵明确不贵模糊、贵敏感不贵迟钝 ,贵关键不贵空泛的原则进行 ;(4)多样性评量指标是否整合需根据具体的需要而定 ,整合时要考虑评量指标本身的权重差异以及不同评价者由于对标准尺度掌握的松紧不一和评判角度不同所带来的对最终评价结果的影响。  相似文献   

18.
    
A major characteristic of hemiplegic gait observed in individuals post-stroke is spatial and temporal asymmetry, which may increase energy expenditure and the risk of falls. The purpose of this study was to examine the effects of swing resistance/assistance applied to the affected leg on gait symmetry in individuals post-stroke. We recruited 10 subjects with chronic stroke who demonstrated a shorter step length with their affected leg in comparison to the non-affected leg during walking. They participated in two test sessions for swing resistance and swing assistance, respectively. During the adaptation period, subjects counteracted the step length deviation caused by the applied swing resistance force, resulting in an aftereffect consisting of improved step length symmetry during the post-adaptation period. In contrast, subjects did not counteract step length deviation caused by swing assistance during adaptation period and produced no aftereffect during the post-adaptation period. Locomotor training with swing resistance applied to the affected leg may improve step length symmetry through error-based learning. Swing assistance reduces errors in step length during stepping; however, it is unclear whether this approach would improve step length symmetry. Results from this study may be used to develop training paradigms for improving gait symmetry of stroke survivors.  相似文献   

19.
    
In sign languages, the task of communicating a shape involves drawing in the air with one moving hand (Method One) or two (Method Two). Since the movement path is iconic, method choice might be based on the shape. In the present studies we aimed to determine whether geometric properties motivate method choice. In a study of 17 deaf signers from six countries, the strongest predictors of method choice were whether the shape has any curved edges (Method One), and whether the shape is symmetrical across the Y‐axis (Method Two), where the default was Method One. In a second study of ASL dictionary entries for which the movement path of the sign is iconic of an entity's shape, the same predictors surfaced. These tendencies are captured in the Lexical Drawing Principle, which is coherent with biological constraints on movement in general. Drawing in the air with two hands, however, is costly, both cognitively and biomechanically. Furthermore, it distinguishes signers from non‐signers, who draw shapes with only one hand. Signers assume this extra cost in the lexicon because of the enhanced iconicity the possibility of two hands offers; they assume it in drawing shapes in the air because they apply the same linguistic principle they use in the lexicon. Additionally, having a choice of methods allows the signer to benefit from over‐specification in providing redundant information about the shape, enhancing comprehensibility and resolving ambiguity.  相似文献   

20.
The effect of prism adaptation on movement is typically reduced when the movement at test (prisms off) differs on some dimension from the movement at training (prisms on). Some adaptation is latent, however, and only revealed through further testing in which the movement at training is fully reinstated. Applying a nonlinear attractor dynamic model (Frank, Blau, & Turvey, 2009) to available data (Blau, Stephen, Carello, & Turvey, 2009), we provide evidence for a causal link between the latent (or secondary) aftereffect and an additive force term that is known to account for symmetry breaking. The evidence is discussed in respect to the hypothesis that recalibration aftereffects reflect memory principles (encoding specificity, transfer-appropriate processing) oriented to time-translation invariance-when later testing conserves the conditions of earlier training. Forgetting or reduced adaptation effects follow from the loss of this invariance and are reversed by its reinstatement.  相似文献   

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