基于名人面孔视觉特征和语义信息的视觉统计学习

视觉统计学习是指个体依据视觉刺激之间的转接概率来掌握统计规律的过程。本研究通过5个实验探讨了个体基于名人面孔视觉特征和语义信息进行视觉统计学习的加工机制。每个实验均包括熟悉(学习)和测试两个阶段：在熟悉阶段, 让被试观看名人面孔并完成重复图片探测的无关任务; 在测试阶段, 让被试进行二选一迫选任务。其中, 实验1和2分别考察基于名人面孔视觉特征和语义信息的视觉统计学习效果; 实验3分别考察基于名人面孔视觉特征和语义信息视觉进行统计学习的精确性; 实验4进一步考察基于名人面孔视觉特征和语义信息进行视觉统计学习的时间特征; 实验5验证基于名人面孔视觉特征的视觉统计学习具有面孔特异性。结果表明：个体能同时基于名人面孔视觉特征和语义信息进行精确的视觉统计学习; 基于正立名人面孔的视觉统计学习效果显著高于基于倒置名人面孔的视觉统计学习效果; 虽然基于视觉特征和语义信息的统计加工都具有一致的精确性, 但后者需要更多的加工时间。这提示：基于名人面孔视觉特征的视觉统计学习具有面孔特异性, 个体基于名人面孔视觉特征和语义信息的视觉统计学习过程是分离的, 统计运算发生于面孔特征加工完成之后。     

视觉工作记忆巩固机制：固化抑或衰退

视觉工作记忆巩固机制是工作记忆研究领域的前沿科学问题。Vogel等(2006)采用掩蔽的变化检测范式揭示视觉工作记忆巩固过程及其规律, 指出巩固是从容易受到干扰的感觉表征转化为稳定的工作记忆的表征的过程。本文系统梳理了视觉工作记忆巩固的实验范式, 以及相关影响因素的研究成果, 分析了视觉工作记忆巩固现象所反映的内部机制, 指出Vogel等所揭示的视觉工作记忆巩固现象反映的可能并非记忆项目的固化过程, 而是掩蔽刺激对记忆项目的干扰作用的衰退过程。     

掩蔽刺激对目标识别加工的作用：来自fNIRS的证据

信息掩蔽刺激(如随机字母群)对字母视觉搜索的干扰大于能量掩蔽刺激(如将字母群像素随机化后的散点), 但相应的中枢机理还不清楚。本研究采用记录脑代谢激活模式的功能性近红外光学脑成像技术(fNIRS), 考察年轻成年被试分别在字母掩蔽、字母碎片掩蔽、像素掩蔽条件下判断上、下、左、右四个目标字母是否相同时的大脑皮层氧合血红蛋白浓度的变化。结果显示, 依字母、字母碎片、随机散点掩蔽条件顺序, 被试的搜索任务成绩显著递增, 而顶-枕皮层的激活范围与程度显著递减, 表明信息掩蔽较匹配的能量掩蔽对视觉搜索有更大的干扰作用, 并在初级和联合视觉皮层引发更大的激活。在字母碎片掩蔽条件下, 视觉初级皮层部分区域的激活水平与搜索行为绩效的相关显著, 而在字母掩蔽条件下, 视觉联合皮层部分区域的激活水平与搜索行为绩效的相关显著。这进一步说明信息掩蔽中的字母掩蔽和字母碎片掩蔽的掩蔽作用在大脑皮层上所造成的加工负载存在差异。     

对感觉记忆在相同范畴视觉搜索中作用的研究

该文以三种字母卡片为刺激物,通过两种靶字母搜索实验,探讨了感觉记忆在相同范畴视觉搜索中的作用。实验结果显示,感觉记忆和短时记忆信息都可能利用时的搜索成绩,明显高于限用短时记忆信息时的搜索成绩。这表明,感觉记忆信息可以直接用于相同范畴的视觉搜索。     

汉字刺激质量与语义启动间的交互作用

本研究探讨汉字刺激质量与语义启动的相互作用,深入考察汉字识别的内在机制。实验采用真假字判断范式,实验1使用语义相关词对比率较高的实验材料,实验2使用语义相关词对比率较低的实验材料,结果发现：（1）无论语义相关词对比率高还是低,均存在语义启动效应和刺激质量效应,且汉字刺激质量与语义启动之间均存在交互作用;（2）轻度模糊刺激较重度模糊刺激受到的语义启动效应更大。结果表明,即使排除了额外反馈的作用,汉字刺激质量与语义启动之间仍存在交互作用,进一步支持交互激活模型。     

数字-空间联结SNARC效应的编码：视觉空间和言语空间

采用Gevers等的实验范式,以判断数字大小并选择不同言语符号方向信息左右为任务。材料为阿拉伯数字（1、2、8、9）和汉字、英文单词符号（“左”、“右”、“left”、“m#t”）。考察在不同语言符号方向信息下数字-空间联结SANBC效应的编码方式,结果发现：（1）在汉字和英文符号信息下,被试在数字大小比较任务中都表现出SNARC效应;（2）在汉字符号方向信息下。SNARC效应的编码方式主要存在视觉空间和言语空间编码,且以言语空间编码为主;（3）在英文符号方向信息下。SNARC效应的鳊码方式主要是视觉空间编码。     

视觉掩蔽可基于知觉到的客体位置

利用flash—lag效应分离视觉掩蔽中客体的物理位置和知觉位置,以探讨掩蔽效应是否基于知觉到的客体位置。实验中掩蔽刺激做圆周运动,到某一位置时,目标刺激短时呈现,要求被试判断目标刺激（缺角菱形）的缺角方向。通过操作目标呈现时二者之间的相对位置,发现当二者物理位置不重合而知觉位置重合时掩蔽效应最大。该结果表明,视觉掩蔽可基于知觉到的客体位置。     

无关长时记忆表征能否引导视觉注意选择?

与任务相关的长时记忆表征在引导视觉注意选择的过程中扮演着重要的角色,它可以使人们在熟悉的视觉情境中快速搜索目标刺激,并偏离干扰刺激。但当长时记忆表征与任务无关时,还能否引导视觉注意选择?目前还不清楚。实验1采用眼动追踪技术直接比较无关工作记忆表征与无关长时记忆表征在视觉搜索阶段对视觉注意的捕获效应,行为反应时与首次注视点百分率的结果都发现,当无关工作记忆表征在视觉搜索中再次出现时能引导视觉注意偏向到与之匹配的干扰刺激,但无关长时记忆表征并没有表现出类似的注意引导效应;实验2探讨记忆表征由工作记忆系统转移到长时记忆系统的过程中对视觉注意的引导效应,结果发现,随着记忆表征的转移,注意引导效应消失了,实验3排除工作记忆表征的干扰后,依然没有发现无关长时记忆表征对注意的引导效应。以上结果表明,无关长时记忆表征并不能像工作记忆表征一样引导视觉注意选择,工作记忆表征和长时记忆表征对视觉注意的引导属于两个不同的认知过程。     

注意对视听语义整合加工的影响

采用2×3的被试内实验设计,将注意条件和目标刺激类型作为实验变量,考察了指向不同感觉通道的注意对视听语义整合加工的不同影响。结果发现,只有在同时注意视觉和听觉刺激时,被试对语义一致的视听刺激反应最快,即产生冗余信号效应。而在选择性注意一个感觉通道时,语义一致的视听刺激并不具有加工优势。进一步分析发现,在同时注意视觉和听觉时语义一致视听刺激的加工优势源自于其视觉和听觉成分产生了整合。也就是说,只有在同时注意视觉和听觉时,语义一致视听刺激才会产生整合,语义不一致视听刺激不会产生整合。而在选择性注意一个感觉通道时,不论语义是否一致,视听刺激均不会产生整合。     

7~12岁儿童视觉搜索能力的发展

该研究主要考察7~12岁儿童视觉搜索能力的发展。实验结果表明：儿童视觉搜索能力随年龄的增长而提高,性别差异不显著;儿童对三种不同视觉刺激材料（阿拉伯数字、英文字母、汉字）的视觉搜索的反应时没有表现出明显的差异,这个结果与通常的一些实验结果不同。同时,儿童在视觉搜索过程中,判断刺激出现的反应时均明显短于判断刺激没有出现的反应时;两种判断与左右手之间存在着交互作用。     

Single-digit and two-digit Arabic numerals address the same semantic number line.

Many theories about human number representation stress the importance of a central semantic representation that includes the magnitude information of small integer numbers, and that is conceived as an abstract, compressed number line. However, thus far there has been little or no direct evidence that units and teens are represented on the same number line. In two masked priming experiments, we show that single-digit and two-digit Arabic numerals are equally well primed by an Arabic numeral with the same number of digits as by an equally distant Arabic numeral with a different number of digits (e.g. the priming effect of 7 on the target 9 is the same as the priming effect of 11 on the target 9). The finding was obtained both with a number naming task and with a parity judgement task. This is in line with the hypothesis that units and teens are part of a continuous number line.     

Roman digit naming: evidence for a semantic route

Earlier research with monolinguals and bilinguals showed that numbers may be named through both a semantic and a phonological route, depending on the number's language and format (Arabic or verbal), task demands, and naming language. The present study investigated the importance of the semantic route for the processing of a third representation of magnitude, namely Roman digits. Using an interference paradigm, we showed that the processing of Roman target digits is influenced by Arabic digit distractors, both in a naming task and a parity judgment task. Roman digits were processed faster if the target and distractor were of the same magnitude. If this was not the case, processing speed slowed down as the numerical distance between target and distractor increased. This strongly suggests that semantic access is mandatory when naming Roman digits. Implications are discussed for the number processing domain and for models of translation in bilinguals.     

Similarity as an organising principle in short-term memory

Abstract

The role of stimulus similarity as an organising principle in short-term memory was explored in a series of seven experiments. Each experiment involved the presentation of a short sequence of items that were drawn from two distinct physical classes and arranged such that item class changed after every second item. Following presentation, one item was re-presented as a probe for the ‘target’ item that had directly followed it in the sequence. Memory for the sequence was considered organised by class if probability of recall was higher when the probe and target were from the same class than when they were from different classes. Such organisation was found when one class was auditory and the other was visual (spoken vs. written words, and sounds vs. pictures). It was also found when both classes were auditory (words spoken in a male voice vs. words spoken in a female voice) and when both classes were visual (digits shown in one location vs. digits shown in another). It is concluded that short-term memory can be organised on the basis of sensory modality and on the basis of certain features within both the auditory and visual modalities.     

Task-irrelevant distractors in the delay period interfere selectively with visual short-term memory for spatial locations

Visual short-term memory (VSTM) enables the representation of information in a readily accessible state. VSTM is typically conceptualized as a form of “active” storage that is resistant to interference or disruption, yet several recent studies have shown that under some circumstances task-irrelevant distractors may indeed disrupt performance. Here, we investigated how task-irrelevant visual distractors affected VSTM by asking whether distractors induce a general loss of remembered information or selectively interfere with memory representations. In a VSTM task, participants recalled the spatial location of a target visual stimulus after a delay in which distractors were presented on 75% of trials. Notably, the distractor’s eccentricity always matched the eccentricity of the target, while in the critical conditions the distractor’s angular position was shifted either clockwise or counterclockwise relative to the target. We then computed estimates of recall error for both eccentricity and polar angle. A general interference model would predict an effect of distractors on both polar angle and eccentricity errors, while a selective interference model would predict effects of distractors on angle but not on eccentricity errors. Results showed that for stimulus angle there was an increase in the magnitude and variability of recall errors. However, distractors had no effect on estimates of stimulus eccentricity. Our results suggest that distractors selectively interfere with VSTM for spatial locations.     

The extraction of information from visual persistence.

Seven-letter targets were flashed for 50 msec and followed by either a blank adapting field (persisting representation of the stimulus fully available) or a series of continuous cycles of target and mask until the cumulative duration of the target matched the estimated duration of visual persistence (stimulus physically present for same interval as representation). The reportability of information from the targets in the latter case was only 50% that in the former. The interpretation is that visual persistence is an active, continuously operating process rather than a passive neural copy of the stimulus.     

The role of alpha oscillations in deriving and maintaining spatial relations in working memory

Previous research has demonstrated distinct neural correlates for maintenance of abstract, relational versus concrete, sensory information in working memory (WM). Storage of spatial relations in WM results in suppression of posterior sensory regions, which suggests that sensory information is task-irrelevant when relational representations are maintained in WM. However, the neural mechanisms by which abstract representations are derived from sensory information remain unclear. Here, using electroencephalography, we investigated the role of alpha oscillations in deriving spatial relations from a sensory stimulus and maintaining them in WM. Participants encoded two locations into WM, then after an initial maintenance period, a cue indicated whether to convert the spatial information to another sensory representation or to a relational representation. Results revealed that alpha power increased over posterior electrodes when sensory information was converted to a relational representation, but not when the information was converted to another sensory representation. Further, alpha phase synchrony between posterior and frontal regions increased for relational compared to sensory trials during the maintenance period. These results demonstrate that maintaining spatial relations and locations in WM rely on distinct neural oscillatory patterns.     

Linking somatic and symbolic representation in semantic memory: the dynamic multilevel reactivation framework

Biological plausibility is an essential constraint for any viable model of semantic memory. Yet, we have only the most rudimentary understanding of how the human brain conducts abstract symbolic transformations that underlie word and object meaning. Neuroscience has evolved a sophisticated arsenal of techniques for elucidating the architecture of conceptual representation. Nevertheless, theoretical convergence remains elusive. Here we describe several contrastive approaches to the organization of semantic knowledge, and in turn we offer our own perspective on two recurring questions in semantic memory research: (1) to what extent are conceptual representations mediated by sensorimotor knowledge (i.e., to what degree is semantic memory embodied)? (2) How might an embodied semantic system represent abstract concepts such as modularity, symbol, or proposition? To address these questions, we review the merits of sensorimotor (i.e., embodied) and amodal (i.e., disembodied) semantic theories and address the neurobiological constraints underlying each. We conclude that the shortcomings of both perspectives in their extreme forms necessitate a hybrid middle ground. We accordingly propose the Dynamic Multilevel Reactivation Framework—an integrative model predicated upon flexible interplay between sensorimotor and amodal symbolic representations mediated by multiple cortical hubs. We discuss applications of the dynamic multilevel reactivation framework to abstract and concrete concept representation and describe how a multidimensional conceptual topography based on emotion, sensation, and magnitude can successfully frame a semantic space containing meanings for both abstract and concrete words. The consideration of ‘abstract conceptual features’ does not diminish the role of logical and/or executive processing in activating, manipulating and using information stored in conceptual representations. Rather, it proposes that the materials upon which these processes operate necessarily combine pure sensorimotor information and higher-order cognitive dimensions involved in symbolic representation.     

Setting and changing feature priorities in visual short-term memory

Many everyday tasks require prioritizing some visual features over competing ones, both during the selection from the rich sensory input and while maintaining information in visual short-term memory (VSTM). Here, we show that observers can change priorities in VSTM when, initially, they attended to a different feature. Observers reported from memory the orientation of one of two spatially interspersed groups of black and white gratings. Using colored pre-cues (presented before stimulus onset) and retro-cues (presented after stimulus offset) predicting the to-be-reported group, we manipulated observers’ feature priorities independently during stimulus encoding and maintenance, respectively. Valid pre-cues reliably increased observers’ performance (reduced guessing, increased report precision) as compared to neutral ones; invalid pre-cues had the opposite effect. Valid retro-cues also consistently improved performance (by reducing random guesses), even if the unexpected group suddenly became relevant (invalid-valid condition). Thus, feature-based attention can reshape priorities in VSTM protecting information that would otherwise be forgotten.     

语义表征具身理论:情绪在概念表征中的作用

概念如何被表征是认知科学的热点问题,其中抽象概念如何表征是当前具身认知最具争议性的话题之一。与前期概念隐喻理论(强调意象图式)和知觉符号理论(强调情境内省信息)的观点不同,语义表征具身理论强调情绪经验信息在抽象概念表征和加工中的作用。具体而言,具体概念的表征主要来自感觉运动信息,而抽象概念的表征主要来自情绪经验信息和语言信息。研究证明,抽象概念的高情绪经验信息能够促进词汇的加工,且这一促进作用受词汇情绪效价的调节。未来研究应进一步考虑影响情绪经验信息发挥作用的因素,比如语言信息的丰富性、情绪唤醒或个体的情绪状态等。     

Naming digits in a semantic blocking paradigm

It is widely agreed that word numerals are processed similar to other words, and, thus, they can be named without semantic mediation. However, there is no consensus about Arabic digits. Although digits seem to have a preferential link to magnitude representation, there is some evidence indicating a possible asemantic route to access phonological information. In the present study, we used a semantic blocking paradigm to explore this question. In Experiment 1, participants were asked to name digits and pictures or numeral words and name of objects in a semantic blocked context and in a mixed context. For both types of numerical notation we found facilitation in the blocked condition relative to the mixed condition. In Experiment 2, participants named two-digit numbers in a blocked condition (short numerical distance) or in a mixed condition (large numerical distance). Again, facilitation was found for the blocked condition relative to the mixed condition. This pattern of results seems to indicate that Arabic digits, like number words, might be named through an asemantic route.