The Timing Effects of Accent Production in Periodic Finger-Tapping Sequences

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.     

Resistance To Change As A Function Of Stimulus-reinforcer And Location-reinforcer Contingencies

Pigeons responded on two keys in each component of a multiple concurrent schedule. In one series of conditions the distribution of reinforcers between keys within one component was varied so as to produce changes in ratios of reinforcer totals for key locations when summed across components. In a second series, reinforcer allocation between components was varied so as to produce changes in ratios of reinforcer totals for components, summed across key locations. In each condition, resistance to change was assessed by presenting response-independent reinforcers during intercomponent blackouts and (for the first series) by extinction of responding on both keys in both components. Resistance to change for response totals within a component was always greater for the component with the larger total reinforcer rate. However, resistance to change for response totals at a key location was not a positive function of total reinforcement for pecking that key; indeed, relative resistance to extinction for the two locations showed a weak negative relation to ratios of reinforcer totals for key location. These results confirm the determination of resistance to change by stimulus—reinforcer contingencies.     

思维定势浅议

思维定势是指人们在思维过程中自觉或不自觉地形成的一种比较稳定的思维趋向．由于思维的惯性作用,人们往往频向于以原有的知识和经验去对待和衡量新的信息．思维定势的形成,主要是由一子思维的参照系数大小,思维主体长期接受同一信息的频繁刺激而造成的．思维定势在思维过程中有积极的一面,当思维主体原有的知识和经验与新信息相一致时,主体凭经验即可对事物作出正确的判断．但是当思维主体原有的知识和经验与新信息发生矛盾时,思维定势便呈现出消极影响。在这种情况下,由于思维主体总是趋向于用老经验老方法去解释新信息,而不愿意…     

创意就是财富

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爱的逻辑

爱的逻辑常常不合逻辑,它总是拿规范意义上的逻辑开涮。例如,规范意义上的“打”与“骂”总是恶煞煞的．可民间却偏偏有一句描写爱情的话叫“打是亲骂是爱”,自然,仅此一句,也就道出了爱的逻辑的博大精深．那么．爱的逻辑何样？爱的逻辑玄奥无比：冬天和心爱的人在一起,你会不觉得冷！夏天和心爱的人在一起。你会不觉得热！“把你架在火上烤三分钟,您会觉得象烤了三年,可让你在心上人旁边坐三年,你会觉得才坐了三分钟！”爱的逻辑喜欢“自相矛盾”：陪你逛街的那个女孩子其实早就累了,可她却偏偏笑眯眯地问：“你累了吗？”爱你的…     

辩证思维

辩证思维区分为朴素辩证思维与理性辩证思维。朴素辩证思维是人们按照世界运动、发展和变化的本来面貌如实地反映世界,是自发地对自然界中到处存在的对立统一运动的反映,即人们未自觉掌提辩证法之前所进行的辩证思维,正像人们远在散文这一名词出现以前,就已经在用散文说话一样．理性辩证思维是人们自觉运用辩证法观点,接照辩证法的基本要求所进行的思维。这种思维是一种主观辩证法,是对客观辩证法的自觉运用．因此,只有精通并自觉运用辩证法的人,才能有理性辩证思维．同形而上学思维相比,理性辩证思维有下述四个特征：（1）全面性…     

能力──竞争实力的核心

现代社会是市场经济的社会。经济、政治、文化等各个领域,都充满着竞争的搏击。任何人参加竞争,既要靠客观条件,如拥有资本、历史机遇等等;又要靠主观条件,如知识丰富、聪明睿等等．靠什么具备这些条件？人的能力．拥有资本靠人的能力创造,历史机遇靠人的能力抓住,知识丰富靠人的能力获得,聪明睿智靠人的能力炼成。竞争实力来自竞争能力．人们总是度稳量力,凭借能力,参加竞争。竞争关系就是能力关系：能力强,竞争胜;能力弱,竞争败。竞争的能力从哪里来？我们自然会想到“知识就是力量”的名言。然而,知识并不等于能力。有的人…