小学生和成人不同注意条件下的感数与计数加工的比较研究

采用经典的空间线索范式,以成年人和小学二、四、六年级的学生为研究对象,考察了内、外源注意对感数和计数加工过程的影响。结果表明：（1）六年级学生和成人的感数范围为1-3或4,计数范围为4或5以上,二、四年级学生的感数范围在1-3,计数范围在4以上,支持感数和计数分离的观点。（2）对感数加工,成人和六年级学生均不受两种注意条件的影响,而对计数加工,外源性注意条件下的反应比内源性注意快;二年级学生1-6的数量加工受两种注意条件的影响,四年级学生1-5的加工不受两种注意条件的影响。（3）成人和小学生在感数和计数加工上都存在线索效应。以上结果说明：二-四年级是发展的关键期,随着年龄的增加,儿童逐渐有意识地有效利用内源和外源性线索进行数量加工,其注意指向性更明确;从发展的角度为选择注意加工理论提供了发展证据。     

感数的认知机制：从注意到工作记忆

感数(subitizing)是对小数精确而迅速的知觉, 它反映了有机体的一种基本数量表征能力。研究者曾一度认为感数是一个前注意的并行加工过程, 近年来的一些研究发现感数是需要注意资源的, 但是注意资源假设不能有效解释感数与计数的分离。为解决这一困惑, 本文综述了感数和视空间工作记忆的相似性, 在此基础上提出一种新的观点来解释感数的认知机制：视空间工作记忆容量决定了个体一次能精确知觉到的客体的数量, 而注意决定了哪些信息进入视空间工作记忆。     

ERP研究反映感数与计数的不同脑机制

对于较小数目的快速准确认知的“感数”现象一直是一个引人兴趣的问题,这一感数过程到底本质是什么,它与计数过程究竟是同一种加工还是分属两种不同类别,对于这个问题多年来一直存在着争论。本实验的目的在于研究感数加工的本质,运用ERP手段来探索其与计数的不同机制;并且以分心物变量为指标,研究在有分心物呈现时,感数与计数过程将会有哪些变化以及其潜在的神经机制。对14名正常青年人记录感数与计数加工过程中的事件相关脑电位（ERP）。刺激图片由位于屏幕中心的靶(白色矩形)或者靶+分心物(白色圆形)组成,靶的数目分为感数（1－3个靶）及计数（4－6）;而分心物的数目有三种水平：零（无分心物）,与靶的数目相同及两倍于靶的数目。被试计算图片上白色矩形的个数并对所得数目进行奇偶判断,最后根据奇偶性用左右手进行按键反应。行为结果表明,感数与计数的反应时在靶数目之间有显著性差异,靶数目相同时,分心物越多,则被试所需要的反应时就越长。ERP测量表明P1波幅随着靶数目的增加而增大,随着分心物数目的增加而增加;N1波潜伏期随着靶数目的增加和分心物数目增加而减小,N1波幅随着靶数目和分心物的增加而增加;P3波幅随着靶数目的增加而减小,在某些记录点具有靶效应和干扰效应。研究结果提示感数加工具有明显的分心物效应,而计数加工则不然,支持感数与计数分属两种不同功能加工过程的观点,感数加工更易受到分心物出现的干扰。     

有关幼儿数能力研究资料三则

Gelman 根据她与同事的研究,提出婴幼儿计数的五条原则。这五条原则分别是:〈1〉1-1原则(The one-one Principle)这条原则说明,幼儿在计数时是连续地把一个数字,而且是一个不同的数写安排给要计数的每一个项目。首先出现的项目为“1”,其次出现的为“2”,依次类推完成整个计数过程,在使用这条原则时要求,不能跳跃任何一个要计数的项目,也不能对一个项目重复计数,也不能重复使用一个数字,而且在计数完最后一个项目时就应停止。研究发现2岁半到3岁的儿童对该原则可能有一些掌握。     

大学生同一性状态与时间管理:生命时间流逝情绪和流逝注意的中介作用

我国自古便有“通过强调时间流逝而珍惜当下”的教育与文化传统,对这一“时间认知影响时间行为”的作用机理,当前所知不多。采用问卷法对2232名低年级大学生调查,以考察同一性状态、生命时间流逝情绪、流逝注意与时间管理之间的关系.结果显示：（1）同一性获得、延缓状态正向直接预测时间管理倾向各维度（时间价值感、监控观与效能感）;早闭状态直接正向预测时间监控观、负向预测效能感;扩散状态直接负向预测时间价值感和监控观;（2）获得状态通过流逝情绪间接预测监控观和效能感;（3）延缓状态通过流逝情绪、流逝注意间接预测监控观、效能感,还能通过流逝注意间接预测价值感;（4）早闭状态通过流逝注意间接预测时间管理各维度,其中,流逝注意在“早闭—价值”间起完全中介作用。     

5～7岁自闭症谱系障碍幼儿数感的特点

本研究采用《幼儿数感测评量表》对26名自闭症谱系障碍（autism spectrum disorders,ASD）幼儿、20名智力障碍幼儿及32名正常幼儿进行数感能力测评,并比较三组幼儿的数感特点。结果发现：（1）ASD幼儿的数感整体和各维度水平均显著低于正常幼儿,但与智力障碍幼儿相当;（2）三组幼儿数感各维度水平在5～7岁之间无明显变化;（3）三组幼儿在数量比较、数量估算和大小比较的能力水平均领先于其他维度,而类比推理和大小推理均相对落后。另外,ASD幼儿和智力障碍幼儿的体积比较与大小推理、类比推理的能力较为接近,而正常幼儿的体积比较能力显著优于大小推理和类比推理。研究表明5～7岁ASD幼儿的数感能力整体落后于同龄正常幼儿,且数感各维度的能力发展不均衡、不同步。本研究揭示了5～7岁ASD幼儿数感能力发展的特点及需求,可为制定相应数感干预方案、促进其数学学习提供参考。     

PDP再认型实验程序与刺激来源的可鉴别性研究

提出应根据实验程序的不同,把加工分离模型（ＰＤＰ）进一步分为启动型和再认型两类。２个实验考察了刺激来源的可 鉴别性在ＰＤＰ的再认型实验程序中的作用,同时还考察了注意水平、刺激材料和加工水平等因素对词单１刺激项目再认成绩的影 响。结果发现：熟悉感和刺激来源的可鉴别性共同决定了被试在排除测验中的反应;汉字作刺激材料并不影响实验结果。     

知道感（FOK）和不知道感（FOnK）的实验分离

新近的脑成像研究结果提示：“知道感”（FOK）与“不知道感”（FOnK）可能是由两种不同的认知与脑机制所实现的。尽管这一设想质疑了以往的知道感研究中对此二者不加区分的处理方法,但脑成像研究在本质上是一种相关研究,因而并不能提供因果性的推论。这项行为实验将加工深度对FOK和FOnK的影响分开来加以考察,结果发现：深度加工只能使FOK的预测准确性增加,但却不但不能使FOnK的预测准确性增加,反而会使之降低。上述结果在（1）被试内设计,（2）被试间设计,（3）排除熟悉性所导致的不确定的再认等三种情况下都成立。上述结果为知道感的“双过程假设”提供了来自行为研究的证据。     

即时通讯工具使用体验及其与使用动机和偏好的关系模型

以大学生即时通讯工具（IM）用户为被试,采用因素分析技术探讨了IM使用体验的结构,并建构了IM使用动机与使用偏好和使用体验的关系模型。结果发现：（1）IM使用体验主要包括功能性体验和情感性体验两个基本维度。其中,前者主要涉及控制感、易用感和卷入感等三个因素,而后者则主要涉及乐趣感、愉悦感和互惠感等三个因素;（2）基于上述模型形成的“IM使用体验问卷”具有较理想的项目区分度、内部一致性信度、构想效度和区分效度;（3）基于人际沟通动机的IM用户更关注IM的易用性、可控制性和卷入程度等功能特性,而基于信息获取动机和休闲娱乐动机的IM用户更关注IM的愉悦性、乐趣性和互惠性等情感特性。     

一种新的归因模型──“异常条件聚焦模型”评价

一种新的归因模型──“异常条件聚焦模型”评价刘永芳,刘金平（华东师范大学心理学系）（河南大学教育系）０引言近年来,以Ｋｅｌｌｅｙ提出的“方差分析模型”（ＡＮＯＶＡ）为代表的传统归因理论受到了来自各方面的怀疑和批评。研究者们注意的焦点逐渐转向了人们实际...     

Subitizing and counting in typical and atypical development

Enumeration performance in standard dot counting paradigms was investigated for different age groups with typical and atypically poor development of arithmetic skills. Experiment 1 showed a high correspondence between response times and saccadic frequencies for four age groups with typical development. Age differences were more marked for the counting than the subitizing range. In Experiment 2 we found a discontinuity between subitizing and counting for dyscalculic children; however, their subitizing slopes were steeper than those of typically developing control groups, indicating a dysfunctional subitizing mechanism. Across both experiments a number of factors could be identified that affect enumeration in the subitizing and the counting range differentially. These differential patterns further support the assumption of two qualitatively different enumeration processes.     

The role of pattern recognition in children's exact enumeration of small numbers

Enumeration can be accomplished by subitizing, counting, estimation, and combinations of these processes. We investigated whether the dissociation between subitizing and counting can be observed in 4‐ to 6‐year‐olds and studied whether the maximum number of elements that can be subitized changes with age. To detect a dissociation between subitizing and counting, it is tested whether task manipulations have different effects in the subitizing than in the counting range. Task manipulations concerned duration of presentation of elements (limited, unlimited) and configuration of elements (random, line, dice). In Study 1, forty‐nine 4‐ and 5‐year‐olds were tested with a computerized enumeration task. Study 2 concerned data from 4‐, 5‐, and 6‐year‐olds, collected with Math Garden, a computer‐adaptive application to practice math. Both task manipulations affected performance in the counting, but not the subitizing range, supporting the conclusion that children use two distinct enumeration processes in the two ranges. In all age groups, the maximum number of elements that could be subitized was three. The strong effect of configuration of elements suggests that subitizing might be based on a general ability of pattern recognition.     

Do the magnocellular and parvocellular visual pathways contribute differentially to subitizing and counting?

We investigated the neurobiologies! basis of visual processes involved in object enumeration. Subitizing, the ability to rapidly and accurately enumerate four or fewer objects, is thought to depend on preattentive processing of visual stimuli, whereas counting of more numerous objects is thought to require serial shifts of attention. We attempted to distinguish between the hypothesis that the magnocellular (M) visual pathway is the preferential route for subitizing, and the alternative hypothesis that there is no selectivity for the M pathway or its counterpart, the parvocellular (P) visual pathway, in visual object enumeration. Green rectangles were presented on an equiluminant red background to impair M pathway processing. This slowed enumeration performance relative to a control condition in which object/background luminance differed, especially when the rectangles were relatively large and widely spaced and had constant retinal eccentricity. When low luminance contrast was used to impair processing along the P pathway, enumeration performance was slowed relative to a high-contrast control condition, especially when the rectangles were small and closely spaced. Overall, our manipulations affected enumeration performance without selectivity for subitizing or counting ranges and without altering the slope of the functions relating reaction time to numerosity. Thus, our results favor the hypothesis that visual enumeration does not depend preferentially on either the M or the P pathway.     

Effects of distraction on visual enumeration in children and adults

Speeded enumeration of visual stimuli typically produces a bilinear function, with a shallow subitizing rate (<100 ms/item) up to 3-4 items (subitizing span) and a steeper counting rate (~300 ms/item) thereafter. FINST theory (L. M. Trick & Z. W. Pylyshyn, 1993, 1994) suggests that subitizing of targets is possible in the presence of distractors if attention is not required for target detection, but this has not been tested in children. The present study explored enumeration without distractors (Os alone) and with distractors (Os among Xs) in 35 children aged 6-11 years and 17 adults. Subitizing span increased significantly from childhood to adulthood, and counting rate increased significantly with age. Bilinear functions were significantly better than linear fits to the data for most children and adults both without distractors (97% and 100%, respectively) and with distractors (89% and 94%), consistent with their efficient visual search for a single O among multiple Xs. These findings are discussed in comparison with those from new modeling of earlier enumeration data from young and older adults, revealing striking asymmetries in subitizing with distractors between development and aging.     

Intentional subitizing: exploring the role of automaticity in enumeration

Subitizing is traditionally described as the rapid, preattentive and automatic enumeration of up to four items. Counting, by contrast, describes the enumeration of larger sets of items and requires slower serial shifts of attention. Although recent research has called into question the preattentive nature of subitizing, whether or not numerosities in the subitizing range can be automatically accessed is yet to be empirically tested. In the current study, participants searched for two pre-defined digits in a circular visual-search array. Distractor dots of various set sizes were placed at the centre of the array. Despite the relevance of the distractor numerosities to the target detection task, the distractors did not influence target detection, thereby suggesting that their numerosities were not automatically accessed in Experiment 1. In Experiment 2, participants were explicitly instructed to enumerate the distractor dots. Here, congruent and incongruent distractor numerosities influenced the target detection task, thereby revealing that the distractor dots were capable of generating interference. Experiment 3 ensured that dots were attended by asking participants to detect the luminance of dots. Data confirmed that subitizing was not automatic. The present study also supported the alleged discontinuity between the subitizing and counting ranges because an examination of reaction time gradients in Experiment 2 found the counting gradient to be significantly steeper than the subitizing gradient. In sum, the results suggest that subitizing is a distinct but non-automatic style of enumeration.     

More than superstition: differential effects of featural heterogeneity and change on subitizing and counting

This study investigates the effects of item heterogeneity (differences in color and shape) and moment-to-moment feature change as it relates to the issue of whether subitizing and counting involve different processes. Participants enumerated displays of up to eight items that were either homogeneous or heterogeneous. In situations where the heterogeneous displays always had approximately half of the items of one type and half of the other, heterogeneity significantly sped enumeration in the counting range (6-8 items) and significantly slowed enumeration in the subitizing range (1-3 items), a dissociation that suggests that subitizing and counting involve different operations. Moment-to-moment feature change had no effect on subitizing. However, feature change slowed counting, but only when participants were enumerating heterogeneous items that were half of one type and half of the other, as might be expected if participants were using differences in features to select items by type.     

Is subitizing a unique numerical ability?

Two models that predict the relation between mean enumeration time and numerosity in a speeded enumeration experiment are tested. The first is a bilinear two-process model, and the second is a log-linear single-process model. Previously, support for the bilinear model has provided evidence for the existence of a unique numerical ability called “subitizing.” Both models are shown to yield close approximations to the empirical data, but at the same time to consistently violate the robust shape of these data. Two fundamental discrepancies exist: (1) Enumeration of singleelement displays is unpredictably fast, both in the data reported here and elsewhere, and (2) the response-time function for multiple elements is continuously convex upward, with a significant log-quadratic component. The findings support the contention that enumeration is a capacitylimited process, but no statistically reliable change in processing character, that is, from subitizing to some other process, is evident in enumeration of displays of up to six elements.     

What dot clusters and bar graphs reveal: subitizing is fast counting and subtraction

In two studies, we found that dot enumeration tasks resulted in shallow-sloped response time (RT) functions for displays of 1-4 dots and steep-sloped functions for displays of 5-8 dots, replicating results implicating subitizing and counting processes for low and high ranges of dots, respectively. Extracting number from a specific type of bar graph within the same numerical range produced a shallow-sloped but scallop-shaped RT function. Factor analysis confirmed two independent subranges for dots, but all bar graph values defined a unitary factor. Significantly, factor scores and asymmetries both showed correlations of bar graph recognition to dot subitizing but not to dot counting, strongly suggesting that subitizing was used in both enumeration of low numbers of dots and bar graph recognition. According to these results, subitizing appears to be a nonverbal process operating flexibly in either additive or subtractive fashion on analog quantities having spatial extent, a conclusion consistent with a fast-counting model of subitizing but not with other models of the subitizing process.     

The role of attention in subitizing

The process of rapidly and accurately enumerating small numbers of items without counting, i.e. subitizing, is often believed to rest on parallel preattentive processes. However, the possibility that enumeration of small numbers of items would also require attentional processes has remained an open question. The present study is the first that directly contrasts the preattentive and attentive models of subitizing. We used an inattentional blindness paradigm to manipulate the availability of attentional resources during enumeration. In the inattention condition, the items to be enumerated were presented unexpectedly while participants focused on a line length comparison task. Divided- and full-attention conditions were also included. The results showed that only numbers one and two could be enumerated when the effects of attention were minimized. Freeing attentional resources increased the enumeration accuracies considerably, including for number two. The results suggest that even for enumerating small numbers, the attentional demands increase as the number of objects increases.