When Can Attention Not Be Divided?

Humans can guide simple concurrent and seemingly independent movements of digits between hands, but it is shown here that they find it impossible to do this with digits within a hand. This inability demonstrates a basic characteristic of the relation between attention and the control of the skeletal musculature: Mechanisms that are available to provide the illusion of concurrent and independent guidance of separate movements between hands are not available within a single-hand control system. There is no reason to believe that the inability to divide focal attention in the guidance of two concurrent controlled activities, as exemplified in the example of within-hand movements, does not also extend to nonmotor processes.     

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.     

Freely Chosen Index Finger Tapping Frequency Is Increased in Repeated Bouts of Tapping

Healthy individuals (n = 40) performed index finger tapping at freely chosen frequency during repeated bouts and before and after near-maximal muscle action consisting of 3 intense flexions of the index finger metacarpal phalangeal joint. One experiment showed, unexpectedly, that a bout of tapping increased the tapping frequency in the subsequent bout. Thus, a cumulating increase of 8.2 ± 5.4% (p < .001) occurred across 4 bouts, which were all separated by 10 min rest periods. Follow-up experiments revealed that tapping frequency was still increased in consecutive bouts when rest periods were extended to 20 min. Besides, near-maximal muscle activation, followed by 5 min rest, did not affect the tapping frequency. In conclusion, freely chosen tapping frequency was increased in repeated bouts of tapping, which were separated by 10–20 min rest periods. The observed phenomenon is suggested to be termed repeated bout rate enhancement.     

Near-term fetal response to maternal spoken voice

Knowledge about prenatal learning has been largely predicated on the observation that newborns appear to recognize the maternal voice. Few studies have examined the process underlying this phenomenon; that is, whether and how the fetus responds to maternal voice in situ. Fetal heart rate and motor activity were recorded at 36 weeks gestation (n = 69) while pregnant women read aloud from a neutral passage. Compared to a baseline period, fetuses responded with a decrease in motor activity in the 10 s following onset of maternal speech and a trend level decelerative heart rate response, consistent with an orienting response. Subsequent analyses revealed that the fetal response was modified by both maternal and fetal factors. Fetuses of women who were previously awake and talking (n = 40) showed an orienting response to onset of maternal reading aloud, while fetuses of mothers who had previously been resting and silent (n = 29) responded with elevated heart rate and increased movement. The magnitude of the fetal response was further dependent on baseline fetal heart rate variability such that largest response was demonstrated by fetuses with low variability of mothers who were previously resting and silent. Results indicate that fetal responsivity is affected by both maternal and fetal state and have implications for understanding fetal learning of the maternal voice under naturalistic conditions.     

Oculomotor involvement in spatial working memory is task-specific

Many everyday tasks, such as remembering where you parked, require the capacity to store and manipulate information about the visual and spatial properties of the world. The ability to represent, remember, and manipulate spatial information is known as visuospatial working memory (VSWM). Despite substantial interest in VSWM the mechanisms responsible for this ability remain debated. One influential idea is that VSWM depends on activity in the eye-movement (oculomotor) system. However, this has proved difficult to test because experimental paradigms that disrupt oculomotor control also interfere with other cognitive systems, such as spatial attention. Here, we present data from a novel paradigm that selectively disrupts activation in the oculomotor system. We show that the inability to make eye-movements is associated with impaired performance on the Corsi Blocks task, but not on Arrow Span, Visual Patterns, Size Estimation or Digit Span tasks. It is argued that the oculomotor system is required to encode and maintain spatial locations indicted by a change in physical salience, but not non-salient spatial locations indicated by the meaning of a symbolic cue. This suggestion offers a way to reconcile the currently conflicting evidence regarding the role of the oculomotor system in spatial working memory.     

大学生恋爱决策中的内隐与外显线索偏好的研究

本研究旨在探索大学生恋爱决策中的内隐和外显线索的偏好差异。研究一在访谈和问卷调查的基础上,筛选出大学生在恋爱决策中关注的十四条线索,并让38名男性和52名女性大学生对这些线索进行重要性评分,从而比较不同性别的被试在线索重要性上的差异,结果显示不同性别的大学生在品行、个人修养、性格、职业、经济条件、家庭背景和学历这些线索上有显著差异;研究二分别选取了男性和女性大学生最为关注的前八条线索,并通过眼动仪探索被试进行恋爱决策时的内隐线索排序,与通过自陈问卷获得的外显线索排序进行比较,旨在探索被试的内隐与外显线索的重要性排序差异。研究二采用恋爱6个月以上关系稳定的眼动被试群体。结果显示,对于不同性别的被试,其内隐与外显条件下在某些线索重要性方面的排序上存在显著差异;女性被试的平均注视时间排序和对线索重要性排序在某些线索上也存在显著差异,而不同性别的被试对某些线索上的平均瞳孔大小排序上也和内隐线索重要性的排序上存在显著差异。     

句法加工中的预测现象及实验证据

句法加工是读者通过整合输入的言语信息来理解句子的过程。句法加工的存在,使得读者能够提前预测文本的信息,提高阅读效率。由于阅读离不开信息整合,研究者提出两类不同的句法理论:句法预测的模块局域性理论和句法预测的互动分析性观点。这两类理论的争论点在于句法加工是单独模块化的自上而下加工,还是自下而上-自上而下的互动分析加工过程。其区别表现为句法预测的作用——前者认为句法预测对句子加工有抑制作用,后者认为句法预测对句子加工起促进作用。来自眼动、ERP等研究的数据佐证了句法预测的存在。未来研究应围绕其差异进行深入探讨,以揭示句法加工的实质。     

自然阅读的脑成像研究及其与眼动技术结合

以往的研究者主要采用单词系列呈现的实验范式对词、句子和篇章等材料进行阅读脑成像研究。针对近年来使用自然阅读范式的功能磁共振(fMRI)研究进行分析,建议在该范式下使用脑-眼动同步记录的方式,并介绍了基于注视编码的fMRI数据分析原理。新的范式和技术提高了fMRI研究的生态效度,有利于对阅读中眼动加工的脑机制进行探索,是相关研究的新趋势。未来需要在自然阅读fMRI实验中结合实验设计及其他技术以克服时间分辨率低的问题,同时要注意探讨阅读和眼动脑区的关系。     

工作记忆负荷、形状干扰对聋人与听力正常人注意捕获影响的眼动研究

通过记录和分析被试的行为和眼动指标,本研究试图探讨不同工作记忆负荷下,形状干扰对聋人与听力正常人不同视野位置上刺激信息捕获注意的异同。研究结果表明：（1）形状干扰刺激虽然没有影响被试视觉加工的认知绩效,但被试的眼动模式会由于工作记忆负荷的改变而改变,高工作记忆负荷时,有形状干扰的注视次数高于无形状干扰。（2）工作记忆负荷、视野位置影响被试视觉加工任务的完成,被试在不同视野位置的加工过程表现出不一致的眼动模式。（3）聋人视觉加工在高工作记忆负荷时存在一定的劣势,但其对不同视野位置的信息加工及形状干扰所产生的注意捕获效应与听力正常人一致。     

Male more than female infants imitate propulsive motion

Few experimental studies investigate the mechanisms by which young children develop sex-typed activity preferences. Gender self-labeling followed by selective imitation of same-sex models currently is considered a primary socialization mechanism. Research with prenatally androgenized girls and non-human primates also suggests an innate male preference for activities that involve propulsive movement. Here we show that before children can label themselves by gender, 6- to 9-month-old male infants are more likely than female infants to imitate propulsive movements. Further, male infants’ increase in propulsive movement was linearly related to proportion of time viewing a male model’s propulsive movements. We propose that male sex-typed behavior develops from socialization mechanisms that build on a male predisposition to imitate propulsive motion.