"Proper" Binormal ROC Curves: Theory and Maximum-Likelihood Estimation

The conventional binormal model, which assumes that a pair of latent normal decision-variable distributions underlies ROC data, has been used successfully for many years to fit smooth ROC curves. However, if the conventional binormal model is used for small data sets or ordinal-category data with poorly allocated category boundaries, a "hook" in the fitted ROC may be evident near the upper-right or lower-left corner of the unit square. To overcome this curve-fitting artifact, we developed a "proper" binormal model and a new algorithm for maximum-likelihood (ML) estimation of the corresponding ROC curves. Extensive simulation studies have shown the algorithm to be highly reliable. ML estimates of the proper and conventional binormal ROC curves are virtually identical when the conventional binormal ROC shows no "hook," but the proper binormal curves have monotonic slope for all data sets, including those for which the conventional model produces degenerate fits. Copyright 1999 Academic Press.     

Attentional distribution in the visual field duringsame-different judgments as assessed by response competition

Judgments ofsame anddifferent on a comparison task have been found to be subject to response competition if an irrelevant stimulus is presented in the display along with the target stimuli. For example, the reaction time for judging two letters the same is markedly increased if a different but irrelevant letter is also present in the display (C. W. Eriksen, O’Hara, & B. [A.] Eriksen, 1982). We have made use of this competition effect to map the visual attentional field in two dimensions. In two experiments, we varied the size of the attended area by varying the separation of the comparison stimuli. The boundaries of the attended area were mapped by varying the location of a response-competitive irrelevant noise letter. On this task, the attended area was found to be elliptical in shape, with the location of the target stimuli defining the major axis. The minor axis of the ellipse increased in direct proportion to increases in the major axis. Rather than interpret these field effects in terms of areas of enhanced processing, we propose that instead they represent the limits or failures in inhibition of competing stimulation.     

图式与句式教学:一个转折复句的教学实验

本研究根据图式理论设计转折复句的教学实验。实验对象是54个小学五年级的学生。研究发现：实验组无论在转折复句的辨认、改正和写作的表现．都明显地优于控制组。其中以改正能力的差异最明显,而且辨认、改正和写作能力的相关系数也很高。     

越描越黑

就在前不久的2005年2月26日,中央电视台新闻联播播放了一条新闻,表扬华中科技大学“建设网络教育新型平台,拓展思想政治教育领域”。报道中,华中科大党委副书记刘献君说:“过去我们的人文讲座,是在教室里面。现在大学生自己把它搬到网上直播……扩大了覆盖面,提高了教育效果。”点评:所谓“过去我们的人文讲座”,不知是否包括那个     

Visual working memory enhances target discrimination accuracy with single-item displays

The maintenance of information in visual working memory has been shown to bias the concurrent processing in favor of matching visual input. The present study aimed to examine whether this bias can act at an early stage of processing to enhance target feature perception in single-item displays. Participants were sequentially presented with two distinct colored stimuli as memory samples and a retro-cue indicating which of the two samples should be maintained for subsequent memory test. During the retention interval, they had to discriminate the gap orientation of a Landolt target presented through a single visual stimulus that could match one or neither of the two samples. Across two experiments, we consistently found that discrimination performance was more accurate when the Landolt target was situated within a stimulus that matched the sample being retained in visual working memory, as compared with when the target was not. This effect cannot be attributed to the mechanism of passive priming, because we failed to observe priming effects when the stimulus containing the target matched the sample that was retro-cued to be irrelevant to the working memory task, as compared to when the stimulus matched neither sample. Given the fact that target stimuli were presented in single-item displays wherein external noise was precluded, the present findings demonstrate that the working memory bias of visual attention operating in the absence of stimulus competition facilitates early perceptual processing at the attended location via signal enhancement.

     

Divergent thinking and constructing episodic simulations

Divergent thinking likely plays an important role in simulating autobiographical events. We investigated whether divergent thinking is differentially associated with the ability to construct detailed imagined future and imagined past events as opposed to recalling past events. We also examined whether age differences in divergent thinking might underlie the reduced episodic detail generated by older adults. The richness of episodic detail comprising autobiographical events in young and older adults was assessed using the Autobiographical Interview. Divergent thinking abilities were measured using the Alternative Uses Task. Divergent thinking was significantly associated with the amount of episodic detail for imagined future events. Moreover, while age was significantly associated with imagined episodic detail, this effect was strongly related to age-related changes in episodic retrieval rather than divergent thinking.     

关于民初中国灵学问题研究的综述与展望

长期以来,学术界对民初中国灵学问题的研究主要围绕中国近代史和伪科学角度展开,在着眼于批判的基础上逐渐勾勒出其大体轮廓,为下一步研究提供了借鉴。同时,这些研究在资料发掘与史实描述、分析视角与问题意识等方面,仍有补充和转换的空间。     

学优儿童学习适应性、学习习惯和应试技能及其关系

采用《儿童学习适应性调查表（I）、（II）》和《学习习惯与应试技能自我测查表》对231名学优儿童的学习适应性及其相关因素进行调查。结果表明：（1）学优儿童和学习不良儿童的学习适应性、学习习惯和应试技能存在显著性差异;（2）城市学优儿童的学习生活、学习习惯、学习方法、阅读习惯和技能明显优于农村学优儿童;（3）学优女生在学习适应性明显好于男生,但女生有独立性差、情绪障碍等症状,而学优男生则在学习习惯方面不如女生。在学习习惯与应试技能方面则不存在显著的性别差异;（4）除了对学校的态度因子外,学优儿童学习适应性与其学习习惯和学习方法、阅读习惯和技能、准备与应试等有显著性相关。     

刺激呈现时间对汉字语义加工脑偏侧化的影响

以往关于汉字字词识别脑功能偏侧化的研究发现了左半球优势、右半球优势或者大脑两半球均势三种不同的结果。该研究采用一侧化Stroop范式(刺激分别只呈现于左视野、中央视野或右视野中),通过系统地改变刺激呈现时间以期探讨刺激呈现时间是可以解释这些不一致结果的可能因素之一。结果显示:对于右利手被试,在刺激呈现时间为60 ms时右半球出现了较强的Stroop效应,在刺激呈现200 ms时左右半球的Stroop效应没有表现出差异,在刺激呈现时间较长时左半球表现出较强的Stroop效应。该结果提示,随着刺激呈现时间的延长,语义优势发生了从右半球到左半球的转换。