Sequential and Biomechanical Factors Constrain Timing and Motion in Tapping

The authors examined how timing accuracy in tapping sequences is influenced by sequential effects of preceding finger movements and biomechanical interdependencies among fingers. Skilled pianists tapped sequences at 3 rates; in each sequence, a finger whose motion was more or less independent of other fingers' motion was preceded by a finger to which it was more or less coupled. Less independent fingers and those preceded by a more coupled finger showed large timing errors and change in motion because of the preceding finger's motion. Motion change correlated with shorter intertap intervals and increased with rate. Thus, timing of sequence elements is not independent of the motion trajectories that individuals use to produce them. Neither motion nor its relation to timing is invariant across rates.     

Motor Performance of Stutterers and Nonstutterers on Timing and Force Control Tasks

Recently it has been suggested that speech and manual timing tasks share a common central process (Franz, Zelaznik, & Smith, 1992). Because stuttering is thought to be related to deficits in motoric processes such as timing, stutterers (n = 15) were compared with a set of age-, education-, and sex-matched nonstutterers on timing and isometric force-production tasks. In the timing tasks, subjects flexed and extended the right index finger at the metacarpophalangeal joint at cycle durations of 600, 500, 400, 300, and 200 ms. In the force-production tasks, subjects generated isometric forces to match target force levels displayed on a cathode-ray tube (CRT) screen. There were five levels of force, ranging from .11 to 7.85 newtons. Overall, there were no differences in timing and force-production performance between stutterers and nonstutterers. These results are similar to those obtained recently by Hulstijn, Summers, van Lieshout, and Peters (1992). We suggest that stuttering is not characterized by a general deficit in rhythmic timing. Instead, the motor deficit associated with stuttering should be viewed as speech specific.     

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 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.     

Modality differences in timing and temporal memory throughout the lifespan

The perception of time is heavily influenced by attention and memory, both of which change over the lifespan. In the current study, children (8 yrs), young adults (18–25 yrs), and older adults (60–75 yrs) were tested on a duration bisection procedure using 3 and 6-s auditory and visual signals as anchor durations. During test, participants were exposed to a range of intermediate durations, and the task was to indicate whether test durations were closer to the “short” or “long” anchor. All groups reproduced the classic finding that “sounds are judged longer than lights”. This effect was greater for older adults and children than for young adults, but for different reasons. Replicating previous results, older adults made similar auditory judgments as young adults, but underestimated the duration of visual test stimuli. Children showed the opposite pattern, with similar visual judgments as young adults but overestimation of auditory stimuli. Psychometric functions were analyzed using the Sample Known Exactly-Mixed Memory quantitative model of the Scalar Timing Theory of interval timing. Results indicate that children show an auditory-specific deficit in reference memory for the anchors, rather than a general bias to overestimate time and that aged adults show an exaggerated tendency to judge visual stimuli as “short” due to a reduction in the availability of controlled attention.     

Desire satisfaction,death, and time

Desire satisfaction theories of well-being and deprivationism about the badness of death face similar problems: desire satisfaction theories have trouble locating the time when the satisfaction of a future or past-directed desire benefits a person; deprivationism has trouble locating a time when death is bad for a person. I argue that desire satisfaction theorists and deprivation theorists can address their respective timing problems by accepting fusionism, the view that some events benefit or harm individuals only at fusions of moments in time. Fusionism improves on existing solutions to the timing problem for deprivationism because it locates death’s badness at the same time as both the victim of death and death itself, and it accounts for all of the ways that death is bad for a person. Fusionism improves on existing solutions to the problem of temporally locating the benefit of future and past-directed desires because it respects several attractive principles, including the view that the intrinsic value of a time for someone is determined solely by states of affairs that obtain at that time and the view that intrinsically beneficial events benefit a person when they occur.     

时距加工“长度效应”研究述评

所谓长度效应指随着加工长度的变化, 时距加工机制在认知或神经层面会表现出不一致。近20年来, 关于时距加工是否会出现长度效应存在共同机制假设和差异机制假设两种观点。共同机制假设主张不同长度的时距加工认知或神经机制相同, 且该机制可被标量计时模型解释; 而差异机制假设主张不同长度时距加工的认知或神经机制存在差异, 2~3s、1s、1/2s及1/3s等是区别不同机制的分界位置。文章还指出四个值得思考的问题, 即已获证据的可靠性问题、判定标准的多元化问题、分界位置的确定性问题及理论模型的适用性问题。     

Early Menarche: A Review of Research on Trends in Timing, Racial Differences, Etiology and Psychosocial Consequences

This paper elucidates varying definitions of “early menarche” and reviews evidence in four well-documented areas: (a) A potential trend toward earlier maturation, (b) racial differences in menarcheal timing, (c) etiology of early puberty, and (d) consequences of early puberty. While teachers and physicians perceive menarche as occurring earlier than in the past, mean menarcheal age has remained relatively constant over the past 50 years. Conflicting results concerning racial differences in timing highlight the need for further research to unravel the effects of race and social economic status (SES). Evidence regarding the relative etiological contributions of nutrition, environmental stress, and genetics is evaluated. Maturing earlier than one’s peers has negative consequences for girls, especially when combined with simultaneous stressors. However, the negative psychosocial consequences of early puberty may not last into later adolescence or adulthood. Few studies have investigated early-maturing adolescents’ subjective experience with menarche, particularly those from non-white and non-middle-class backgrounds.This article is based on a paper presented at the 2003 Society for Menstrual Cycle Research Conference in Pittsburgh, PA.     

内隐学习在第二语言语音学习中的作用

本研究以大学生为被试,用符合德语读音规则的人造无意义单词(含4~5个音素)为刺激材料,采用强分离程序———匹配和编辑,并增设时间变量,比较了在先匹配后编辑,先编辑后匹配,只匹配,只编辑4种不同内隐、外显学习方式下被试对语音规则的掌握。结果表明,语音学习中存在内隐学习的优势效应,内隐与外显结合的学习方式最好。此外,实验证实了语音的内隐学习也存在长时效应。     

The effect of reinforcement probability on time discrimination in the midsession reversal task

We examined how biasing time perception affects choice in a midsession reversal task. Given a simultaneous discrimination between stimuli S1 and S2, with choices of S1 reinforced during the first, but not the second half of the trials, and choices of S2 reinforced during the second, but not the first half of the trials, pigeons show anticipation errors (premature choices of S2) and perseveration errors (belated choices of S1). This suggests that choice depends on timing processes, on predicting when the contingency reverses based on session duration. We exposed 7 pigeons to a midsession reversal task and manipulated the reinforcement rate on each half of the session. Compared to equal reinforcement rates on both halves of the session, when the reinforcement rate on the first half was lower than on the second half, performance showed more anticipation and less perseveration errors, and when the reinforcement rate on the first half was higher than on the second half, performance showed a remarkable reduction of both types of errors. These results suggest that choice depends on both time into the session and the outcome of previous trials. They also challenge current models of timing to integrate local effects.     

Vocal responsiveness of preterm infants to maternal infant-directed speaking and singing during skin-to-skin contact (Kangaroo Care) in the NICU

Vocalizations of full-term newborns occur in a short latency time during the neonatal period. Contingent response time of preterm babies is still unknown. An increase of preterm babies’ vocalizations following exposure to parental speech was also observed. Mothers and babies co-modulate their vocalizations in preterm dyads. Purpose: To observe temporal features of maternal and infants’ vocalizations in speaking and singing conditions in preterm dyads. Methods: In a NICU mothers (N = 36) were invited to speak and to sing to their preterm infants during Kangaroo Care. Microanalysis of temporal units were performed with ELAN Software. Results and conclusions: Preterm infants vocalize less often while their mothers speak and sing than during baseline and their vocalizations tend to be more alternating in the speaking condition and more overlapping in the singing condition. It is also concluded that preterm infants take more time to respond to maternal speaking than to maternal singing.