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.     

Influence of the initial projection of the centre of gravity on posturo-kinetic coordination in humans. Application from a horizontal quadrupedal stance during voluntary limb raising

The purpose of the study is to investigate the influence of initial projection of the centre of gravity (CG) on the spatial and temporal organization of the dynamic phenomena accompanying a voluntary movement in humans. From a horizontal quadrupedal stance, ten normal subjects were instructed to raise the right forelimb towards a support target in self paced velocity conditions. Three experimental conditions were tested for which the initial CG projection was either within (C1), at the limits of (C2) or outside the supporting triangle (C3). The results showed that vertical force variations on the four supports always preceded the first vertical displacement of the right wrist (onset of the movement). From C1 to C3, the duration of these anticipatory dynamic phenomena increased enabling an adjustment of the CG position such that equilibrium constraints were fulfilled. For all conditions, the acceleration peak of the CG occurred prior to the onset of movement and from C1 to C3, its magnitude increased in a single direction of the horizontal plane. For each condition, the load transfer was directed to the left forelimb and the right hindlimb (diagonal strategy) and reached a maximal value at the time of lift-off. With respect to this moment, the onset of the movement occurred increasingly early from C1 to C3. These results suggest that contribution of peripheral cues to postural control is more important, when the requirements of horizontal CG displacement increase.     

Professional ethics of psychologists and physicians: morality, confidentiality, and sexuality in Israel

Clinical psychologists' and nonpsychiatric physicians' attitudes and behaviors in sexual and confidentiality boundary violations were examined. The 171 participants' responses were analyzed by profession, sex, and status (student, resident, professional) on semantic differential, boundary violation vignettes, and a version of Pope, Tabachnick, and Keith-Spiegel's (1987) ethical scale. Psychologists rated sexual boundary violation as more unethical than did physicians (p less than .001). Rationale (p less than .01) and timing (p less than .0001) influenced ratings. Psychologists reported fewer sexualized behaviors than physicians (p less than .05). Professional experience (p less than .01) and sex (p less than .05) were associated with confidence-violating behavior. Overall, 78% of the sample reported attitudes or behaviors associated with boundary violations. The behavior violations were correlated (r = .49). Actual violators rated vignette violators more leniently than did nonviolators (p less than .01).     

早期年龄儿童短时记忆的发展

有关短时记忆的发展问题,如果说在种系发展上已经完成了大量的研究工作,并且做了充分令人信服的、关于在进化中短时记忆不断改善的结论的话,那么,在个体发展上,人的早期短对记忆的发展问题的研究,还是个空白。有关记忆的实验心理学研究,是从儿童生后的第三、四年开始的。以往有关个体发育的早期阶段记忆的发展材料,主要来自《母亲日记》一类的资料,在这类资料中,有关记忆的记述,带有偶然性。在这个时期,记忆的某些形式,其中包括短时记忆,一般地说,还没有研究。     

关于思维活动对识记的作用

我们这篇文章专门用来论讨在直接再现和延缓再现中,记忆和思维相互关系这个当前必须解决的问题А·А·斯米尔诺夫早就证实过,积极的思维活动是提高不随意识记效率的基础。积极思维活动的内容越复杂,就越容易识记。     

把普通教育和职业训练提高到新的水平

学校改革——这是历史发展的必然规律的体现。教育是为了使人适应生活而培养人的,而生活又在不断地发展,它对人的要求也在不断地变化,因此,教育也应当不断地变化。这一改革将根据本世纪末、下世纪初发达的社会主义社会对学校教育的要求来进行。     

The development of the Telic Dominance Scale

The development of a 42-item measure of a number of personality features derived from the theory of psychological reversals is reported. These personality features are (a) the extent to which a person is serious-minded, (b) the extent to which a person plans ahead and organizes himself in the pursuit of goals, and (c) the extent to which a person seeks to avoid arousal. These features together are seen to constitute a personality trait which is described as telic dominance. Data concerning the test-retest reliability, criterion-related and construct validity of the Telic Dominance Scale are presented, together with the scale and scoring key.     

Intrinsic feedback, interpolation, and the closed-loop theory

The amount of experience of a target location, or its surrounding locations, was manipulated to test Adams' (1971) prediction that the perceptual trace (stored perception of the correct response) is based on repeated sensations of the correct response. Sixteen learning trials, each followed by knowledge of results, on a linear-positioning task were permitted for all subjects. Each learning trial required movement to an adjustable physical stop. In learning condition without target experience, movements never terminated in a zone within which the target was interpolated. Other groups experienced movements terminating at the target point. The strength of the perceptual trace was inferred from the ability to move to the target during 20 test trials with the stop removed and without knowledge of the results. Slow movements could be made to a novel location equally as well as to a repeatedly practiced location.     

Lateralized concomitants of human handedness

Literature was reviewed concerning lateral asymmetries of brain and behavior in normal and pathological populations of left-and right-handers. Cerebral asymmetries of structure and function are less pronounced in left-handers as a group than in right-handers as a group, and variability is greater in left-handers.