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.     

Processing time predictions of current models of perception in the classic additive factors paradigm

This article explores the consequences for factorial additivity in a Sternberg [(1969). The discovery of processing stages: Extensions of donders method In: W.G. Koster (Ed.), Attention and performance II, Acta Psychologica, 30, 276-315] additive-factors paradigm of the assumptions adopted by models of perception that relate the representation of a stimulus to decision time. Three example models, signal detection theory with the latency-distance hypothesis, stochastic general recognition theory, and a random walk model of exemplar classification, are interrogated to determine what type of interaction they predict factors will yield in a hypothetical factorial (choice) reaction time experiment in which the ‘empirical’ factors’ effects are manifest as parameter changes. All frameworks make the critical assumption that decision time depends on the perceptual representation of the stimulus as well as the architecture. As a consequence, nonadditivity of factors thought to affect different “stages” in the classical approach emerges within the current modeling approach. The nature of this influence is revealed through analytic investigations and simulation. Earlier empirical findings of failures of selective influence that have defied adequate explanation are reinterpreted in light of the present findings.     

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.     

Early top-down influences on bistable perception revealed by event-related potentials

A longstanding debate exists in the literature concerning bottom-up vs. top-down influences on bistable perception. Recently, a technique has been developed to measure early changes in brain activity (via ERPs) related to perceptual reversals (Kornmeier & Bach, 2004). An ERP component, the reversal negativity (RN) has been identified, and is characterized as an increase in negative potential over the posterior scalp from 150 to 350 ms for perceptual reversals compared to perceptual stability. This finding, although interesting, has not helped resolve issues related to the bottom-up vs. top-down debate because top-down influences have not been directly manipulated. The current study focused on resolving some of these issues by measuring the RN while observers maintained one of three 'intentional approaches', (1) try to reverse perception as often as possible, (2) try to stabilize perception for as long as possible, and (3) maintain a passive approach. Enhancements in RN amplitude were found for the intention-to-reverse condition compared to the passive condition. This finding suggests an early influence (150 ms) of top-down control on perceptual reversals of bistable figures. Results are discussed in terms of competing attention shifting vs. fatigue-based theories of bistable perception.     

不同类型的知觉刺激对语言理解的影响

采用知觉负载范式探讨知觉刺激对语言理解的影响。实验1考察被试在加工听觉概念和视觉概念时的表征形式。实验2进一步探讨在同一通道内部,形状概念和视觉概念的表征形式。实验1发现,在进行语言理解时,如果存在听知觉负荷,加工语言中的听觉信息时会变慢。如果存在视知觉负荷,加工语言中的视觉信息时错误率会增加。实验2发现,在涉及视觉信息的语言理解中,颜色知觉负荷产生了广泛的影响,而形状知觉负荷没有表现出这种效应。总的实验结果表明,不同类型的知觉刺激对语言理解产生了不同的影响。语言理解中存在着模态化和非模态化两种不同的加工模式。     

宫内生长受限分娩时间决策

宫内生长受限（IUGR）是导致围产儿死亡的常见原因之一。分娩时间是IUGR临床决策的关键问题,IUGR分娩时间的临床决策需对其病因、病理生理、健康效益、医疗代价、产前检测等进行辩证综合分析,采用循证医学的方法,科学决策,个体化决策,力求减少不良后果发生。     

Perceptual adaptation to non-native speech

This study investigated talker-dependent and talker-independent perceptual adaptation to foreign-accent English. Experiment 1 investigated talker-dependent adaptation by comparing native English listeners' recognition accuracy for Chinese-accented English across single and multiple talker presentation conditions. Results showed that the native listeners adapted to the foreign-accented speech over the course of the single talker presentation condition with some variation in the rate and extent of this adaptation depending on the baseline sentence intelligibility of the foreign-accented talker. Experiment 2 investigated talker-independent perceptual adaptation to Chinese-accented English by exposing native English listeners to Chinese-accented English and then testing their perception of English produced by a novel Chinese-accented talker. Results showed that, if exposed to multiple talkers of Chinese-accented English during training, native English listeners could achieve talker-independent adaptation to Chinese-accented English. Taken together, these findings provide evidence for highly flexible speech perception processes that can adapt to speech that deviates substantially from the pronunciation norms in the native talker community along multiple acoustic-phonetic dimensions.     

Accommodating variation: dialects, idiolects, and speech processing

Listeners are faced with enormous variation in pronunciation, yet they rarely have difficulty understanding speech. Although much research has been devoted to figuring out how listeners deal with variability, virtually none (outside of sociolinguistics) has focused on the source of the variation itself. The current experiments explore whether different kinds of variation lead to different cognitive and behavioral adjustments. Specifically, we compare adjustments to the same acoustic consequence when it is due to context-independent variation (resulting from articulatory properties unique to a speaker) versus context-conditioned variation (resulting from common articulatory properties of speakers who share a dialect). The contrasting results for these two cases show that the source of a particular acoustic-phonetic variation affects how that variation is handled by the perceptual system. We also show that changes in perceptual representations do not necessarily lead to changes in production.